Nonvolatile magnetic memory device and method of writing data into tunnel magnetoresistance device in nonvolatile magnetic memory device

A nonvolatile magnetic memory device having a nonvolatile magnetic memory array comprising write-in word line(s), bit lines and tunnel magnetoresistance devices, wherein when data is written into the tunnel magnetoresistance device, a current I(m)RWL is passed through the m-th-place write-in word line, a current g(0)·I(n)BL is passed through the n-th-place bit line, and at the same time, a current g(k)·I(n)BL is passed through the q-th-place bit line (q=n+k, k is ±1, ±2, . . . , and the total number of the lines is K), and a spatial FIR filter assuming magnetic fields, which are supposed to be formed in the n-th-place bit line and the bit lines that are K in number by the current I(n)BL, to be discrete pulse response and assuming the coefficients g(0) and g(k) to be tap-gains is constituted of the n-th-place bit line and the bit lines that are K in number.

BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT

The present invention relates to a nonvolatile magnetic memory device and a method of writing data into a tunnel magnetoresistance device in a nonvolatile magnetic memory device. More specifically, the present invention relates to a nonvolatile magnetic memory device called a TMR (Tunnel Magneto resistance) type MRAM (Magnetic Random Access Memory) and a method of writing data into a tunnel magnetoresistance device in such a nonvolatile magnetic memory device.

With great diffusion of information communication machines, particularly, personal small machines such as personal digital assistances, various semiconductor devices such as a memory, a logic and so on, constituting such machines are being demanded to cope with higher performances such as a higher degree of integration, faster operation capability and lower power consumption. Particularly, a nonvolatile memory is considered indispensable in the ubiquitous era. Even if the depletion of a power supply or some troubles occur or a server is disconnected to a network due to some failure, important information can be stored or protected with a nonvolatile memory. Further, recently available personal digital assistances are designed such that the power consumption is reduced to a lowest level possible by maintaining non-operating circuit blocks in a standby state, and the waste of power consumption and a memory can be avoided if a nonvolatile memory capable of working as a fast-speed work memory and a mass-storage memory can be realized. Further, if a fast-speed and mass-storage nonvolatile memory can be realized, the “instant-on” function of booting in the instance of turning on power can be made possible.

The nonvolatile memory includes a flash memory using a semiconductor material and a ferroelectric nonvolatile semiconductor memory (FERAM, Ferroelectric Random Access Memory) using a ferroelectric material. However, the flash memory has a defect that the writing speed is slow since it is in the order of microseconds. On the other hand, in FERAM, the number of times of re-writability thereof is 1012to 1014, and the number cannot be said to be sufficient for replacing SRAM or DRAM with FERAM, and there is pointed out another problem that the micro-fabrication of a ferroelectric layer is difficult.

As a nonvolatile memory free of the above defects, a nonvolatile magnetic memory device called MRAM (Magnetic Random Access Memory) is in the limelight. The MRAM at an early development stage was based on a spin valve using a GMR (Giant MagnetoResistance) effect. Since, however, the memory cell resistance against a load is as low as 10 to 100 ohms, the power consumption per bit on readout is large, and the defect is that it is difficult to attain the capacity of mass storage.

While the MRAM using a TMR (Tunnel MagnetoResistance) effect only had a resistance change ratio of 1–2% at room temperature at an early development stage, it has come to be possible to obtain a resistance change ratio close to 20% in recent years, so that the MRAM using the TMR effect is highlighted. The TMR-type MRAM has a simple structure and enables easy scaling, and recording is made by the rotation of a magnetic moment, so that the number of times of possible re-writing is great. Further, it is expected that the TMR-type MRAM is very rapid with regard to an access time period, and it is already said that the TMR-type MRAM is capable of an operation at 100 MHz.

FIG. 5shows a schematic partial cross-sectional view of a TMR-type MRAM (to be simply referred to as “MRAM” hereinafter). The MRAM comprises a transistor for selection TR constituted of a MOS-type FET and a tunnel magnetoresistance device TMJ.

The tunnel magnetoresistance device TMJ has a stacking structure constituted of a first ferromagnetic layer31, a tunnel barrier34and a second ferromagnetic layer35. More specifically, the first ferromagnetic layer31has a two-layer structure, for example, of an anti-ferromagnetic layer32positioned below and a ferromagnetic layer (called a reference layer or a pinned magnetic layer33as well) positioned above and has an intense unidirectional magnetic anisotropy due to an exchange interaction working between these two layers. The second ferromagnetic layer35of which the magnetization direction rotates relatively easily is also called a free layer or memory layer. The second ferromagnetic layer will be called a memory layer35hereinafter. The tunnel barrier34works to cut a magnetic coupling between the memory layer35and the pinned magnetic layer33, and a tunnel current flows in the tunnel barrier34. A bit line BL for connecting the MRAMs is formed on a third insulating interlayer26. A top coating film36formed between the bit line BL and the memory layer35works to prevent mutual diffusion of atoms constituting the bit line BL and atoms constituting the memory layer35, to reduce a contact resistance and to prevent the oxidation of the memory layer35. In Figure, reference numeral37indicates a lead-out electrode connected to the lower surface of the anti-ferromagnetic layer32.

Further, a write-in word line RWL is arranged below the tunnel magnetoresistance device TMJ through a second insulating interlayer24. Generally, the extending direction (first direction) of the write-in word line RWL and the extending direction (second direction) of the bit line BL cross each other at right angles.

The transistor for selection TR is formed in that portion of a semiconductor substrate10which portion is surrounded by a device isolation region11, and the transistor for selection TR is covered with a first insulating interlayer21. One source/drain region14B is connected to the lead-out electrode37of the tunnel magnetoresistance device TMJ through a connecting hole22constituted of a tungsten plug, a landing pad23and a connecting hole25constituted of a tungsten plug. The other source/drain region14A is connected to a sense line16through a tungsten plug15. InFIG. 5, reference numeral12indicates a gate electrode, and reference numeral13indicates a gate insulating film.

In an MRAM array, the MRAM is arranged in an intersecting point (overlap region) of the bit line BL and the write-in word line RWL.

When data is written into the above-constituted MRAM, a current IBLis passed through the bit line BL and a current IRWLis passed through the write-in word line RWL, to form a synthetic magnetic field, and the direction of magnetization of the second ferromagnetic layer (memory layer35) is changed by means of the synthetic magnetic field, whereby “1” or “0” is recorded into the second ferromagnetic layer (memory layer35).

Data is read out by bringing the transistor for selection TR into an ON-state, passing a current through the bit line BL and detecting a tunnel current change caused by a magnetoresistance effect with the sense line16. When the magnetization direction of the memory layer35and the counterpart of the pinned magnetic layer33are the same, a low-resistance state results (this state represents, for example, “0”), and when the magnetization direction of the memory layer35and the counterpart of the pinned magnetic layer33are antiparallel, a high-resistance state results (this state represents, for example, “1”).

FIG. 38shows an asteroid curve of the MRAM. A current is passed through the bit line BL and a current is passed through the write-in word line RWL, and as a result, a synthetic magnetic field is generated. Data is written into the tunnel magnetoresistance device TMJ constituting the MRAM on the basis of the synthetic magnetic field. A magnetic field (HEA) in the easy-magnetization axis direction of the memory layer35is formed due to a writing-in current flowing in the bit line BL, and a magnetic field (HHA) in the difficult-magnetization axis direction of the memory layer35is formed due to a current flowing in the write-in word line RWL. In some MRAM constitution, a magnetic field (HHA) in the difficult-magnetization axis direction of the memory layer35is formed due to a writing-in current flowing in the bit line BL, and a magnetic field (HEA) in the easy-magnetization axis direction of the memory layer35is formed due to a current flowing in the write-in word line RWL.

The asteroid curve shows an inversion threshold value of magnetization direction of the memory layer35due to the synthetic magnetic field (synthesis of magnetic field vectors of the magnetic field HA and the magnetic field HEAto be exerted on the memory layer35). When a synthetic magnetic field corresponding to an outside (OUT1, OUT2) of the asteroid curve is generated, the magnetization direction of the memory layer35is inverted, so that data writing is performed. When a synthetic magnetic field corresponding to an inside (IN) of the asteroid curve is generated, the inversion of magnetization of the memory layer35does not take place. Further, onto the MRAM other than the MRAM which is positioned in the overlap region of the write-in word line RWL and the bit line BL in which the currents are flowing, a magnetic field is additionally exerted by the write-in word line RWL or bit line BL alone, and when such a magnetic field is greater than a unidirectional inversion magnetic field HK[in a region (OUT2) outside dotted lines inFIG. 38], the magnetization direction of the memory layer35constituting the MRAM other than the MRAM which is positioned in the overlap region is also inverted. Therefore, only when the synthetic magnetic field is outside the asteroid curve and is in a region (OUT1) inside the dotted lines inFIG. 38, selective writing into the selected MRAM is possible.

As described above, TMR-type MRAM has an advantage that a higher speed and a higher degree of integration are easily attained. Actually, however, a magnetic field generated during writing data into a certain MRAM may destroy data stored in MRAM adjacent to the above MRAM.

As shown inFIG. 39, there is assumed a state where three conductor lines (L1, L0, L2) have an infinite length, these conductor lines are placed apart side by side at a distance of d, a current of I0(ampere) flows in the conductor line L0and a current of −I0(ampere) flows in each of the conductor lines L1and L2. If distances from an arbitrary point P (X,Y) to the conductor lines L0, L1, L2are r0, r1and r2, the magnetic fields HXand HYin the directions of X axis and Y axis can be determined on the basis of the following expressions (3-1) and (3-2). Angles at which the straight lines connecting the arbitrary point (X,Y) and the conductor lines L0, L1, L2form with the X axis are θ0, θ1and θ2. InFIG. 39, further, the magnetic field generated by the conductor line L0is represented by an arrow H0, the magnetic field generated by the conductor line L1is represented by H1, and the magnetic field generated by the conductor line L2is represented by an arrow H2.

As shown inFIG. 5, a distance from the center of the bit line BL in the thickness direction to the center of the second ferromagnetic layer (memory layer)35is assumed to be “h”, and a distance from the center of the bit line in the width direction to the center of an adjacent bit line in the width direction is assumed to be “d”. And, it is assumed that β=(h/d).

The conductor lines L0, L1, L2are assumed to be three bit lines arranged in parallel in the X axis direction, the conductor line L0is assumed to pass the origin (0,0) of the Gauss' coordinate, and it is assumed that I1=0 (ampere). In this case, the value of H(x,h)at a point represented by a coordinate (X,h) is calculated according to the following expression (4).

In the above expression, I0is normalized such that when X=0, H(x,h)=1. In this case, the value of I0is as follows.
I0=2n·h(5)

The expression (5) is substituted in the expression (4) to give the following expression (6). A normalized magnetic field H(X,h)is represented by HN(X,h).
HN(X,h)=h2/(X2+h2)  (6)

When d·x is denoted by X, the expression (6) is substituted in the expression (7), using β=(h/d).

FIG. 40shows HN(x,h)that are calculation results from the expression (7) when the value of β=(h/d) is 0.1, 0.5 and 1.0.

When the value of β=(h/d) is 0.1, that is, when the distance “d” from the center of the bit line in the width direction to the center of the adjacent bit line in the width direction is 10 times the distance “h” to the center of the second ferromagnetic layer35in the thickness direction, HN(x,h)in the case of x=±1.0, that is, in the second ferromagnetic layer35of the adjacent tunnel magnetoresistance device TMJ, is nearly 0, and there is no interference of the magnetic fields between adjacent tunnel magnetoresistance devices TMJ.

However, when the value of β=(h/d) is 0.5, that is, when the distance “d” from the center of the bit line in the width direction to the center of the adjacent bit line in the width direction is 2 times the distance “h” to the center of the second ferromagnetic layer35in the thickness direction, HN(x,h)in the case of x=±1.0, that is, in the second ferromagnetic layer35of the adjacent tunnel magnetoresistance device TMJ, is 0.2. Whether or not this value of HN(x,h)poses a problem depends upon fluctuation of the magnetic field (HEA) in the easy-magnetization axis direction of MRAM and fluctuation of the magnetic field (HHA) in the hard-magnetization axis direction of MRAM in the asteroid curve of MRAM shown inFIG. 38. However, the value has a magnitude that cannot be ignored.

Further, when the value of β=(h/d) is 1.0, that is, when the distance “d” from the center of the bit line in the width direction to the center of the adjacent bit line in the width direction is 1 time the distance “h” to the center of the second ferromagnetic layer35in the thickness direction, HN(x,h)in the case of x=±1.0, that is, in the second ferromagnetic layer35of the adjacent tunnel magnetoresistance device TMJ, comes to be as large as 0.5. When such a magnetic field is generated, it is expectedly difficult to write data stably into a predetermined MRAM even if the fluctuation of the magnetic field (HEA) in the easy-magnetization axis direction of MRAM and the fluctuation of the magnetic field (HHA) in the hard-magnetization axis direction of MRAM can be controlled to be small.

In “Present State and Future View of MRAM” by Yoshiaki SAITO, FIG. 6 shows that when X=0 μm, Hx≈10 Oe, when X=0.2 μm, Hx≈5 Oe, and when X=0.4 μm, Hx≈2 Oe. That is, the value in the case of β=h/d=1.0 in FIG. 40 is more or less correspondent to the data shown in FIG. 6 of “Present State and Future View of MRAM” by Yoshiaki SAITO.

Although it is undeniable that the values differ when boundary conditions, etc., are strictly taken into account, it can be affirmed that even the model depicted by the expression (7) gives a good approximation for the purpose of studying the distribution and magnitude of the magnetic field.

While TMR-type MRAM has an advantage that a higher speed and a higher degree of integration are easily attained as described above, a magnetic field generated during writing data into a certain MRAM may destroy data stored in MRAM adjacent to the above MRAM as discussed above.

For example, JP-A-2002-20388 discloses a means of overcoming the above problem. In the technique disclosed in the above Japanese laid-open patent publication, programming currents (IWL, IBL2) are passed through a word line (WL1) and a bit line (BL2) constituting a memory cell (I2). A compensatory current that provides a compensatory magnetic field to counteract a scattered magnetic field is passed through a word line (PWL) or a bit line (BL3,BL5) constituting at least one memory cell (I3,I5) adjacent to the memory cell (I2).

However, the above Japanese laid-open patent publication describes no specific method or means with regard to what value should be employed for the compensatory current to flow or how the value of the compensatory current to flow should be determined.

Further, the above Japanese laid-open patent publication is silent concerning any specific method of simultaneously writing data in many adjacent MRAMs.

OBJECT AND SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a nonvolatile magnetic memory device having such a constitution that a magnetic field generated during writing of data into a certain tunnel magnetoresistance device does not destroy data stored in a tunnel magnetoresistance device adjacent to the above tunnel magnetoresistance device, and a method of writing data into a tunnel magnetoresistance device in a nonvolatile magnetic memory device, which can prevent an error in writing data even when data are simultaneously written into adjacent many MRAMs.

The nonvolatile magnetic memory device according to a first aspect of the present invention for achieving the above object (more specifically, nonvolatile magnetic memory device having TMR-type MRAM) is a nonvolatile magnetic memory device having a nonvolatile magnetic memory array comprising;

(A) write-in word line(s) that is(are) M (M≧1) in number, extending in a first direction,

(B) bit lines that are N (N≧2) in number, extending in a second direction different from the first direction, and

(C) tunnel magnetoresistance devices, each being formed in an overlap region of the write-in word line and the bit line and having a stacking structure of a first ferromagnetic layer, a tunnel barrier and a second ferromagnetic layer, the first ferromagnetic layer being electrically insulated from the write-in word line, and the second ferromagnetic layer being electrically connected to the bit line,

when data is written into the tunnel magnetoresistance device positioned in the overlap region of the m-th-place write-in word line (m is one of 1, 2, . . . M) and the n-th-place bit line (n is one of 1, 2, . . . N), a current I(m)RWLis passed through (or flowed in) the m-th-place write-in word line and a current g(0)·I(n)BL[g(0):coefficient] is passed through (or flowed in) the n-th-place bit line, and at the same time, a current g(k)·I(n)BL[g(k):coefficient] is passed through (or flowed in) the q-th-place bit line (q=n+k, k is ±1, ±2, . . . , and the total number of the lines is K),

a spatial FIR filter assuming magnetic fields, which are supposed to be formed in the n-th-place bit line and the bit lines that are K in number by the current I(n)BL, to be discrete pulse response and assuming the coefficients g(0) and g(k) to be tap-gains is constituted of the n-th-place bit line and the bit lines that are K in number, and

the coefficients g(0) and g(k) are defined such that data is written into the tunnel magnetoresistance device positioned in the overlap region of the m-th-place write-in word line and the n-th-place bit line and no data are written into the tunnel magnetoresistance devices positioned in the overlap regions of the m-th-place write-in word line and the bit lines that are K in number by means of a synthetic magnetic field based on a magnetic field generated by the current g(0)·I(n)BLflowing in the n-th-place bit line, magnetic fields generated by the currents g(k)·I(n)BLflowing in the bit lines that are K in number, and a magnetic field generated by the current I(m)RWLflowing in the m-th-place write-in word line.

The nonvolatile magnetic memory device according to a second aspect of the present invention for achieving the above object (more specifically, nonvolatile magnetic memory device having TMR-type MRAM) is a nonvolatile magnetic memory device having a nonvolatile magnetic memory array comprising;

(A) write-in word lines that are M (M≧2) in number, extending in a first direction,

(B) bit line(s) that is(are) N (N≧1) in number, extending in a second direction different from the first direction,

(C) tunnel magnetoresistance devices, each being formed in an overlap region of the write-in word line and the bit line and having a stacking structure of a first ferromagnetic layer, a tunnel barrier and a second ferromagnetic layer, the first ferromagnetic layer being electrically insulated from the write-in word line, and the second ferromagnetic layer being electrically connected to the bit line,

when data is written into the tunnel magnetoresistance device positioned in the overlap region of the m-th-place write-in word line (m is one of 1, 2, . . . M) and the n-th-place bit line (n is one of 1, 2, . . . N), a current I(n)BLis passed through (or flowed in) the n-th-place bit line and a current g(0)·I(m)RWL[g(0):coefficient] is passed through (or flowed in) the m-th-place write-in word line, and at the same time, a current g(k)·I(m)RWL[g(k):coefficient] is passed through (or flowed in) the p-th-place write-in word line (p=n+k, k is ±2, ±2, . . . , and the total number of the lines is K),

a spatial FIR filter assuming magnetic fields, which are supposed to be formed in the m-th-place write-in word line and the write-in word lines that are K in number by the current I(m)RWL, to be discrete pulse response and assuming the coefficients g(0) and g(k) to be tap-gains is constituted of the m-th-place write-in word line and the write-in word lines that are K in number, and

the coefficients g(0) and g(k) are defined such that data is written into the tunnel magnetoresistance device positioned in the overlap region of the m-th-place write-in word line and the n-th-place bit line and no data are written into the tunnel magnetoresistance devices positioned in the overlap regions of the n-th-place bit line and the write-in word lines that are K in number by means of a synthetic magnetic field based on a magnetic field generated by the current g(0)·I(m)RWLflowing in the m-th-place write-in word line, magnetic fields generated by the currents g(k)·I(m)RWLflowing in the write-in word lines that are K in number, and a magnetic field generated by the current I(n)BLflowing in the n-th-place bit line.

The method of writing data into a tunnel magnetoresistance device in a nonvolatile magnetic memory device (more specifically, nonvolatile magnetic memory device having TMR-type MRAM), according to a first aspect of the present invention for achieving the above object, is a method of writing data into a tunnel magnetoresistance device in a nonvolatile magnetic memory device having a nonvolatile magnetic memory array comprising;

(A) write-in word line(s) that is(are) M (M≧1) in number, extending in a first direction,

(B) bit lines that are N (N≧2) in number, extending in a second direction different from the first direction, and

(C) tunnel magnetoresistance devices, each being formed in an overlap region of the write-in word line and the bit line and having a stacking structure of a first ferromagnetic layer, a tunnel barrier and a second ferromagnetic layer, the first ferromagnetic layer being electrically insulated from the write-in word line, and the second ferromagnetic layer being electrically connected to the bit line,

when it is assumed that data is written into the tunnel magnetoresistance device positioned in the overlap region of the m-th-place write-in word line (m is one of 1, 2, . . . M) and the n-th-place bit line (n is one of 1, 2, . . . N), a current I(m)RWLis passed through (or flowed in) the m-th-place write-in word line and a current g(0)·I(n)BL[g(0):coefficient] is passed through (or flowed in) the n-th-place bit line, and at the same time, a current g(k)·I(n)BL[g(k):coefficient] is passed through (or flowed in) the q-th-place bit line (q=n+k, k is ±1, ±2, . . . , and the total number of the lines is K),

a spatial FIR filter assuming magnetic fields, which are supposed to be formed in the n-th-place bit line and the bit lines that are K in number by the current I(n)BL, to be discrete pulse response and assuming the coefficients g(0) and g(k) to be tap-gains is constituted of the n-th-place bit line and the bit lines that are K in number, and

the coefficients g(0) and g(k) are defined such that data is written into the tunnel magnetoresistance device positioned in the overlap region of the m-th-place write-in word line and the n-th-place bit line and no data are written into the tunnel magnetoresistance devices positioned in the overlap regions of the m-th-place write-in word line and the bit lines that are K in number by means of a synthetic magnetic field based on a magnetic field generated by the current g(0)·I(n)BLflowing in the n-th-place bit line, magnetic fields generated by the currents g(k)·I(n)BLflowing in the bit lines that are K in number, and a magnetic field generated by the current I(m)RWLflowing in the m-th-place write-in word line,

said method comprising letting the current I(m)RWLflow in the m-th-place write-in word line, and simultaneously letting the following currents i(n)BLflow in each of the first bit line to the N-th-place bit line,

i⁡(n)BL=∑k=-k0k0⁢⁢g⁡(k)·I⁡(n-k)BL(1)
wherein k0is an absolute value of the maximum value that k represents, and k in the expression (1) includes 0.

The method of writing data into a tunnel magnetoresistance device in a nonvolatile magnetic memory device (more specifically, nonvolatile magnetic memory device having TMR-type MRAM), according to a second aspect of the present invention for achieving the above object, is a method of writing data into a tunnel magnetoresistance device in a nonvolatile magnetic memory device having a nonvolatile magnetic memory array comprising;

(A) write-in word lines that are M (M≧2) in number, extending in a first direction,

(B) bit line(s) that is(are) N (N≧1) in number, extending in a second direction different from the first direction,

(C) tunnel magnetoresistance devices, each being formed in an overlap region of the write-in word line and the bit line and having a stacking structure of a first ferromagnetic layer, a tunnel barrier and a second ferromagnetic layer, the first ferromagnetic layer being electrically insulated from the write-in word line, and the second ferromagnetic layer being electrically connected to the bit line,

when it is assumed that data is written into the tunnel magnetoresistance device positioned in the overlap region of the m-th-place write-in word line (m is one of 1, 2, . . . M) and the n-th-place bit line (n is one of 1, 2, . . . N), a current I(n)BLis passed through (or flowed in) the n-th-place bit line and a current g(0)·I(m)RWL[g(0):coefficient] is passed through (or flowed in) the m-th-place write-in word line, and at the same time, a current g(k)·I(m)RWL[g(k):coefficient] is passed through (or flowed in) the p-th-place write-in word line (p=n+k, k is ±1, ±2, . . . , and the total number of the lines is K),

a spatial FIR filter assuming magnetic fields, which are supposed to be formed in the m-th-place write-in word line and the write-in word lines that are K in number by the current I(m)RWL, to be discrete pulse response and assuming the coefficients g(0) and g(k) to be tap-gains is constituted of the m-th-place write-in word line and the write-in word lines that are K in number, and

the coefficients g(0) and g(k) are defined such that data is written into the tunnel magnetoresistance device positioned in the overlap region of the m-th-place write-in word line and the n-th-place bit line and no data are written into the tunnel magnetoresistance devices positioned in the overlap regions of the n-th-place bit line and the write-in word lines that are K in number by means of a synthetic magnetic field based on a magnetic field generated by the current g(0)·I(m)RWLflowing in the m-th-place write-in word line, magnetic fields generated by the currents g(k)·I(m)RWLflowing in the write-in word lines that are K in number, and a magnetic field generated by the current I(n)BLflowing in the n-th-place bit line,

said method comprising letting the current I(n)BLflow in the n-th-place bit line, and simultaneously letting the following currents i(m)RWLflow in each of the first bit line to the M-th-place write-in word line,

i⁡(m)RWL=∑k=-k0k0⁢⁢g⁡(k)·I⁡(m-k)RWL(2)
wherein k0is an absolute value of the maximum value that k represents, and k in the expression (2) includes 0.

In the nonvolatile magnetic memory device according to the first or second aspect of the present invention, or in the method of writing data into a tunnel magnetoresistance device in a nonvolatile magnetic memory device according to the first or second aspect of the present invention, (these will be sometimes generally referred to as “the present invention” hereinafter), the value of I(m)RWLmay be changed depending upon the value of m, or may be constant regardless of the value of m. Further, the value of I(n)BLmay be changed depending upon the value of n, or may be constant regardless of the value of n.

In the present invention, preferably, the coefficients g(0) and g(k) that are assumed to be tap-gains are defined so as to nearly satisfy the Nyquist's first criterion. The Nyquist's first criterion will be described later.

In the present invention, the value of the k can essentially cover values from 1 to an arbitrary positive number. However, the value of k preferably covers values of 1 and 2, for avoiding the complication of driving of the nonvolatile magnetic memory device. In this case, when the absolute value of the maximum value that k represents is k0, the value of k0is 2.

In the nonvolatile magnetic memory device according to the first aspect of the present invention, or in the method of writing data into a tunnel magnetoresistance device in a nonvolatile magnetic memory device according to the first aspect of the present invention, for example, the main magnetic field is generated by the current flowing in the first bit line or the N-th-place bit line [magnetic field generated by the current g(0)·I(1)BLor g(0)·I(N)BL], and the compensatory magnetic fields are generated by the currents flowing in the second, third, . . . bit lines or in . . . , (N−2)-th-place and (N−1)-th-place bit lines [magnetic fields generated by the currents g(k)·I(1)BLor g(k)·I(N)BL]. The compensatory magnetic field is asymmetric, for example, with regard to the first bit line or the N-th-place bit line as a base.

Therefore, in the nonvolatile magnetic memory device according to the first aspect of the present invention, or in the method of writing data into a tunnel magnetoresistance device in a nonvolatile magnetic memory device according to the first aspect of the present invention, when the absolute value of the maximum value of the values that the k represents is k0,

a group of first dummy line(s) that is(are) k0in number is provided outside the first bit line and in parallel with the first bit line,

a group of second dummy line(s) that is(are) k0in number is provided outside the N-th-place bit line and in parallel with the N-th-place bit line, and

the current g(k)·I(n)BLis passed through (or flowed in) a [(1−n)+|k|]-th-place first dummy line constituting the group of the first dummy line(s) or an [n−N+|k|]-th-place second dummy line constituting the group of the second dummy line(s), which is preferred for preventing the magnetic field from being asymmetrical, for example, with regard to the first bit line or the N-th-place bit line as a base.

In this case, the value of the k can essentially cover values from 1 to an arbitrary positive number. However, the value of k preferably covers values of 1 and 2, for avoiding the complication of driving of the nonvolatile magnetic memory device. In this case, the value of k0is 2.

In the nonvolatile magnetic memory device according to the second aspect of the present invention, or in the method of writing data into a tunnel magnetoresistance device in a nonvolatile magnetic memory device according to the second aspect of the present invention, the main magnetic field is generated by the current flowing in the first write-in word line or the M-th-place write-in word line [magnetic field generated by the current g(0)·I(1)RWLor current g(0)·I(M)RWL], and the compensatory magnetic fields are generated by the currents flowing in the second, third, . . . write-in word lines or in . . . , (M−2)-th-place and (M−1)-th-place write-in word lines [magnetic fields generated by the currents g(k)·I(1)RWLor g(k)·I(M)RWL]. The compensatory magnetic field is asymmetric, for example, with regard to the first write-in word line or the M-th-place write-in word line as a base.

Therefore, in the nonvolatile magnetic memory device according to the second aspect of the present invention, or in the method of writing data into a tunnel magnetoresistance device in a nonvolatile magnetic memory device according to the second aspect of the present invention, when the absolute value of maximum value of values that the k represents is k0,

a group of first dummy line(s) that is(are) k0in number is provided outside the first write-in word line and in parallel with the first write-in word line,

a group of second dummy line(s) that is(are) k0in number is provided outside the M-th-place write-in word line and in parallel with the M-th-place write-in word line, and

the current g(k)·I(m)RWLis passed through (or flowed in) a [(1−m)+|k|]-th-place first dummy line constituting the group of the first dummy line(s) or an [m−M+|k|]-th-place second dummy line constituting the group of the second dummy line(s), which is preferred for preventing the magnetic field from being asymmetrical, for example, with regard to the first write-in word line or the M-th-place write-in word line as a base.

In this case, the value of the k can as well essentially cover values from 1 to an arbitrary positive number. However, the value of k preferably covers values of 1 and 2, for avoiding the complication of driving of the nonvolatile magnetic memory device. In this case, the value of k0is 2.

In the present invention, specific values of N include 8 and 16, and specific values of M include 16, 32 and 64.

In the present invention, preferably, the first ferromagnetic layer more specifically has a two-layer structure of an anti-ferromagnetic layer and a ferromagnetic layer (called a reference layer or a pinned magnetic layer as well), whereby the first ferromagnetic layer can have an intense unidirectional magnetic anisotropy due to an exchange interaction working between these two layers. The pinned magnetic layer is in contact with the tunnel barrier. The second ferromagnetic layer of which the magnetization direction relatively easily rotates is also called a free layer or a memory layer. The tunnel barrier works to disconnect a magnetic coupling between the second ferromagnetic layer (memory layer) and the pinned magnetic layer, and a tunnel current flows in the tunnel barrier.

The insulating material for constituting the tunnel barrier includes an aluminum oxide (AlOx), an aluminum nitride (AlN), a magnesium oxide (MgO), a magnesium nitride, a silicon oxide and a silicon nitride. Further, it also includes Ge, NiO, CdOx, HfO2, Ta2O5, BN and ZnS. The tunnel barrier can be obtained, for example, by oxidizing or nitriding a metal film formed by a sputtering method. More specifically, when an aluminum oxide (AlOx) is used as an insulating material for constituting the tunnel barrier, the method for forming the tunnel barrier includes a method in which aluminum formed by a sputtering method is oxidized in atmosphere, a method in which aluminum formed by a sputtering method is plasma-oxidized, a method in which aluminum formed by a sputtering method is oxidized with IPC plasma, a method in which aluminum formed by a sputtering method is subject to natural oxidation in oxygen gas, a method in which aluminum formed by a sputtering method is oxidized with oxygen radicals, a method in which aluminum formed by a sputtering method is irradiated with ultraviolet rays while it is subjected to natural oxidation in oxygen gas, a method in which aluminum is formed by a reactive sputtering method, and a method in which an aluminum oxide is formed by a sputtering method. Alternatively, the tunnel barrier can be formed by a CVD method typified by an ALD method.

The stacking structure can be patterned, for example, by a reactive ion etching (RIE) method or an ion milling method. They can be also patterned by a so-called lift-off method as required.

The write-in word line, the bit line or the dummy line is composed, for example, of aluminum, an aluminum alloy such as Al—Cu, or copper (Cu), and it can be formed, for example, by a PVD method such as a sputtering method, a CVD method, or a plating method typified by an electrolytic plating method.

Although not limited, the nonvolatile magnetic memory device in the present invention may have a constitution in which the nonvolatile magnetic memory device comprises;

(a) a transistor for selection which is formed in a semiconductor substrate,

(b) a first insulating interlayer which covers the transistor for selection,

(c) a second insulating interlayer, and

(d) a third insulating interlayer,

in which the write-in word line is formed on the first insulating interlayer,

the second insulating interlayer covers the write-in word line and the first insulating interlayer,

the first ferromagnetic layer is formed on the second insulating interlayer,

the third insulating interlayer covers the tunnel magnetoresistance device and the second insulating interlayer,

an extended portion of the first ferromagnetic layer or a lead-out electrode extending from the first ferromagnetic layer on the second insulating interlayer is electrically connected to the transistor for selection through connecting holes (or connecting holes and a landing pad) provided in the second and first insulating interlayers, and

the bit line is formed on the third insulating interlayer.

The connecting hole can be constituted of a polysilicon doped with an impurity, and a refractory metal or metal silicide such as W, Ti, Pt, Pd, Cu, TiW, TiNW, WSi2or MoSi2. It can be formed by a chemical vapor deposition method (CVD method), or a PVD method such as a sputtering method.

The transistor for selection can be constituted, for example, of a well-known MIS-type FET or MOS-type FET or a bipolar transistor.

In the nonvolatile magnetic memory device according to the first aspect of the present invention, or in the method of writing data into a tunnel magnetoresistance device in a nonvolatile magnetic memory device according to the first aspect of the present invention, the coefficients g(0) and g(k) are defined such that data is written into the tunnel magnetoresistance device positioned in the overlap region of the m-th-place write-in word line and the n-th-place bit line and no data are written into the tunnel magnetoresistance devices positioned in the overlap regions of the m-th-place write-in word line and the bit lines that are K in number by means of the synthetic magnetic field based on the magnetic field (to be referred to as “main magnetic field”) generated by the current g(0)·I(n)BLflowing in the n-th-place bit line, the magnetic fields (to be referred to as “compensatory magnetic fields”) generated by the currents g(k)·I(n)BLflowing in the bit lines that are K in number, and the magnetic field generated by the current I(m)RWLflowing in the m-th-place write-in word line. Meanwhile, the spatial FIR filter assuming the magnetic fields, which are supposed to be formed in the n-th-place bit line and the bit lines that are K in number by the current I(n)BL, to be discrete pulse response and assuming the coefficients g(0) and g(k) to be tap-gains (to be also called “filter coefficient” or “tap coefficient”) is constituted of the n-th-place bit line and the bit lines that are K in number.

In the nonvolatile magnetic memory device according to the second aspect of the present invention, or in the method of writing data into a tunnel magnetoresistance device in a nonvolatile magnetic memory device according to the second aspect of the present invention, the coefficients g(0) and g(k) are defined such that data is written into the tunnel magnetoresistance device positioned in the overlap region of the m-th-place write-in word line and the n-th-place bit line and no data are written into the tunnel magnetoresistance devices positioned in the overlap regions of the n-th-place bit line and the write-in word lines that are K in number by means of the synthetic magnetic field based on the magnetic field (main magnetic field) generated by the current g(0)·I(m)RWLflowing in the m-th-place write-in word line, the magnetic fields (compensatory magnetic fields) generated by the currents g(k)·I(m)RWLflowing in the write-in word lines that are K in number, and the magnetic field generated-by the current I(m)RWLflowing in the n-th-place bit line. Meanwhile, the spatial FIR filter assuming the magnetic fields, which are supposed to be formed in the m-th-place write-in word line and the write-in word lines that are K in number by the current I(m)RWL, to be discrete pulse response and assuming the coefficients g(0) and g(k) to be tap-gains is constituted of the m-th-place write-in word line and the write-in word lines that are K in number.

In the present invention, therefore, the coefficients g(0) and g(k) can be relatively easily obtained on the basis of a known calculation method in which an amplitude error between the intended property (for example, property satisfying the Nyquist's first criterion) and the filter output in the FIR filter is minimized. The above calculation methods includes well-known methods such as a method of designing a Wiener filter, a calculation method using a least-mean-square (LMS) algorism, a calculation method using a recursive least-mean-square (RLS) algorism, a calculation method using a steepest decent algorism and a calculation method using a learning identification method.

And, the coefficients g(0) and g(k) are defined, whereby erroneous data writing into an adjacent tunnel magnetoresistance device can be reliably prevented, and as a result, data can be simultaneously written into the adjacent tunnel magnetoresistance devices.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Prior to the explanation of the nonvolatile magnetic memory device and the method of writing data into a tunnel magnetoresistance device in a nonvolatile magnetic memory device provided by the present invention, first, an example in which a magnetic field (main magnetic field) is generated by a current g(n)·I(n) [g(0):coefficient] flowing in an n-th-place write-in conductor line (bit line or write-in word line) and magnetic fields (compensatory magnetic fields) are generated by currents g(k)·I(n) [g(k):coefficient] flowing in q-th-place write-in conductor lines (q=n+k, k is ±1, ±2, . . . , total number of the write-in conductor lines is K, and K=2k0when the absolute value of the values that k represents is k0) will be explained with regard to a constitution in which a spatial FIR filter assuming magnetic fields, which are supposed to be formed in the n-th-place write-in conductor line and the q-th-place write-in conductor lines by the current I(n), to be discrete pulse response and assuming the coefficients g(0) and g(k) to be tap-gains is constituted of the n-th-place write-in conductor line and the write-in conductor lines that are K in number (that is, the write-in conductor lines that are k0in number are arranged on one side of the n-th-place write-in conductor line, and the write-in conductor lines that are k0in number are arranged on the other side of the n-th-place write-in conductor line). A time-domain FIR filter will be explained beforehand.

FIG. 41shows a constitution of a digital transmission system using a time-domain FIR filter. A received signal a(j) in the digital transmission system represents ±1, and it represents 0 when none is transmitted. The received signal a(j) received in the digital transmission system is mostly AD-converted with a data rate clock to be converted to a discrete received signal x(α). The x(α) is a received signal before equalization and is a signal formed by linearly superimposing a product of the received signal a(j) and a pulse response function (transmission function) upr(α) of the digital transmission system. It can be represented by the following expression (8). “α” is an integer representing a discrete time on a receiving side, and j is an integer representing a discrete time on a transmission side.

When the received signal x(α) before equalization passes through the FIR filter, a received signal y(α) after equalization is obtained. The received signal y(α) is a signal obtained by linearly superimposing a product of the tap-gain (g) of the FIR filter and x(α), and can be represented by the following expressions (9-1) and (9-2).

FIG. 42shows a constitution example of a time-domain FIR filter. The discrete received signals x(α) before equalization sampled at the time intervals of T are inputted into delay elements FF (composed of flip-flops) having (2|K0|+1) stages, the outputs from the delay elements FF are multiplied by the tap-gain g(k), and the products are added up, whereby the received signal y(α) after equalization can be obtained.

FIG. 42shows a case where |k0|=2. That is, a FIR filter with five taps is shown, and when the received signals x(α) before equalization are inputted, the output represented by the following expression (10) is obtained.

A delay of time of T corresponds to exp(jwT) in frequency characteristic, so that the frequency characteristic of x(α) can be changed in various ways, and the output (received signal y(α) after equalization) having a desired waveform can be obtained although it depends upon the value of length [2(|k0|+1)] of the tap.

A pulse that represents “1” only for a time period of one clock and represents “0” for other time period like “. . . 00010000 . . . ” will be referred to as “unit pulse” in the present specification. A response when a digital transmission system shown, for example, inFIG. 41receives the unit pulse will be referred to as “pulse response”. This is a substitute for an impulse response in an analog transmission system. When the digital transmission system receives the unit pulse shown inFIG. 43A, for example, the pulse response shown inFIG. 43Bis obtained.

Adjustment to a predetermined waveform with the time-domain FIR filter is referred to as equalization. In the simplest example of the equalization, the waveform is equalized so as to approximate to the Nyquist's first criterion as shown inFIG. 44. The Nyquist's first criterion means that the amplitude every T that is a sampling time cycle is so defined that the presence of a pulse represents “1” and that any other case represents “0”.

The tap-gain g(k) of the time-domain FIR filter can be obtained on the basis of a calculation method in which the amplitude difference between the intended characteristic (Nyquist's first criterion) and the filter output is minimized. The above calculation method includes well-known calculation methods such as a method of designing a Wiener filter, a calculation method using a least-mean-square (LMS) algorithm, a calculation method using a recursive least-mean-square (RLS) algorithm, a calculation method using a steepest descent algorithm and a calculation method using a learning identification method.

Tap-gains g(k) in a 3-tap FIR filter, a 5-tap FIR filter and a 7-tap FIR filter, calculated by a method of designing a Wiener filter, are as shown in the following Tables 1, 2 and 3.

When it is assumed that the digital transmission system shown inFIG. 41receives data of “0, 0, 0, 0, −1, +1, −1, −1, +1, +1, −1, +1, 0, 0, 0, 0”, the transmission data will be as illustrated inFIG. 45A. In this case, if the transmission characteristic is the same as the transmission characteristic shown inFIG. 43B, the pulse response at a time when transmission data is “+1” has the waveform shown inFIG. 43B, and the pulse response at a time when transmission data is “−1” has a waveform obtained by inverting the waveform shown inFIG. 43B. A received signal x(α) before equalization shown inFIG. 45Bis obtained by superimposing such waveforms of these pulse responses. When the received signal x(α) before equalization passes through the FIR filter, the received signal y(α) after equalization as shown inFIG. 46is obtained. The received signal y(α) after equalization is a signal equalized so as to approximate to the Nyquist's first criterion, so that the transmitted data is “+1” at a time of “+1”, “−1” at a time of “−1”, and “0” at a time of “0”. An original transmission data can be therefore easily restored with a discrimination circuit.

FIG. 4is a drawing for explaining it on the basis of preliminary knowledge on the time-domain FIR filter used in the digital transmission shown inFIGS. 41 to 46, that the write-in conductor lines (bit lines or write-in word lines) of the tunnel magnetoresistance device constitute the spatial FIR filter.

It is assumed that the write-in conductor lines, that are (2k0+1) in number and have an indefinite length, are arranged in points of (d·k,0) [k is ±1, ±2, . . . ] and in parallel at a distance of “d”, and that a current I(0) is passed only through the k-th-place write-in conductor line. The magnetic fields HX(0,h)kand HY(0,h)kin the X-axis and Y-axis directions at a point of (0,h) can be determined on the basis of the following expressions (11-1) and (11-2) derived from the expressions (3-1) and (3-2).
HX(0,h)k=I(0)·{sin(θ0,k)/2τr0,k}  (11-1)
HY(0,h)k=I(0)·{−cos(θ0,k)/2πr0,k}  (11-2)

Further, when the current I(0) flows in all of the parallel write-in conductor lines that are (2k0+1) in number, the magnetic fields H′X(0,h)SUMand H′Y(0,h)SUMin the X-axis and Y-axis directions at the point of (0,h) can be determined on the basis of the following expressions (12-1) and (12-2), provided that k0is an absolute value of the maximum value that k represents.

Meanwhile, when it is supposed that the current I(0) flows only in the 0-place write-in conductor line in the parallel write-in conductor lines that are (2k0+1) in number (this state corresponds to the above-described unit pulse), the magnetic field in this case is as shown inFIG. 40. This magnetic field corresponds to the pulse response that has been already explained and is shown inFIG. 43B. Further, this magnetic field also corresponds to x(α−0) in the expression (9-1) or x(α) shown inFIG. 42. When it is supposed that the current I(0) flows only in the k-th-place write-in conductor line in the parallel write-in conductor lines that are (2k0+1) in number, the magnetic field in this case corresponds to x(α−k) in the expression (9-1) or x(α−k) shown inFIG. 42. Therefore, the magnetic fields that are supposed to be formed in the 0-place write-in conductor line and the write-in conductor lines that are 2k0by the current I(0) can be regarded as discrete pulse response.

When a current g(0)·I(0) obtained by multiplying the current I(0) by a proper coefficient g(0) is passed through (or flowed in) the 0-place write-in conductor line and when a current g(k)·I(0) obtained by multiplying the current I(0) by a proper coefficient g(k) is passed through (or flowed in) the k-th-place write-in conductor line, the magnetic fields HX(0,h)SUMand HY(0,h)SUMin the X-axis and Y-axis directions at the point of (0,h) can be determined on the basis of the following expressions (13-1) and (13-2), provided that k0is an absolute value of the maximum value that k represents.

Meanwhile, since the magnetic fields, that are supposed to be formed in the 0-place write-in conductor line and the write-in conductor lines that are 2k0in number by the current I(0), can be regarded as discrete pulse response, the coefficients g(0) and g(k) in the expressions (13-1) and (13-2) correspond to tap-gains. Ultimately, it can be said that the spatial FIR filter assuming magnetic fields, which are supposed to be formed in the 0-place write-in conductor line and the write-in conductor lines that are 2k0in number by the current I(0), to be discrete pulse response and assuming the coefficients g(0) and g(k) to be tap-gains is constituted of the 0-place write-in conductor line and the write-in conductor lines that are 2k0in number.

If the coefficients g(0) and g(k) are defined so as to nearly satisfy the Nyquist's first criterion, that is, if the coefficients g(0) and g(k) are defined such that when it is supposed that the current I(0) flows in the k-th-place write-in conductor line [position coordinates:(d·k,0)], the magnetic field at a point of (d·k,h) is a predetermined value H0or an approximate value to the predetermined value H0, that when it is supposed that the current I(0) does not flow in the k-th-place write-in conductor line, the magnetic field at the point of (d·k,h) is a value of 0 or an approximate value to 0, and that when it is supposed that the current −I(0) flows in the k-th-place write-in conductor line, the magnetic field in the point of (d·k,h) is a predetermined value −H0or an approximate value to the predetermined value −H0, the occurrence of erroneous data writing can be reliably prevented when data are written into the tunnel magnetoresistance devices in the nonvolatile magnetic memory device to be described below.

More specifically, it is sufficient to define the coefficients g(0) and g(k) such that;

[A] when it is supposed that the current I(n)BLis passed through (or flowed in) the n-th-place (n=1, 2, . . . N) bit line in the bit lines that are N in number and arranged side by side at a distance of “d”, the magnetic field generated in the second ferromagnetic layer (memory layer or free layer) of the tunnel magnetoresistance device electrically connected to the n-th-place bit line by the current I(N)BLhas a predetermined value H0or an approximate value to the predetermined value H0,

[B] when it is supposed that the current I(n)BLis not passed through (or flowed in) the n-th-place bit line, the magnetic field, due to such a current I(n)BL, in the second ferromagnetic layer of the tunnel magnetoresistance device electrically connected to the n-th-place bit line has a value of 0 or an approximate value to 0, and

[C] when it is supposed that the current −I(n)BLis passed through (or flowed in) the n-th-place bit line, the magnetic field generated in the second ferromagnetic layer of the tunnel magnetoresistance device electrically connected to the n-th-place bit line by the current −I(n)BLhas a predetermined value −H0or an approximate value to the predetermined value −H0.

Alternatively, more specifically, it is sufficient to define the coefficients g(0) and g(k) such that;

[A] when it is supposed that the current I(m)RWLis passed through (or flowed in) the m-th-place (m=1, 2, . . . M) write-in word line in the write-in word lines that are M in number and arranged side by side at a distance of “d”, the magnetic field generated in the second ferromagnetic layer (memory layer or free layer) of the tunnel magnetoresistance device opposed to the m-th-place write-in word line by the current I(m)RWLhas a predetermined value H′0or an approximate value to the predetermined value H′0,

[B] when it is supposed that the current I(m)RWLis not passed through (or flowed in) the m-th-place write-in word line, the magnetic field, due to such a current I(m)RWL, in the second ferromagnetic layer of the tunnel magnetoresistance device opposed to the m-th-place write-in word line has a value of 0 or an approximate value to 0, and

[C] when it is supposed that the current −I(m)RWLis passed through (or flowed in) the m-th-place write-in word line, the magnetic field generated in the second ferromagnetic layer of the tunnel magnetoresistance device opposed to the m-th-place write-in word line by the current −I(n)RWLhas a predetermined value −H′0or an approximate value to the predetermined value −H′0.

In the example shown inFIG. 4, five write-in conductor lines are present, a write-in current g(k)·I(0) flows in the k-th-place write-in conductor line (k is 0, ±1, ±2). InFIG. 4, the current I(0) is shown as “I”. The magnetic fields HX(d·s,h)SUMand HY(d·s,h)SUMin the X-axis and Y-axis directions at a point (d·s,h) where the memory layer of the s-th-place tunnel magnetoresistance device (“s” is one of −2, −1, 0, 1, 2) is positioned, generated by the current flowing in the k-th-place write-in conductor line, can be determined on the basis of the expressions (14-1) and (14-2). “k0” is an absolute value of the maximum value that k represents, and in the example shown inFIG. 4, k0=2. Further, inFIG. 4, the magnetic fields HX(d·s,h)SUMand HY(d·s,h)SUMare shown as HXn(s) and HYn(s) for convenience.

As described above, the spatial FIR filter is supposed to be constituted of the five write-in conductor lines. That is, it is supposed that the spatial FIR filter assuming the magnetic fields, which are supposed to be formed in the 0-place write-in conductor line and the write-in conductor lines that are 2k0in number by the current I(0), to be discrete pulse response (seeFIG. 40) and assuming the coefficients g(0) and g(k) to be tap-gains is constituted of the 0-place write-in conductor line and the write-in conductor lines that are 2k0in number, two of which are arranged on one side of the 0-place write-in conductor line and the balanced two of which are arranged on the other side the 0-place write-in conductor line.FIG. 2shows the write-in currents (normalized write-in currents) when the currents g(0)·I(0) and g(k)·I(0) in proportion of the coefficients (tap-gains) g(0) and g(k) are passed through (or flowed in) the write-in conductors such that the magnetic fields generated in the positions where the tunnel magnetoresistance devices other the 0-place tunnel magnetoresistance device are positioned are made to be as small as possible. In this case, the currents flowing in the write-in conductor lines are adjusted so as to approximate to the Nyquist's first criterion as are shown inFIG. 44. Specifically, the coefficients (tap-gains) g(0) and g(k) are adjusted to the values shown in Table 2.

In this case, when the current g(0)·I(0) is passed through (or flowed in) the 0-place write-in conductor line, the magnetic field HN(0,h)in the X-axis direction in the point (0,h) where the 0-place tunnel magnetoresistance device is positioned is determined on the basis of the following expression based on the expression (7), andFIG. 1shows the result by a solid line g(0)·I. The unit in the axis of abscissas is “d”. Further, β=(h/d)=1.0.
HN(0,h)=g(0)·β2/(x2+β2)  (7-A)

Further, when the current g(0)·I(Q) is passed through (or flowed in) the first write-in conductor line, the magnetic field HN(d,h)in the X-axis direction in a point (d,h) where the first tunnel magnetoresistance device is positioned is determined on the basis of the following expression based on the expression (7), andFIG. 1shows the result by a dotted line g(1)·I.
HN(d,h)=g(1)·β2/{(x−1)2+β2}  (7-B)

Further, when the current g(−1)·I(0) is passed through (or flowed in) the (−1)-place write-in conductor line, the magnetic field HN(−d,h)in the X-axis direction in a point (−d,h) where the (−1)-place tunnel magnetoresistance device is positioned is determined on the basis of the following expression based on the expression (7), andFIG. 1shows the result by a dotted line g(−1)·I.
HN(−d,h)=g(−1)·β2/{(x+1)2+β2}  (7-C)

Further, when the current g(2)·I(0) is passed through (or flowed in) the second write-in conductor line, the magnetic field HN(2d,h)in the X-axis direction in a point (−2d,h) where the second tunnel magnetoresistance device is positioned is determined on the basis of the following expression based on the expression (7), andFIG. 1shows the result by a solid line g(2)·I.
HN(2d,h)=g(2)·β2/{(x−2)2+β2}  (7-D)

Further, when the current g(−2)·I(0) is passed through (or flowed in) the (−2)-place write-in conductor line, the magnetic field HN(−2d,h)in the X-axis direction in a point (−2d,h) where the (−2)-place tunnel magnetoresistance device is positioned is determined on the basis of the following expression based on the expression (7), andFIG. 1shows the result by a solid line g(−2)·I.
HN(−2d,h)=g(−2)·β2/{(x+2)2+β2}  (7-E)

InFIG. 1, a thick solid line g·I shows a graph obtained by superimposing the magnetic fields HN(0,h), HN(d,h), HN(−d,h), HN(2d,h)and HN(−2d,h), that is, a graph of the value HN(x,h)SUMbased on the expression (16) which normalizes the magnetic field H (X,H) in the X-axis direction determined on the basis of the following expression (15) obtained by commonizing the expression (14-1).

As is clear fromFIG. 1, in any tunnel magnetoresistance device other than the 0-place tunnel magnetoresistance device where data is to be written, the magnitude of the magnetic field in the X-axis direction is almost zero.

Similarly, when it is supposed that three and seven write-in conductor lines constitute spatial FIR filters, the values HN(x,h)SUMbased on the expression (16) which normalizes the magnetic fields H(X,h) in the X-axis direction obtained by the expression (15) are as shown inFIGS. 3A and 3B. The unit of the axis of abscissas in each ofFIGS. 3A and 3Bis “d”. In these cases, the currents flowing in the write-in conductor lines are adjusted so as to approximate to the Nyquist's first criterion as similarly as shown inFIG. 44. Specifically, the coefficients (tap-gains) g(0) and g(k) are determined as shown in Tables 1 and 3. Further, β=(h/d)=1.0. As are clear fromFIGS. 3A and 3B, in any tunnel magnetoresistance device other than the 0-place tunnel magnetoresistance device where data is to be written, the magnitude of the magnetic field in the X-axis direction is almost zero.

The following Table 4 shows the values of tap-gains g(0) and g(k) when the value of β=h/d is 0.1, 0.5 and 1.0 and three write-in conductor lines are regarded as a spatial FIR filter.

On the basis of the above explanations, the present invention will be explained below with reference to drawings and on the basis of Examples.

Example 1 is concerned with the nonvolatile magnetic memory device according to the first aspect of the present invention.FIG. 5shows a schematic partial cross-sectional view of a TMR-type tunnel magnetoresistance device TMJ in Example 1,FIG. 6shows an equivalent circuit diagram of the nonvolatile magnetic memory device, andFIG. 7shows an equivalent circuit diagram of one TMR-type tunnel magnetoresistance device TMJ. InFIGS. 6,8,11,17,33to35and37, showing of an equivalent circuit of a transistor for selection TR is omitted. Further, the cross-sectional structure and the equivalent circuit diagram of one TMR-type tunnel magnetoresistance device TMJ can be similarly employed in Examples 2 to 10 to be described later.

One tunnel magnetoresistance device TMJ in Example 1 has a stacking structure of a first ferromagnetic layer31, a tunnel barrier34made of AlOxand a second ferromagnetic layer35(also called a free layer or a memory layer) made of an Ni—Fe alloy which are positioned in this order from below. More specifically, the first ferromagnetic layer31has a two-layer structure of an anti-ferromagnetic layer32made of an Fe—Mn alloy and a pinned magnetic layer33made of an Ni—Fe alloy which are positioned in this order from below. The pinned magnetic layer33has its magnetization direction pinned by an exchange coupling with the anti-ferromagnetic layer32. Due to an externally applied magnetic field (synthetic magnetic field described above), the magnetization direction of the second ferromagnetic layer (memory layer)35is changed to the direction in parallel or antiparallel with the magnetization direction of the pinned magnetic layer33. The first ferromagnetic layer31is electrically insulated from the write-in word line RWL through a second insulating interlayer24. The write-in word line RWL extends in a first direction (direction perpendicular to the paper surface of the drawing). The second ferromagnetic layer35is electrically connected to the bit line BT through a top coating film36formed of copper (Cu), tantalum (Ta), TiN or the like. The top coating film36works to prevent mutual diffusion of atoms constituting the bit line BL and atoms constituting the ferromagnetic layer (memory layer)35, to reduce a contact resistance and to prevent the oxidation of the ferromagnetic layer (memory layer)35. A third insulating interlayer26covers the tunnel magnetoresistance device TMJ and the second insulating interlayer24. The bit line BL is formed on the third insulating interlayer26and extends to a second direction (right and left direction of the paper surface of the drawing) different from the first direction. InFIG. 5, reference numeral37indicates a lead-out electrode connected to the lower surface of the anti-ferromagnetic layer32.

The transistor for selection TR constituted of a MOS-type FET is formed in a semiconductor substrate10. More specifically, the transistor for selection TR is formed in an active region surrounded by a device isolation region11, and comprises a gate electrode12, a gate insulating film13and source/drain regions14A and14B. The first insulating interlayer21made, for example, of SiO2covers the transistor for selection TR. The first connecting hole22made of a tungsten plug is formed in a first opening portion formed through the first insulating interlayer21, and is connected to one source/drain region14B of the transistor for selection TR. The first connecting hole22is further connected to a landing pad23formed on the first insulating interlayer21. The write-in word line RWL made of Al—Cu alloy is also formed on the first insulating interlayer21. The second insulating interlayer24is formed on the write-in word line RWL and the first insulating interlayer21. The lead-out electrode37is formed on the second insulating interlayer24, and is connected to the landing pad23through a second connecting hole25made of a tungsten plug formed through the second insulating interlayer24. The other source/drain region14A of the transistor for selection TR is connected to a sense line16through a contact hole15.

There are some cases where the transistor for selection TR is not required.

As shown inFIG. 6, the nonvolatile magnetic memory device in Example 1 has a nonvolatile magnetic memory array comprising;

(A) the write-in word lines RWLmthat are M in number (m=1, 2, . . . M, M≧1 and M=32 in Example 1), extending in a first direction,

(B) the bit lines BLnthat are N in number (n=1, 2, . . . N, N≧2 and N=8 in Example 1), extending in a second direction different from the first direction, and

(C) the tunnel magnetoresistance devices TMJ described above that are N×M (=8×32) in number, each of which forms in the overlap region of the write-in word line RWLmand the bit line BLn.

When data is written into the tunnel magnetoresistance device TMJ(m,n)positioned in the overlap region of the m-th-place write-in word line RWLm(m is one of 1, 2, . . . M) and the n-th-place bit line BLn(n is one of 1, 2, . . . N), a current I(m)RWLis passed through (or flowed in) the m-th-place write-in word line RWLm, a current g(0)·I(n)BLis passed through (or flowed in) the n-th-place bit line BLn[g(0):coefficient], and a current g(k)·I(n)BL[g(k):coefficient] is passed through (or flowed in) the q-th-place bit line BLq(q=n+k, k represents ±1, ±2, . . . , k, and in Example 1, represents a value of −2, −1, 1, 2, and the total number of the lines is K).

When the magnetic fields, which are supposed to be formed in the n-th-place bit line BLnand the bit lines BLqthat are K in number by the current I(n)BL, are assumed to be discrete pulse response, and when the coefficients g(0) and g(k) are assumed to be tap-gains, a spatial FIR filter is constituted of the n-th-place bit line BLnand the bit lines BLqthat are K in number.

Further, the coefficients g(0) and g(k) are defined such that data is written into the tunnel magnetoresistance device TMJ(m,n)positioned in the overlap region of the m-th-place write-in word line RWLmand the n-th-place bit line BLnand no data are written into the tunnel magnetoresistance devices TMJ(m,q)positioned in the overlap regions of the m-th-place write-in word line and the bit lines BLqthat are K in number by the synthetic magnetic field based on the magnetic field (main magnetic field) generated by the current g(0)·I(n)BLflowing in the n-th-place bit line BLn, the magnetic fields (compensatory magnetic fields) generated by the currents g(k)·I(n)BLflowing in the bit lines BLqthat are K in number, and the magnetic field generated by the current I(m)RWLflowing in the m-th-place write-in word line.

When the value of k represents ±1 and ±2 as examples, and when a simple model inFIG. 39is used for approximation, the values of g(−2), g(−1), g(0), g(1) and g(2) when β=(h/d)=1.0 are as shown in Table 2. The absolute value k0of the maximum value that k represents is 2. Further, the value of n and the value of K have a relationship as shown in the following Table 5.

The value of I(m)RWLmay be changed depending upon the value of m, and the value of I(n)BLmay be changed depending upon the value of n, while Examples 1 to 10 use a constant value as the value of I(m)RWLregardless of the value of m, and use a constant value as the value of I(N)BLregardless of the value of n. The value of a constant I(n)RWLis expressed as IRWL, and the value of a constant |I(n)BL| is expressed as IBL.

Meanwhile, the value of g(−2) and the value of g(2) are the same, and the value of g(−1) and the value of g(1) are the same. In the following explanation, therefore, the current source for letting the current g(−1)·IBLflow and the current source for letting the current g(1)·IBLflow are constituted of one current source, and the current source for letting the current g(−2)·IBLflow and the current source for letting the current g(2)·IBLflow are constituted of one current source. This will be also applicable to Examples 2 to 5.

That is, the bit line BLnis provided with a current source unit BCSnfor letting the current ±g(0)·I(n)BL[more specifically, the current g(0)·I(n)BLand the current −g(0)·I(n)BL], the current ±g(±1)·I(n)BL[more specifically, the current g(±1)·IBLand the current −g(±1)·IBL] and the current ±g(±2)·I(n)BL[more specifically, the current (±2)·IBLand the current −g(±2)·IBL] flow in the bit lines BLn.

The current source unit BCSnis provided with open/close circuits SWBLn−i(i=1,2,3,4,5,6) constituted of a MOS-type FET each, and one of six currents, the current g(0)·IBL, the current −g(0)·IBL, the current g(±1)·IBL, the current −g(±1)·IBL, the current g(±2)·IBLand the current −g(±2)·IBL, can be passed through (or flowed in) the bit line BLnfrom the current source unit BCSnby the ON/OFF operation of the open/close circuits SWBLn−i.FIG. 6shows the current source unit BCS4connected to the fourth bit line BL4, while other current source units BCS1to BCS3and BCS5to BCS8have the same constitution as that of the current source unit BCS4.

The current source units and a dummy line current source unit, a bit line current source unit and a write-in word line current source unit to be described later can have known circuit constitutions, and the switch circuit and the open/close circuit can be constituted, for example, of a MOS-type FET.

The current g(0)·IBLor the current −g(0)·IBLis a current (to be sometimes referred to as “main magnetic field generating current ±g(0)·IBL”) for generating a magnetic field for writing data into the tunnel magnetoresistance devices, that are M in number, (tunnel magnetoresistance device TMJ(1,n)−tunnel magnetoresistance devices TMJ(M,n)) electrically connected to the n-th-place bit line BLn.

The current g(±1)·IBLor the current −g(±1)·IBLis a compensatory current (to be sometimes referred to as “first compensatory magnetic field generating current ±g(±1)·IBL”) for generating the compensatory magnetic field for preventing the destruction of data stored in the tunnel magnetoresistance devices (tunnel magnetoresistance device TMJ(1,n)−tunnel magnetoresistance device TMJ(M,n)) electrically connected to the n-th-place bit line BLn, which destruction is caused by the magnetic field generated as a result of the flowing of the main magnetic field generating current ±g(0)·IBLin the bit line BLn. when data are written into the tunnel magnetoresistance devices (tunnel magnetoresistance device TMJ(1,n′)—tunnel magnetoresistance device TMJ(M,n′)) electrically connected to the bit line BLn′[n′=n±1, and 2≦n′≦(N−1)] adjacent to the n-th-place bit line BLn.

Further, the current g(±2)·IBLor the current −g(±2)·IBLis a compensatory current (to be sometimes referred to as “second compensatory magnetic field generating current ±g(±2)·IBL”) for generating the compensatory magnetic field for preventing the destruction of data stored in the tunnel magnetoresistance devices (tunnel magnetoresistance device TMJ(1,n)−tunnel magnetoresistance device TMJ(M,n)) electrically connected to the n-th-place bit line BLn, which destruction is caused by the magnetic field generated as a result of the flowing of the main magnetic field generating current ±g(0)·IBLin the bit line BLn″when data are written into the tunnel magnetoresistance devices (tunnel magnetoresistance device TMJ(1,n″)−tunnel magnetoresistance device TMJ(M,n″)) electrically connected to the bit line BLn″[n″=n±2, and 3≦n″≦(N−2)] adjacent to the n-th-place bit line BLn.

That is, when the main magnetic field generating current ±g(0)·IBLis passed through the adjacent bit line BLn′, the first compensatory magnetic field generating current ±g(±1)·IBLis passed through the n-th-place bit line BLn. Further, when the main magnetic field generating current ±g(0)·IBLis passed through the adjacent bit line BLn″, the second compensatory magnetic field generating current ±g(±2)·IBLis passed through the n-th-place bit line BLn. When it is not required to write data into the tunnel magnetoresistance device TMJ, no current is passed through any bit line.

The write-in word line RWLmis connected to a write-in word line current source RSmthrough an open/close circuit SWRWLmconstituted of a MOS-type FET. When the open/close circuit SWRWLmis in an ON-state, the current IRWLflows in the write-in word line RWLm.

In the nonvolatile magnetic memory device in Example 1, when data is written into the tunnel magnetoresistance device TMJ, the open/close circuit SWRWL1is brought into an ON-state to pass (flow) the current IRWLthrough (in) the first write-in word line RWL1from the write-in word line current source RS1. And, the main magnetic field generating current ±g(0)·IBLis passed through (or flowed in) the first bit line BL1, the first compensatory magnetic field generating current ±g(±1)·IBLis passed through (or flowed in) the second bit line BL2, and the second compensatory magnetic field generating current ±g(±2)·IBLis passed through (or flowed in) the third bit line BL3. These procedures are consecutively repeated from the second write-in word line RWL2to the M-th-place write-in word line RWLM.

Then, again, the current IRWLis passed through (or flowed in) the first write-in word line RWL1from the write-in word line current source RS1. And, the main magnetic field generating current ±g(0)·IBLis passed through (or flowed in) the second bit line BL2, the first compensatory magnetic field generating currents ±g(±1)·IBLare passed through (or flowed in) the first bit line BL1and the third bit line BL3, and the second compensatory magnetic field generating current ±g(±2)·IBLis passed through (or flowed in) the fourth bit line BL4. These procedures are consecutively repeated from the second write-in word line RWL2to the M-th-place write-in word line RWLM.

Further, again, the current IRWLis passed through (or flowed in) the first write-in word line RWL1from the write-in word line current source RS1. And, the main magnetic field generating current ±g(0)·IBLis passed through (or flowed in) the third bit line BL3, the first compensatory magnetic field generating currents ±g(±1)·IBLare passed through (or flowed in) the second bit line BL2and the fourth bit line BL4, and the second compensatory magnetic field generating currents ±g(±2)·IBLare passed through (or flowed in) the first bit line BL1and the fifth bit line BL5. These procedures are consecutively repeated from the second write-in word line RWL2to the M-th-place write-in word line RWLM. Further, these procedures are consecutively repeated from the fourth bit line BL4to the (N−2)-th-place bit line BLN−2.

Then, again, the current IRWLis passed through (or flowed in) the first write-in word line RWL1from the write-in word line current source RS1. And, the main magnetic field generating current ±g(0)·IBLis passed through (or flowed in) the (N−1)-th-place bit line BLN−1, the first compensatory magnetic field generating currents ±g(±1)·IBLare passed through (or flowed in) the (N−2)-th-place bit line BLN−2and the N-th-place bit line BLN, and the second compensatory magnetic field generating current ±g(±2)·IBLis passed through (or flowed in) the (N−3)-th-place bit line BLN−3. These procedures are consecutively repeated from the second write-in word line RWL2to the M-th-place write-in word line RWLM.

Further, again, the current IRWLis passed through (or flowed in) the first write-in word line RWL1from the write-in word line current source RS1. And, the main magnetic field generating current ±g(0)·IBLis passed through (or flowed in) the N-th-place bit line BLN, the first compensatory magnetic field generating current ±g(±1)·IBLis passed through (or flowed in) the (N−1)-th-place bit line BLN−1, and the second compensatory magnetic field generating current ±g(±2)·IBLis passed through (or flowed in) the (N−2)-th-place bit line BLN−2. These procedures are consecutively repeated from the second write-in word line RWL2to the M-th-place write-in word line RWLM.

The above-explained operation is given as an example and may be modified as required. In Examples 2 to 5, further, data can be written into tunnel magnetoresistance devices that are M×N in number, substantially by the same method.

[Writing of Data into Tunnel Magnetoresistance Device TMJ(2,4)]

A case of writing data into the tunnel magnetoresistance device TMJ(2,4)connected to the fourth bit line BL4and positioned in the overlap region of the fourth bit line BL4and the second write-in word line RWL2(opposed to the second write-in word line RWL2) will be explained below as an example.

Immediately before data is written, all of the open/close circuits SWRWLm(m=1, 2, . . . M) are in an OFF-state. For starting the writing of data, the open/close circuit SWRWL2is brought into an ON-state, whereby the current IRWLis passed through (or flowed in) the second write-in word line RWL2from the write-in word line current source RS2. In the current source unit BCS4, the open/close circuit SWBLn−i(n=4, i=1 or 2) is selected and brought into an ON-state, depending upon which data, “1” or “0”, is written into the tunnel magnetoresistance device TMJ(2,4). As a result, the main magnetic field generating current g(0)·IBL(when data “1” is written) flows in the fourth bit line BL4, or the main magnetic field generating current −g(0)·IBL(when data “0” is written) flows in the fourth bit line BL4.

When data “1” is written in the tunnel magnetoresistance device TMJ(2,4), in the current source unit BCS3and the current source unit BCS5, the open/close circuits SWBLn−i(n=3 and 5, i=3) are selected to come into an ON-state. As a result, the first compensatory magnetic field generating currents g(±1)·IBLflow in the third bit line BL3and the fifth bit line BL5. On the other hand, when data “0” is written into the tunnel magnetoresistance device TMJ(2,4), in the current source unit BCS3and the current source unit BCS5, the open/close circuits SWBLn−i(n=3 and 5, i=4) are selected to come into an ON-state. As a result, the first compensatory magnetic field generating currents −g(±1)·IBLflow in the third bit line BL3and the fifth bit line BL5.

Further, when data “1” is written in the tunnel magnetoresistance device TMJ(2,4), in the current source unit BCS2and the current source unit BCS6, the open/close circuits SWBLn−i(n=2 and 6, i=5) are selected to come into an ON-state. As a result, the second compensatory magnetic field generating currents g(±2)·IBLflow in the second bit line BL2and the sixth bit line BL6. On the other hand, when data “0” is written in the tunnel magnetoresistance device TMJ(2,4), in the current source unit BCS2and the current source unit BCS6, the open/close circuits SWBLn−i(n=2 and 6, i=6) are selected to come into an ON-state. As a result, the second compensatory magnetic field generating currents −g(±2)·IBLflow in the second bit line BL2and the sixth bit line BL6.

By the synthetic field generated as the result of the above [synthetic magnetic field of (1) the magnetic field generated by the current IRWLflowing in the second write-in word line RWL2; (2) the magnetic field generated by the main magnetic field generating current g(0)·IBLflowing in the fourth bit line BL4; (3) the magnetic fields generated by the first compensatory magnetic field generating currents g(±1)·IBLflowing in the third and fifth bit lines BL3and BL5; and (4) the magnetic fields generated by the second compensatory magnetic field generating currents g(±2)·IBLflowing in the second and sixth bit lines BL2and BL6], the magnetization direction of the second ferromagnetic layer (memory layer)35in the tunnel magnetoresistance device TMJ(2,4)is changed, to record “1” in the second ferromagnetic layer (memory layer)35. Alternatively, by the synthetic magnetic field [synthetic magnetic field of (1) the magnetic field generated by the current IRWLflowing in the second write-in word line RWL2; (2) the magnetic field generated by the main magnetic field generating current −g(0)·IBLflowing in the fourth bit line BL4; (3) the magnetic fields generated by the first compensatory magnetic field generating currents−g(±1)·IBLflowing in the third and fifth bit lines BL3and BL5; and (4) the magnetic fields generated by the second compensatory magnetic field generating currents −g(±2)·IBLflowing in the second and sixth bit lines BL2and BL6], the magnetization direction of the second ferromagnetic layer (memory layer)35in the tunnel magnetoresistance device TMJ(2,4)is changed, to record “0” in the second ferromagnetic layer (memory layer)35. On the other hand, the magnetization direction of the second ferromagnetic layer (memory layer)35of each of the tunnel magnetoresistance devices TMJ(2,2), TMJ(2,3), TMJ(2,5)and TMJ(2,6)remains unchanged by the above synthetic magnetic field.

The values of the current IRWLand the current IBLare determined beforehand such that the synthetic magnetic field in the second ferromagnetic layer (memory layer)35of the tunnel magnetoresistance device TMJ(2,4)has a value included in the region (OUT1) in the asteroid curve shown inFIG. 38, and that the synthetic magnetic field in the second ferromagnetic layer (memory layer)35of each of the tunnel magnetoresistance devices TMJ(2,2), TMJ(2,3), TMJ(2,5)and TMJ(2,6)has a value included in the region (IN) in the asteroid curve shown inFIG. 38. The above is also applicable to Examples hereinafter.

There may be employed a constitution in which the magnetic field (HEA) in the easy-magnetization axis direction of the memory layer35is generated by the current flowing in the bit line, and the magnetic field (HHA) in the hard-magnetization direction of the memory layer35is generated by the current IRWLflowing in the write-in word line, or there may be employed a constitution in which the magnetic field (HHA) in the hard-magnetization direction of the memory layer35is generated by the current flowing in the bit line, and the magnetic field (HEA) in the easy-magnetization axis direction of the memory layer35is generated by the current IRWLflowing in the write-in word line. The above is also applicable to Examples 2 to 5 to be described later.

[Writing of Data into Tunnel Magnetoresistance Device TMJ(m,n)]

Generally, when data is written into the tunnel magnetoresistance device TMJ(m,n)connected to the n-th-place bit line BLn[n=3, 4, . . . (N−3), (N−2)] and positioned in the overlap region of the n-th-place bit line BLnand the m-th-place write-in word line RWLm(opposed to the m-th-place write-in word line RWLm), the following operation is carried out.

Immediately before data is written, all of the open/close circuits SWRWLm(m=1, 2, . . . M) are in an OFF-state. For starting the writing of data, the open/close circuit SWRWLmis brought into an ON-state, whereby the current IRWLis passed through (or flowed in) the m-th-place write-in word line RWLmfrom the write-in word line current source RSm. In the current source unit BCSn, the open/close circuit SWBLn−i(i=1 or 2) is selected to come into an ON-state, depending upon which data, “1” or “0”, is written into the tunnel magnetoresistance device TMJ(m,n). As a result, the main magnetic field generating current g(0)·IBL(when data “1” is written) flows in the n-th-place bit line BLn, or the main magnetic field generating current −g(0)·IBL(when data “0” is written) flows in the n-th-place bit line BLn.

When data “1” is written into the tunnel magnetoresistance device TMJ(m,n), in the current source unit BCSn−1and the current source unit BCSn+1, the open/close circuits SWBLn′−i[n′=(n−1) and (n+1), i=3] are selected to come into an ON-state. As a result, the first compensatory magnetic field generating currents g(±1)·IBLflow in the (n−1)-th-place bit line BLn−1and the (n+1)-th-place bit line BLn+1. When data “0” is written in the tunnel magnetoresistance device TMJ(m,n), in the current source unit BCSn−1and the current source unit BCSn+1, the open/close circuits SWBLn′−i[n′=(n+1) and (n−1), i=4] are selected to come into an ON-state. As a result, the first compensatory magnetic field generating currents−g(±1)·IBLflow in the (n−1)-th-place bit line BLn−1and the (n+1)-th-place bit line BLn+1.

Further, when data “1” is written into the tunnel magnetoresistance device TMJ(m,n), in the current source unit BCSn−2and the current source unit BCSn+2, the open/close circuits SWBLn″−i[n″=(n−2) and (n+2), i=5] are selected to come into an ON-state. As a result, the second compensatory magnetic field generating currents g(±2)·IBLflow in the (n−2)-th-place bit line BLn−2and the (n+2)-th-place bit line BLn+2. When data “0” is written into the tunnel magnetoresistance device TMJ(m,n), in the current source unit BCSn−2and the current source unit BCSn+2, the open/close circuits SWBLn″−i[n=(n−2) and (n+2), i=6] are selected to come into an ON-state. As a result, the second compensatory magnetic field generating currents −g(±2)·IBLflow in the (n−2)-th-place bit line BLn−2and the (n+2)-th-place bit line BLn+2.

[Writing of Data into Tunnel Magnetoresistance Device TMJ(m,1)or TMJ(m,N)]

When data is written into the tunnel magnetoresistance device TMJ(m,Q)connected to the Q-th-place bit line BLQ[Q=1 or N] and positioned in the overlap region of the Q-th-place bit line and the m-th-place write-in word line RWLm(opposed to the m-th-place write-in word line RWLm), the following operation is carried out.

Immediately before data is written, all of the open/close circuits SWRWLm(m=1, 2, . . . M) are in an OFF-state. For starting the writing of data, the open/close circuit SWRWLmis brought into an ON-state, whereby the current IRWLis passed through (or flowed in) the m-th-place write-in word line RWLmfrom the write-in word line current source RSm. In the current source unit BCSQ, the open/close circuit SWBLQ−i(i=1 or 2) is selected to come into an ON-state, depending upon which data, “1” or “0”, is written into the tunnel magnetoresistance device TMJ(m,Q). As a result, the main magnetic field generating current g(0)·IBL(when data “1” is written) flows in the Q-th-place bit line BLQ, or the main magnetic field generating current −g(0)·IBL(when data “0” is written) flows in the Q-th-place bit line BLQ.

When data “1” is written into the tunnel magnetoresistance device TMJ(m,Q), in the current source unit BCS2or the current source unit BCSN−1the open/close circuit SWBLQ′−i[Q′=2 or (N−1), i=3] is selected to come into an ON-state. As a result, the first compensatory magnetic field generating current g(±1)·IBLflows in the second bit line BL2or the (N−1)-th-place bit line BLN−1. When data “0” is written in the tunnel magnetoresistance device TMJ(m,Q), in the current source unit BCS2or the current source unit BCSN−1, the open/close circuit SWBLQ′−i[Q′=2 or (N−1), i=4] is selected to come into an ON-state. As a result, the first compensatory magnetic field generating current −g(±1)·IBLflows in the second bit line BL2or the (N−1)-th-place bit line BLN−1.

Further, when data “1” is written into the tunnel magnetoresistance device TMJ(m,Q), in the current source unit BCS3or the current source unit BCSN−2, the open/close circuit SWBLQ″−i[Q″=3 or (N−2), i=5] is selected to come into an ON-state. As a result, the second compensatory magnetic field generating current g(±2)·IBLflows in the third bit line BL3or the (N−2)-th-place bit line BLN−2. When data “0” is written into the tunnel magnetoresistance device TMJ(m,Q), in the current source unit BCS3or the current source unit BCSN−2, the open/close circuit SWBLQ″−i[Q″=3 or (N−2), i=6] is selected to come into an ON-state. As a result, the second compensatory magnetic field generating current −g(±2)·IBLflows in the third bit line BL3or the (N−2)-th-place bit line BLN−2.

[Writing of Data into Tunnel Magnetoresistance Device TMJ(m,2)or TMJ(m,N−1)]

When data is written into the tunnel magnetoresistance device TMJ(m,Q)connected to the Q-th-place bit line BLQ[Q=2 or (N−1)] and positioned in the overlap region of the Q-th-place bit line BLQand the m-th-place write-in word line RWLm(opposed to the m-th-place write-in word line RWLm), the following operation is carried out.

Immediately before data is written, all of the open/close circuits SWRWLm(m=1, 2, . . . M) are in an OFF-state. For starting the writing of data, the open/close circuit SWRWLmis brought into an ON-state, whereby the current IRWLis passed through (or flowed in) the m-th-place write-in word line RWLmfrom the write-in word line current source RSm. In the current source unit BCSQ, the open/close circuit SWBLQ−i(i=1 or 2) is selected to come into an ON-state, depending upon which data, “1” or “0”, is written into tunnel magnetoresistance device TMJ(m,Q). As a result, the main magnetic field generating current g(0)·IBL(when data “1” is written) flows in the Q-th-place bit line BLQ, or the main magnetic field generating current −g(0)·IBL(when data “0” is written) flows in the Q-th-place bit line BLQ.

When data “1” is written into the tunnel magnetoresistance device TMJ(m,Q), in the current source unit BCS1and the current source unit BCS3, or in the current source unit BCSN−2and the current source unit BCSN, the open/close circuits SWBLQ′−i[Q′=1 and 3, or Q′=(N−2) and N, i=3] are selected to come into an ON-state. As a result, the first compensatory magnetic field generating currents g(±1)·IBLflow in the first bit line BL1and the third bit line BL3, or in the (n−2)-th-place bit line BLN−2and the N-th-place bit line BLn. When data “0” is written in the tunnel magnetoresistance device TMJ(m,Q), in the current source unit BCS1and the current source unit BCS3, or in the current source unit BCSN−2and the current source unit BCSN, the open/close circuits SWBLQ′−i[Q′=1 and 3, or Q′=(N−2) and N, i=4] are selected to come into an ON-state. As a result, the first compensatory magnetic field generating currents −g(±1)·IBLflow in the first bit line BL1and the third bit line BL3, or in the (N−2)-th-place bit line BLN−2and the N-th-place bit line BLN.

Further, when data “1” is written into the tunnel magnetoresistance device TMJ(m,Q), in the current source unit BCS4or the current source unit BCSN−3, the open/close circuit SWBLQ″−i[Q″=4 or (N−3), i=5] is selected to come into an ON-state. As a result, the second compensatory magnetic field generating current g(±2)·IBLflows in the fourth bit line BL4or the (N−3)-th-place bit line BLN−3. When data “0” is written into the tunnel magnetoresistance device TMJ(m,Q), in the current source unit BCS4or the current source unit BCSN−3, the open/close circuit SWBLQ″−i[Q″=4 or (N−3), i=6] is selected to come into an ON-state. As a result, the second compensatory magnetic field generating current −g(±2)·IBLflows in the fourth bit line BL4or the (N−3)-th-place bit line BLN−3.

In the nonvolatile magnetic memory device in Example 1, when data is written into the tunnel magnetoresistance device TMJ(m,n), the main magnetic field generating current ±g(0)·IBLis passed through (or flowed in) the bit line BLnfrom the current source unit BCSn, and the compensatory magnetic field generating currents ±g(±1)·IBLand ±g(±2)·IBLare passed through (or flowed in) the bit lines BLn−1, BLn+1, BLn−2and BLn+2from the current source units BCSn−1, BCSn+1, BCSn−2and BCSn+2. As a result, the destruction of data stored in the tunnel magnetoresistance devices TMJ(m,n−2), TMJ(m,n−1), TMJ(m,n+1)and TMJ(m,n+2)electrically connected to the bit lines BLn−2, BLn−1, BLn+1and BLn+2can be reliably prevented.

Example 2 is a variant of Example 1.FIG. 8shows an equivalent circuit diagram of a nonvolatile magnetic memory device in Example 2.

In the nonvolatile magnetic memory device explained in Example 1, for example, the main magnetic field is generated by the current flowing in the first bit line BL1or the N-th-place bit line BLN[magnetic field generated by the current g(0)·I(1)BLor current g(0)·I(N)BL], and the compensatory magnetic fields are generated by the currents flowing in the second and third bit lines BL2and BL3or the currents flowing in the (N−2)-th-place and (N−1)-th-place bit lines BL(N−2)and BL(N−1)[magnetic fields generated by the current g(1)·I(1)BLand the current g(2)·I(1)BL, or by the current g(−2)·I(N)BLand the current g(−1)·I(N)BL], while these compensatory magnetic fields become asymmetric, for example, with regard to the first bit line BL1or the N-th-place bit line BLN.

In the nonvolatile magnetic memory device in Example 2, therefore, when the absolute value of the maximum value that k represents is k0(k0=2 in Example 2),

a group of first dummy lines that are k0in number (first dummy lines DL11and DL12) is provided outside the first bit line BL1and in parallel with the first bit line BL1,

a group of second dummy lines that are k0in number (second dummy lines DL21and DL22) is provided outside the N-th-place bit line BLNand in parallel with the N-th-place bit line BLN, and

a current g(k)·I(n)BLis passed through (or flowed in) the [(1−n)+|k|]-th-place first dummy line constituting the group of the first dummy lines or the [n−N+|k|]-th-place second dummy line constituting the group of the second dummy lines.

Specifically, when the main magnetic field generating current ±g(0)·IBLis passed through (or flowed in) the first bit line BL1, the first compensatory magnetic field generating current ±g(−1)·I(n)BLis passed through (or flowed in) the [(1−n)+|k|]-th-place first dummy line DL11(n=1, k=−1, first-place first dummy line) constituting the group of the first dummy lines, and the second compensatory magnetic field generating current ±g(−2)·I(n)BLis passed through (or flowed in) the [(1−n)+|k|]-th-place first dummy line DL12(n=1, k=−2, and second-place first dummy line) constituting the group of the first dummy lines. Further, when the main magnetic field generating current ±g(0)·IBLis passed through (or flowed in) the second bit line BL2, the second compensatory magnetic field generating current ±g(−2)·I(n)BLis passed through (or flowed in) the [(1−n)+|k|]-th-place first dummy line DL11(n=2, k=−2, first-place first dummy line) constituting the group of the first dummy lines.

On the other hand, when the main magnetic field generating current ±g(0)·IBLis passed through (or flowed in) the N-th-place bit line BLN, the first compensatory magnetic field generating current ±g(1)·I(n)BLis passed through (or flowed in) the [n−N+|k|]-th-place second dummy line DL21(n=N, k=1, first-place second dummy line) constituting the group of the second dummy lines, and the second compensatory magnetic field generating current ±g(−2)·I(n)BLis passed through (or flowed in) the [n−N+|k|]-th-place second dummy line DL22(n=N, k=2, and second-place second dummy line) constituting the group of the second dummy lines. Further, when the main magnetic field generating current ±g(0)·IBLis passed through (or flowed in) the (N−1)-th-place bit line BLN−1, the second compensatory magnetic field generating current ±g(2)·I(n)BLis passed through (or flowed in) the [n−N+|k|]-th-place second dummy line DL21(n=N−1, k=2, first-place second dummy line) constituting the group of the second dummy lines.

The first-place first dummy line DL11constituting the group of the first dummy lines is connected to a first dummy line current source DLCS11(see an equivalent circuit diagram ofFIG. 9A), the second-place first dummy line DL12constituting the group of the first dummy lines is connected to a first dummy line current source DLCS12(see an equivalent circuit diagram ofFIG. 9B), the first-place second dummy line DL21constituting the group of the second dummy lines is connected to a second dummy line current source DLCS21(see an equivalent circuit diagram ofFIG. 10A), and the second-place second dummy line DL22constituting the group of the second dummy lines is connected to a second dummy line current source DLCS22(see an equivalent circuit diagram ofFIG. 10B).

The first dummy line current source DLCS11is provided with open/close circuits SWDL-11−i(i=1, 2, 3, 4) constituted of a MOS-type FET each, and by the ON/OFF operation of the open/close circuit SWDL-11−i, one of four currents, the current g(−1)·IBL, the current −g(−1)·IBL, the current g(−2)·IBLand the current −g(−2)·IBL, can be passed through (or flowed in) the first-place first dummy line DL11constituting the group of the first dummy lines from the first dummy line current source DLCS11. The second dummy line current source DLCS21is provided with open/close circuits SWDL-21−i(i=1, 2, 3, 4) constituted of a MOS-type FET each, and by the ON/OFF operation of the open/close circuit SWDL-21−i, one of four currents, the current g(1)·IBL, the current −g(1)·IBL, the current g(2)·IBLand the current −g(2)·IBL, can be passed through (or flowed in) the first-place second dummy line DL21constituting the group of the second dummy lines from the second dummy line current source DLCS21.

Further, the first dummy line current source DLCS12is provided with open/close circuits SWDL-12−i(i=1, 2) constituted of a MOS-type FET each, and by the ON/OFF operation of the open/close circuit SWDL-12−i, one of two currents, the current g(−2)·IBLand the current −g(−2)·IBL, can be passed through (or flowed in) the second-place first dummy line DL12constituting the group of the first dummy lines from the first dummy line current source DLCS12. The second dummy line current source DLCS22is provided with open/close circuits SWDL-22−i(i=1, 2) constituted of a MOS-type FET each, and by the ON/OFF operation of the open/close circuit SWDL-22−i, one of two currents, the current g(2)·IBLand the current −g(2)·IBL, can be passed through (or flowed in) the second-place second dummy line DL22constituting the group of the second dummy lines from the second dummy line current source DLCS22.

The constitution, structure and operation of the nonvolatile magnetic memory device in Example 2 can be the same as those of the nonvolatile magnetic memory device in Example 1 except for the above points, so that a detailed explanation thereof will be omitted. The values of the coefficients g(1), g(−1), g(2) and g(−2) can be determined so as to be the same as those in Example 1.

In the nonvolatile magnetic memory device in Example 2, the compensatory magnetic field for preventing the destruction of data stored in the tunnel magnetoresistance device becomes symmetric with regard to the first bit line BL1, the second bit line BL2, the (N−1)-th-place bit line BLN−1and the N-th-place bit line BLN, so that the operation of writing data into the nonvolatile magnetic memory device is more stabilized.

Example 3 is also a variant of Example 1.FIG. 11shows an equivalent circuit diagram of a nonvolatile magnetic memory device in Example 3.FIG. 12shows an equivalent circuit diagram of a first current source unit41and a first switch circuit41A in the nonvolatile magnetic memory device in Example 3.FIG. 13shows an equivalent circuit diagram of a second current source unit42and a second switch circuit42A.FIG. 14shows an equivalent circuit diagram of a third current source unit43and a third switch circuit43A.FIG. 15shows an equivalent circuit diagram of a fourth current source unit44and a fourth switch circuit44A.FIG. 16shows an equivalent circuit diagram of a fifth current source unit45and a fifth switch circuit45A.

In Example 3, the current source does not comprise the current source units that are N in number, but comprises the first current source unit41, the second current source unit42, the third current source unit43, the fourth current source unit44and the fifth current source unit45. The first current source unit41for letting the main magnetic field generating current ±g(0)·IBLflow on the bit lines BLnis connected to the bit lines BLn, that are N in number, through the first switch circuit41A (comprising open/close circuits SW SWMBL-1−SWMBL-8constituted of a MOS-type FET each). The second current source unit42for letting the first compensatory magnetic field generating current ±g(±1)·IBLflow in the bit lines BLnis connected to the bit lines BLn, that are N in number, through the second switch circuit42A (comprising open/close circuits SW SWCBL2-1–SWCBL2-8constituted of a MOS-type FET each). Further, the third current source unit43for letting the first compensatory magnetic field generating current ±g(±1)·IBLflow in the bit lines BLnis connected to the bit lines BLn, that are N in number, through the third switch circuit43A (comprising open/close circuits SW SWCBL3-1–SWCBL3-8constituted of a MOS-type FET each). The fourth current source unit44for letting the second compensatory magnetic field generating current ±g(±2)·IBLflow in the bit lines BLnis connected to the bit lines BLn, that are N in number, through the fourth switch circuit44A (comprising open/close circuits SW SWCBL4-1–SWCBL4-8constituted of a MOS-type FET each). Further, the fifth current source unit45for letting the second compensatory magnetic field generating current ±g(±2)·IBLflow in the bit lines BLnis connected to the bit lines BLn, that are N in number, through the fifth switch circuit45A (comprising open/close circuits SW SWCBL5-1–SWCBL5-8constituted of a MOS-type FET each).

The constitution, structure and operation of the nonvolatile magnetic memory device in Example 3 can be the same as those of the nonvolatile magnetic memory device in Example 1 except for the above points, so that a detailed explanation thereof will be omitted. In Example 3, the above constitution is employed, so that the number of the current source units can be decreased, and that the constitution of the nonvolatile magnetic memory device can be simplified.

[Writing of Data into Tunnel Magnetoresistance Device TMJ(m,n)]

When data is written into the tunnel magnetoresistance device TMJ(m,n)connected to the n-th-place bit line BLn[n=3, 4, . . . (N−2)] and positioned in the overlap region of the n-th-place bit line BLnand the m-th-place write-in word line RWLm(opposed to the m-th-place write-in word line RWLm), the following operation is carried out.

Immediately before data is written, all of the open/close circuits SWRWLm(m=1, 2, . . . M) are in an OFF-state. For starting the writing of data, the open/close circuit SWRWLmis brought into an ON-state, whereby the current IRWLis passed through (or flowed in) the m-th-place write-in word line RWLmfrom the write-in word line current source RSm. In the first current source unit41, the open/close circuit SWM−i(i=1 or 2) constituted of a MOS-type FET is selected to come into an ON-state, depending upon which data, “1” or “0”, is written into the tunnel magnetoresistance device TMJ(m,n). Further, the open/close circuit SWMBL-nconstituting the first switch circuit41A is selected to come into an ON-state. As a result, the main magnetic field generating current g(0)·IBLor −g(0)·IBLflows in the n-th-place bit line BLn.

When data “1” is written into the tunnel magnetoresistance device TMJ(m,n), in the second current source unit42and the third current source unit43, the open/close circuit SWC2-1and the open/close circuit SWC3-1are selected to come into an ON-state. Further, the open/close circuit SWCBL2-(n−1)constituting the second switch circuit42A is selected to come into an ON-state, and the open/close circuit SWCBL3-(n+1)constituting the third switch circuit43A is selected to come into an ON-state. As a result, the first compensatory magnetic field generating currents g(±1)·IBLflow in the (n−1)-th-place bit line BLn−1and the (n+1)-th-place bit line BLn+1. Further, in the fourth current source unit44and the fifth current source unit45, the open/close circuit SWC4-1and the open/close circuit SWC5-1are selected to come into an ON-state. Further, the open/close circuit SWCBL4-(n−2)constituting the fourth switch circuit44A is selected to come into an ON-state, and the open/close circuit SWCBL5-(n+2)constituting the fifth switch circuit45A is selected to come into an ON-state. As a result, the second compensatory magnetic field generating currents g(±2)·IBLflow in the (n−2)-th-place bit line BLn−2and the (n+2)-th-place bit line BLn+2.

When data “0” is written in the tunnel magnetoresistance device TMJ(m,n), in the second current source unit42and the third current source unit43, the open/close circuit SWC2-2and the open/close circuit SWC3-2are selected to come into an ON-state. Further, the open/close circuit SWCBL2-(n−1)constituting the second switch circuit42A is selected to come into an ON-state, and the open/close circuit SWCBL3-(n+1)constituting the third switch circuit43A is selected to come into an ON-state. As a result, the first compensatory magnetic field generating currents −g(±1)·IBLflow in the (n−1)-th-place bit line BLn−1and the (n+1)-th-place bit line BLn+1. Further, in the fourth current source unit44and the fifth current source unit45, the open/close circuit SWC4-2and the open/close circuit SWC5-2are selected to come into an ON-state. Further, the open/close circuit SWCBL4-(n−2)constituting the fourth switch circuit44A is selected to come into an ON-state, and the open/close circuit SWCBL5-(n+2)constituting the fifth switch circuit45A is selected to come into an ON-state. As a result, the second compensatory magnetic field generating currents −g(±2)·IBLflow in the (n−2)-th-place bit line BLn−2and the (n+2)-th-place bit line BLn+2.

By the synthetic magnetic field generated as the result of the above [synthetic magnetic field of (1) the magnetic field generated by the current flowing in the m-th-place write-in word line RWLm; (2) the magnetic field generated by the main magnetic field generating current g(0)·IBLflowing in the n-th-place bit line BLn; (3) the magnetic fields generated by the first compensatory magnetic field generating currents g(±1)·IBLflowing in the (n−1)-th-place and (n+1)-th-place bit lines BLn−1and BLn+1; and (4) the magnetic fields generated by the second compensatory magnetic field generating currents g(±2)·IBLflowing in the (n−2)-th-place and (n+2)-th-place bit lines BLn−2and BLn+1], the magnetization direction of the second ferromagnetic layer (memory layer)35in the tunnel magnetoresistance device TMJ(m,n)is changed, to record “1” in the second ferromagnetic layer (memory layer)35. Alternatively, by the synthetic magnetic field [the synthetic magnetic field of (1) the magnetic field generated by the current IRWLflowing in the m-th-place write-in word line RWLm; (2) the magnetic field generated by the main magnetic field generating current −g(0)·IBLflowing in the n-th-place bit line BLn; (3) the magnetic fields generated by the first compensatory magnetic field generating currents −g(±1)·IBLflowing in the (n−1)-th-place and (n+1)-th-place bit lines BLn−1and BLn+1; and (4) the magnetic fields generated by the second compensatory magnetic field generating currents −g(±2)·IBLflowing in the (n−2)-th-place and (n+2)-th-place bit lines BLn−2and BLn+2], the magnetization direction of the second ferromagnetic layer (memory layer)35in the tunnel magnetoresistance device TMJ(m,n)is changed, to record “0” in the second ferromagnetic layer (memory layer)35. On the other hand, the magnetization direction of the second ferromagnetic layer (memory layer)35of each of the tunnel magnetoresistance devices TMJ(m,n−2), TMJ(m,n−1), TMJ(m,n+1)and TMJ(m,n+2)remains unchanged by the above synthetic magnetic field.

[Writing of Data into Tunnel Magnetoresistance Device TMJ(m,1)or TMJ(m,N)]

When data is written into the tunnel magnetoresistance device TMJ(m,Q)connected to the Q-th-place bit line BLQ[Q=1 or N] and positioned in the overlap region of the Q-th-place bit line BLQand the m-th-place write-in word line RWLm(opposed to the m-th-place write-in word line RWLm), the following operation is carried out.

Immediately before data is written, all of the open/close circuits SWRWLm(m=1, 2, . . . M) are in an OFF-state. For starting the writing of data, the open/close circuit SWRWLmis brought into an ON-state, whereby the current IRWLis passed through (or flowed in) the m-th-place write-in word line RWLmfrom the write-in word line current source RSm. In the first current source unit41, the open/close circuit SWM−1(i=1 or 2) constituted of a MOS-type FET is selected to come into an ON-state, depending upon which data, “1” or “0”, is written into the tunnel magnetoresistance device TMJ(m,Q). Further, the open/close circuit SWMBL-Qconstituting the first switch circuit41A is selected to come into an ON-state, whereby the main magnetic field generating current ±g(0)·IBLflows in the Q-th-place bit line BLQ.

When data “1” is written into the tunnel magnetoresistance device TMJ(m,Q), in the second current source unit42or the third current source unit43, the open/close circuit SWC2-1or the open/close circuit SWC3-1is selected to come into an ON-state. Further, the open/close circuit SWCBL2-(N−1)constituting the second switch circuit42A is selected to come into an ON-state, or the open/close circuit SWCBL3-2constituting the third switch circuit43A is selected to come into an ON-state, whereby the first compensatory magnetic field generating current g(±1)·IBLflows in the second bit line BL2or the (N−1)-th-place bit line BLN−1. Further, in the fourth current source unit44or the fifth current source unit45, the open/close circuit SWC4-1or the open/close circuit SWC5-1is selected to come into an ON-state. Further, the open/close circuit SWCBL4-(N−2)constituting the fourth switch circuit44A is selected to come into an ON-state, or the open/close circuit SWCBL5-3constituting the fifth switch circuit45A is selected to come into an ON-state. As a result, the second compensatory magnetic field generating current g(±2)·IBLflows in the third bit line BL3or the (N−2)-th-place bit line BLN−2.

When data “0” is written in the tunnel magnetoresistance device TMJ(m,n), in the second current source unit42or the third current source unit43, the open/close circuit SWC2-2or the open/close circuit SWC3-2is selected to come into an ON-state. Further, the open/close circuit SWCBL2-(N−1)constituting the second switch circuit42A is selected to come into an ON-state, or the open/close circuit SWCBL3-2constituting the third switch circuit43A is selected to come into an ON-state. As a result, the first compensatory magnetic field generating current −g(±1)·IBLflows in the second bit line BL2or the (N−1)-th-place bit line BLN−1. Further, in the fourth current source unit44or the fifth current source unit45, the open/close circuit SWC4-2or the open/close circuit SWC5-2is selected to come into an ON-state. Further, the open/close circuit SWCBL4-(N−2)constituting the fourth switch circuit44A is selected to come into an ON-state, or the open/close circuit SWCBL5-3constituting the fifth switch circuit45A is selected to come into an ON-state. As a result, the second compensatory magnetic field generating current −g(±2)·IBLflows in the third bit line BL3, or the (N−2)-th-place bit line BLN−2.

[Writing of Data into Tunnel Magnetoresistance Device TMJ(m,2)or TMJ(m,N−1)]

When data is written into the tunnel magnetoresistance device TMJ(m,Q)connected to the Q-th-place bit line BLQ[Q=2 or (N−1)] and positioned in the overlap region of the Q-th-place bit line BLQand the m-th-place write-in word line RWLm(opposed to the m-th-place write-in word line RWLm), the following operation is carried out.

Immediately before data is written, all of the open/close circuits SWRWLm(m=1, 2, . . . M) are in an OFF-state. For starting the writing of data, the open/close circuit SWRWLmis brought into an ON-state, whereby the current IRWLis passed through (or flowed in) the m-th-place write-in word line RWLmfrom the write-in word line current source RSm. In the first current source unit41, the open/close circuit SWM−i(i=1 or 2) constituted of a MOS-type FET is selected to come into an ON-state, depending upon which data, “1” or “0”, is written into the tunnel magnetoresistance device TMJ(m,Q). Further, the open/close circuit SWMBL-Qconstituting the first switch circuit41A is selected to come into an ON-state. As a result, the main magnetic field generating current ±g(0)·IBLflows in the Q-th-place bit line BLQ.

When data “1” is written into the tunnel magnetoresistance device TMJ(m,Q), in the second current source unit42and the third current source unit43, the open/close circuit SWC2-1and the open/close circuit SWC3-1are selected to come into an ON-state. Further, the open/close circuit SWCBL2-(Q−1)constituting the second switch circuit42A and the open/close circuit SWCBL3-(Q+1)constituting the third switch circuit43A are selected to come into an ON-state, whereby the first compensatory magnetic field generating currents g(±1)·IBLflow in the first bit line BL1and the third bit line BL3or in the (N−2)-th-place bit line BLN−2and the N-th-place bit line BLN. Further, in the fourth current source unit44or the fifth current source unit45, the open/close circuit SWC4-1or the open/close circuit SWC5-1is selected to come into an ON-state. Further, the open/close circuit SWCBL4-(N−3)constituting the fourth switch circuit44A or the open/close circuit SWCBL5-4constituting the fifth switch circuit45A is selected to come into an ON-state. As a result, the second compensatory magnetic field generating current g(±2)·IBLflows in the fourth bit line BL4or the (N−3)-th-place bit line BLN−3.

When data “0” is written into the tunnel magnetoresistance device TMJ(m,Q), in the second current source unit42and the third current source unit43, the open/close circuit SWC2-2and the open/close circuit SWC3-2are selected to come into an ON-state. Further, the open/close circuit SWCBL2-(Q−1)constituting the second switch circuit42A and the open/close circuit SWCBL3-(Q+1)constituting the third switch circuit43A are selected to come into an ON-state. As a result, the first compensatory magnetic field generating currents −g(±1)·IBLflow in the first bit line BL1and the third bit line BL3, or in the (N−2)-th-place bit line BLN−2and the N-th-place bit line BLN. Further, in the fourth current source unit44or the fifth current source unit45, the open/close circuit SWC4-2or the open/close circuit SWC5-2is selected to come into an ON-state. Further, the open/close circuit SWCBL4-(N−3)constituting the fourth switch circuit44A is selected to come into an ON-state, or the open/close circuit SWCBL5-4constituting the fifth switch circuit45A is selected to come into an ON-state. As a result, the second compensatory magnetic field generating current −g(±2)·IBLflows in the fourth bit line BL4or the (N−3)-th-place bit line BLN−3.

In the nonvolatile magnetic memory device in Example 3, when data is written into the tunnel magnetoresistance device TMJ(m,n), the main magnetic field generating current ±g(0)·IBLis passed through (or flowed in) the bit line BLnfrom the first current source unit41, and the compensatory magnetic field generating currents ±g(±2)·IBL, ±g(±1)·IBL, ±g(±1)·IBLand ±g(+2)·IBLare passed through (or flowed in) the bit lines BLn−2, BLn−1, BLn+1and BLn+2from the fourth current source unit44, the second current source unit42, the third current source unit43and the fifth current source unit45. As a result, the destruction of data stored in the tunnel magnetoresistance devices TMJ(m,n−2), TMJ(m,n−1), TMJ(m,n+1)and TMJ(m,n+2)electrically connected to the bit lines BLn−2, BLn−1, BLn+1and BLn+2can be reliably prevented as well.

Example 4 is a variant of Example 3.FIG. 17shows an equivalent circuit diagram of a nonvolatile magnetic memory in Example 4.

In the nonvolatile magnetic memory device explained in Example 3, for example, the main magnetic field is generated by the current flowing in the first bit line BL1or the N-th-place bit line BLN[magnetic field generated by the current g(0)·IBLor the current g(0)·I(N)BL], and the compensatory magnetic fields are generated by the currents flowing in the second and third bit lines BL2and BL3or in the (N−2)-th-place and (N−1)-th-place bit lines BL(N−2)and BL(N−1)[magnetic fields generated by the current g(1)·I(1)BLand the current g(2)·I(1)BLor by the current g(−2)·I(N)BLand the current g(−1)·I(N)BL]. The above compensatory magnetic fields are asymmetric, for example, with regard to the first bit line BL1or the N-th-place bit line BLNas a base.

In the nonvolatile magnetic memory device in Example 4, therefore, when the absolute value of the maximum value that k represents is k0like Example 2 (k0=2 in Example 4),

a group of first dummy lines that are k0in number (first dummy lines DL11and DL12) is provided outside the first bit line BL1and in parallel with the first bit line BL1,

a group of second dummy lines that are k0in number (second dummy lines DL21and DL22) is provided outside the N-th-place bit line BLNand in parallel with the N-th-place bit line BLN, and

a current g(k)·I(n)BLis passed through (or flowed in) the [(1−n)+|k|]-th-place first dummy line constituting the group of the first dummy lines or passed through (or flowed in) the [n−N+|k|]-th-place second dummy line constituting the group of the second dummy lines.

Specifically, like Example 2, when the main magnetic field generating current ±g(0)·IBLis passed through (or flowed in) the first bit line BL1, the first compensatory magnetic field generating current ±g(±1)·I(n)BLis passed through (or flowed in) the [(1−n)+|k|]-th-place first dummy line DL11(n=1, k=−1, first-place first dummy line) constituting the group of the first dummy lines, and the second compensatory magnetic field generating currents ±g(±2)·I(n)BLis passed through (or flowed in) the [(1−n)+|k|]-th-place first dummy line DL12(n=1, k=−2, and second-place first dummy line) constituting the group of the first dummy lines. Further, when the main magnetic field generating current ±g(0)·IBLis passed through (or flowed in) the second bit line BL2, the second compensatory magnetic field generating current ±g(±2)·I(n)BLis passed through (or flowed in) the [(1−n)+|k|]-th-place first dummy line DL11(n=2, k=−2, first-place first dummy line) constituting the group of the first dummy lines.

When the main magnetic field generating current ±g(0)·IBLis passed through (or flowed in) the N-th-place bit line BLN, the first compensatory magnetic field generating current ±g(±1)·I(n)BLis passed through (or flowed in) the [n−N+|k|]-th-place second dummy line DL21(n=N, k=1, first-place second dummy line) constituting the group of the second dummy lines, and the second compensatory magnetic field generating current ±g(±2)·I(n)BLis passed through (or flowed in) the [n−N+|k|]-th-place second dummy line DL22(n=N, k=2, and second-place second dummy line) constituting the group of the second dummy lines. Further, when the main magnetic field generating current ±g(0)·IBLis passed through (or flowed in) the (N−1)-th-place bit line BLN−1, the second compensatory magnetic field generating current ±g(±2)·I(n)BLis passed through (or flowed in) the [n−N+|k|]-th-place second dummy line DL21(n=N−1, k=2, first-place second dummy line) constituting the group of the second dummy lines.

The first-place first dummy line DL11constituting the group of the first dummy lines is connected to the third current source unit43through an open/close circuit that is not shown, and further, is connected to the fifth current source unit45through an open/close circuit that is not shown. Further, the first-place second dummy line DL21constituting the group of the second dummy lines is connected to the second current source unit42through an open/close circuit that is not shown, and further, is connected to the fourth current source unit44through an open/close circuit that is not shown. The second-place first dummy line DL12constituting the group of the first dummy lines is connected to the fifth current source unit45through an open/close circuit that is not shown. The second-place second dummy line DL22constituting the group of the second dummy lines is connected to the fourth current source unit44through an open/close circuit that is not shown.

The constitution, structure and operation of the nonvolatile magnetic memory device in Example 4 can be the same as those of the nonvolatile magnetic memory device in Example 3 except for the above points, so that a detailed explanation thereof is omitted. The operation of the dummy lines can be substantially the same as that explained in Example 2, so that a detailed explanation thereof is omitted.

Example 5 is concerned with the method for writing data into a tunnel magnetoresistance device in a nonvolatile magnetic memory device (more specifically, a nonvolatile magnetic memory device having TMR-type MRAM) according to the first aspect of the present invention.

The nonvolatile magnetic memory device in Example 5 has the constitution and the structure that are explained in Example 2. While each bit line BLnis provided with a current source unit BCSnlike Example 2, a circuit (not shown) for adding the current g(0)·IBL, the current −g(0)·IBL, the current g(±1)·IBL, the current −g(±1)·IBL, the current g(±2)·IBLand the current −g(±2)·IBLis provided between the current source unit BCSnand the bit line BLn. Further, similarly, circuits (not shown) for adding the currents are provided between the first dummy line current source DLCS11and the first-place first dummy line DL11and between the second dummy line current source DLCS21and the first-place second dummy line DL21.

In Example 5, the current I(m)RWLis passed through (or flowed in) the m-th-place write-in word line, and the following currents i(n)BLare simultaneously passed through (or flowed in) the first to N-th-place bit lines. k0is the absolute value of the maximum value that k represents, and k in the expression (1) includes 0.

Specifically, the currents i(n)BLshown in the following Table 6 are passed through (or flowed in) the first to N-th-place bit lines simultaneously.

It is supposed that the normalized currents I(n)BLshown in the following Table 7 are passed through (or flowed in) the bit lines BLn.

FIG. 18Aschematically shows the values of the coefficients (tap-gains) g(0) and g(k) before addition in each bit line BLn(n=1 to 8) by the arrow marks, andFIG. 18Bschematically shows the values of the coefficients (tap-gains) G(n) after addition in each bit line BLnby the arrow marks. InFIG. 18B, the arrow marks G(−2), G(−1), G(+1) and G(+2) mean the coefficients (tap-gains) after addition in the second-place first dummy line DL12constituting the group of the first dummy lines, the first-place first dummy line DL11constituting the group of the first dummy lines, the first-place second dummy line DL21constituting the group of the second dummy lines and the second-place second dummy line DL22constituting the group of the second dummy lines. The following Table 8 andFIG. 19show the normalized currents i(n)BLto be passed through (or flowed in) the bit lines BLnand the dummy lines DL11, DL12, DL21and DL22.

Further,FIG. 20shows a graph obtained by superimposing the normalized magnetic fields [={i(S)·β2}/{(x−s)2+β2}] in the X-axis direction, obtained on the basis of the expression (7) and “s” and “i(s)” in Table 8. In this case, the currents flowing in the write-in conductor lines are adjusted so as to approximate to the Nyquist's first criterion as shown inFIG. 44. As an example, ±1 and ±2 are used as values of k, and the values shown in Table 2 are employed as coefficients (tap-gains) g(0) and g(k) in β=(h/d)=1.0 when approximation is based on the simple model inFIG. 39. This is also applicable toFIGS. 22 to 26to be explained later. As is clearly shown inFIG. 20, in the tunnel magnetoresistance device into which data “1” is to be written, the magnitude of the normalized magnetic field in the X-axis direction is almost “1”, and in the tunnel magnetoresistance device into which data “0” is to be written, the magnitude of the normalized magnetic field in the X-axis direction is almost “−1”. That is, it is seen that even when data are simultaneously written into the eight tunnel magnetoresistance devices arranged in parallel, no erroneous data writing occurs.

FIG. 21Bshows a graph obtained by superimposing the normalized magnetic fields in the X-axis direction likeFIG. 20, when the normalized currents I(n)BLshown in Table 7 are passed through (or flowed in) the bit lines BLn.FIG. 21Ashows the normalized currents i(n)BLto be passed through (or flowed in) the bit lines BLn. As is clearly shown inFIG. 21B, in the tunnel magnetoresistance device into which data “1” is to be written, the magnitude of the normalized magnetic field in the X direction cannot be “1” in some cases, and in the tunnel magnetoresistance device into which data “0” is to be written, the magnitude of the normalized-magnetic field in the X direction cannot be “−1” in some cases. That is, it is seen that when data are simultaneously written into the eight tunnel magnetoresistance devices arranged in parallel, erroneous data writing occurs.

When none of the dummy lines DL11, DL12, DL21and DL22is provided, a graph obtained by superimposing the normalized magnetic fields [={i(t)·βp2}/{(x−t)2+β2}] in the X-axis direction, obtained on the basis of the expression (7) and “t” and “i(t)” in Table 8, is as shown inFIG. 22. As is clearly shown inFIG. 22, in the tunnel magnetoresistance device into which data “1” is to be written, the magnitude of the normalized magnetic field in the X-axis direction is almost “1”, and in the tunnel magnetoresistance device into which data “0” is to be written, the magnitude of the normalized magnetic field in the X-axis direction is almost “−1”. That is, it is seen that even when data are simultaneously written into the eight tunnel magnetoresistance devices arranged in parallel, no erroneous data writing occurs. It is also seen that providing dummy lines is not essential.

It is supposed that the normalized currents I(n)BLshown in the following Table 9 are passed through (or flowed in) the bit lines BLn. Further, the following Table 9 shows the normalized currents i(n)BLthat are passed through (or flowed in) the bit lines BLnand the dummy lines DL11, DL12, DL21and DL22.

Further,FIG. 23shows a graph obtained by superimposing the normalized magnetic fields [={i(S)·β2}/{(X−S)2+β2}] in the X-axis direction, obtained on the basis of the expression (7) and “s” and “i(s)” in Table 9. As is clearly shown inFIG. 23, in the tunnel magnetoresistance device into which data “1” is to be written, the magnitude of the normalized magnetic field in the X-axis direction is almost “1”, and in the tunnel magnetoresistance device into which data “0” is to be written, the magnitude of the normalized magnetic field in the X-axis direction is almost “−1”. That is, it is seen that even when data are simultaneously written into the eight tunnel magnetoresistance devices arranged in parallel, no erroneous data writing occurs.

When none of the dummy lines DL11, DL12, DL21and DL22is provided,FIG. 24shows a graph obtained by superimposing the normalized magnetic fields [={i(t)·β2}/{(x−t)2+β2}] in the X-axis direction, obtained on the basis of the expression (7) and “t” and “i(t)” in Table 9. As is also clearly shown inFIG. 24, in the tunnel magnetoresistance device into which data “1” is to be written, the magnitude of the normalized magnetic field in the X-axis direction is almost “1”, and in the tunnel magnetoresistance device into which data “0” is to be written, the magnitude of the normalized magnetic field in the X-axis direction is almost “−1”. That is, it is seen that even when data are simultaneously written into the eight tunnel magnetoresistance devices arranged in parallel, no erroneous data writing occurs. It is also seen that providing dummy lines is not essential.

It is supposed that the normalized currents I(n)BLshown in the following Table 10 are passed through (or flowed in) the bit lines BLn. Further, the following Table 10 shows the currents i(n)BLthat are passed through (or flowed in) the bit lines BLnand the

Further,FIG. 25shows a graph obtained by superimposing the normalized magnetic fields [={i(s)·β2}/{(x−s)2+β2}] in the X-axis direction, obtained on the basis of the expression (7) and “s” and “i(s)” in Table 10. As is clearly shown inFIG. 25, in the tunnel magnetoresistance device into which data “1” is to be written, the magnitude of the normalized magnetic field in the X-axis direction is almost “1”, and in the tunnel magnetoresistance device into which data “0” is to be written, the magnitude of the normalized magnetic field in the X-axis direction is almost “−1”. That is, it is seen that even when data are simultaneously written into the eight tunnel magnetoresistance devices arranged in parallel, no erroneous data writing occurs.

When none of the dummy lines DL11, DL12, DL21and DL22is provided,FIG. 26shows a graph obtained by superimposing the normalized magnetic fields [={i(t)·β2}/{(x−t)2+β2}] in the X-axis direction, obtained on the basis of the expression (7) and “t” and “i(t)” in Table 10. As is also clearly shown inFIG. 26, in the tunnel magnetoresistance device into which data “1” is to be written, the magnitude of the normalized magnetic field in the X-axis direction is almost “1”, and in the tunnel magnetoresistance device into which data “0” is to be written, the magnitude of the normalized magnetic field in the X-axis direction is almost “−1”. That is, it is seen that even when data are simultaneously written into the eight tunnel magnetoresistance devices arranged in parallel, no erroneous data writing occurs. It is also seen that providing dummy lines is not essential.

FIGS. 27A and 27BandFIGS. 28A and 28Bshow “eye” patterns when β=(h/d)=1.0. An “eye” pattern is generally used for evaluating equalization characteristics in the field of digital transmission. InFIGS. 27A and 27BandFIGS. 28A and 28B, the unit of values in the axis of abscissas is “d”.

FIG. 27Ashows a superimposition of the magnetic fields generated by a random current IBLor current −IBL(having the values of ±1) flowing in the bit lines when an infinite number of the tunnel magnetoresistance devices are arranged along the write-in word line. That is,FIG. 27Ashows a superimposition of the magnetic fields before equalization.

FIG. 27Bshows a superimposition of the magnetic fields generated by a random current IBLor current −IBL(having the values of ±1), as a main magnetic field generating current ±g(0)·IBL, flowing in the bit lines and further by the first compensatory magnetic field generating currents ±g(±1)·IBLflowing in the bit lines, when an infinite number of the tunnel magnetoresistance devices are arranged along the write-in word line. That is,FIG. 27Bshows a case where an FIR filter of three taps is constituted.

FIG. 28Ashows a superimposition of the magnetic fields generated by a random current IBLor current −IBL(having the values of ±1), as a main magnetic field generating current ±g(0)·IBL, flowing in the bit lines and further by the first compensatory magnetic field generating currents ±g(±1)·IBLand the second compensatory magnetic field generating currents ±g(±2)·IBLflowing in the bit lines, when an infinite number of the tunnel magnetoresistance devices are arranged along the write-in word line. That is,FIG. 28Ashows a case where an FIR filter of five taps is constituted.

FIG. 28Bshows a superimposition of the magnetic fields generated by a random current IBLor current −IBL(having the values of ±1), as a main magnetic field generating current ±g(0)·IBL, flowing in the bit lines and further by the first compensatory magnetic field generating currents ±g(±1)·IBL, the second compensatory magnetic field generating currents ±g(±2)·IBLand the third compensatory magnetic field generating currents ±g(3)·IBLflowing in the bit lines, when an infinite number of the tunnel magnetoresistance devices are arranged along the write-in word line. That is,FIG. 28Bshows a case where an FIR filter of seven taps is constituted.

These “eye” pattern drawings show the following. When β=(h/d)=1.0, if the spatial FIR filter is not constituted, the magnetic fields interfere with one another to a great extent, so that parallel-data-writing in the tunnel magnetoresistance devices is not possible. However, if at least a FIR filter of three taps is constituted, the interference of the magnetic fields is suppressed, and parallel-data-writing in the tunnel magnetoresistance devices is possible. When an FIR filter of five taps and an FIR filter of seven taps are constituted, the interference of the magnetic fields is suppressed to a greater extent.

FIG. 29Ashows a drawing of an “eye” pattern similar to that inFIG. 27Abut when β=(h/d)=0.5, andFIG. 29Bshows an “eye” pattern similar to that inFIG. 27Bbut when β=(h/d)=0.5. For example, it is supposed that data can be written into a tunnel magnetoresistance device into which data is to be written, at a magnetic field magnitude of 0.5 or more. In this case, it is seen that a case where no data is written into a tunnel magnetoresistance device in error before equalization occurs at a constant rate but that, if an FIR filter of three taps is constituted, such a failure in wiring does not occur.

Further,FIGS. 30,31and32show “eye” patterns when β=(h/d)=1.0.FIG. 30shows a superimposition of the magnetic fields generated by a random current IBLor current −IBL(having values of ±1) flowing in the bit lines when the eight tunnel magnetoresistance devices are arranged along the write-in word line. That is,FIG. 30shows a superimposition of the magnetic fields before equalization.FIG. 31shows a superimposition of the magnetic fields generated by a random current IBLor current −IBL(having values of ±1), as a main magnetic field generating current ±g(0)·IBL, flowing in the bit lines and by the first compensatory magnetic field generating currents ±g(±1)·IBLflowing in the bit lines, in a case where one dummy line DL1is provided outside the first bit lines, one dummy line DL2is provided outside the eighth bit line and the eight tunnel magnetoresistance devices are arranged along the write-in word line. That is,FIG. 31shows a case where an FIR filter of three taps is constituted. Further,FIG. 32shows a case where an FIR filter of three taps is constituted without providing the dummy lines. From a comparison betweenFIG. 31andFIG. 32, it is seen that providing dummy lines is not essential.

For writing data into the tunnel magnetoresistance device in the nonvolatile magnetic memory device in Example 5, first, the open/close circuit SWRWL1is brought into an ON-state, and a current IRWLis passed through (or flowed in) the first write-in word line RWL1from the write-in word line current source RS1. And, for example, the currents shown in Table 6 are simultaneously passed through (or flowed in) the first to eighth bit lines BL1to BL8. These procedures are consecutively repeated from the second write-in word line RWL2to the M-th-place write-in word line RWLM.

In writing data into the tunnel magnetoresistance device in the nonvolatile magnetic memory device of Example 5, erroneous data writing into an adjacent tunnel magnetoresistance device can be reliably prevented.

Example 6 is concerned with the nonvolatile magnetic memory according to the second aspect of the present invention.FIG. 33shows an equivalent circuit diagram of the nonvolatile magnetic memory device in Example 6.

As shown inFIG. 33, the nonvolatile magnetic memory device in Example 6 has a nonvolatile magnetic memory array comprising;

(A) write-in word lines RWLmthat are M in number (m=1, 2, . . . M, M≧2, and M=32 in Example 6), extending in a first direction,

(B) bit line(s) BLnthat is(are) N in number (n=1, 2, . . . N, N≧1, and N=8 in Example 6), extending in a second direction different from the first direction, and

(C) tunnel magnetoresistance devices TMJ that are N×M (=8×32) in number, as explained above, formed in the overlap region of the write-in word lines RWLmand the bit line BLn.

When data is written into the tunnel magnetoresistance device TMJ(m,n)positioned in the overlap region of the m-th-place write-in word line RWLm(m is one of 1, 2, . . . M) and the n-th-place bit line BLn(n is one of 1, 2, . . . N), the current I(n)BLis passed through (or flowed in) the n-th-place bit line BLn, and the current g(0)·I(m)RWL[g(0):coefficient] is passed through (or flowed in) the m-th-place write-in word line RWLm. Further, together with these, the current g(k)·I(m)RWL[g(k):coefficient] is passed through (or flowed in) the p-th-place write-in word line RWLp(p=n+k, k represents ±1, ±2, . . . , k in Example 6 represents a value of −2, −1, 1, 2, and the total number of the lines is K).

When the magnetic fields, which are supposed to be formed in the m-th-place write-in word line RWLmand the write-in word lines RWLPthat are K in number by the currents I(m)RWL, is assumed to be discrete pulse response, and when the coefficients g(0) and g(k) are assumed to be tap-gains, a spatial FIR filter is constituted of the m-th-place write-in word line RWLmand the write-in word lines RWLpthat are K in number.

Further, the coefficients g(0) and g(k) are defined such that data is written into the tunnel magnetoresistance device TMJ(m,n)positioned in the overlap region of the m-th-place write-in word line RWLmand the n-th-place bit line BLnand data are not written into the tunnel magnetoresistance devices TMJ(p,n)positioned in the overlap regions of the n-th-place bit line BLnand the write-in word lines RWLpthat are K in number by means of a synthetic magnetic field based on a magnetic field (main magnetic field) generated by the current g(0)·I(m)RWLflowing in the m-th-place write-in word line RWPm, magnetic fields (compensatory magnetic fields) generated by the currents g(k)·I(m)RWLflowing in the write-in word lines RWLpthat are K in number, and a magnetic field generated by the current I(n)BLflowing in the n-th-place bit line BLn.

When the value of k represents ±1 and ±2 as examples, and when a simple model inFIG. 39is used for approximation, the values of g(−2), g(−1), g(0), g(1) and g(2) when β=(h/d)=1.0 are as shown in Table 2.

The absolute value k0of the maximum value that k represents is 2. Further, the value of m and the value of K have a relationship as shown in the following Table 11.

Meanwhile, the value of g(−2) and the value of g(2) are the same, and the value of g(−1) and the value of g(1) are the same. In the following explanation, therefore, the current source for letting the g(−1)·IRWLflow and the current source for letting the g(1)·IRWLflow are constituted of one current source, and the current source for letting the g(−2)·IRWLflow and the current source for letting the g(2)·IRWLflow are constituted of one current source. This will be also applicable to Examples 7 to 10. Since the value of I(m)RWLis determined to be constant regardless of any value of m, it will be shown as IRWLhereinafter. Further, since the coefficient g(1) and the coefficient g(−1) have the same value, they will be shown as g(1) hereinafter, and since the coefficient g(2) and the coefficient g(−2) have the same value, they will be shown as g(2) hereinafter.

That is, each write-in word line RWLmis provided with a current source unit RCSmfor letting the current g(0)·I(m)RWL, the current g(1)·I(m)RWLand the current g(2)·I(n)RWLflow in the write-in word line RWLm.

Each current source unit RCSmis provided with open/close circuits SWRWLm−i(i=1, 2, 3) constituted of a MOS-type FET each, and one of three currents, the current g(0)·IRWL, the current g(1)·IRWLand the current g(2)·IRWL, can be passed through (or flowed in) the write-in word line RWLmfrom the current source unit RCSmby the ON/OFF operation of the open/close circuits SWRWLm−i.FIG. 33shows the current source unit RCS1connected to the first write-in word line RWL1, while other current source units RCS2to RCS32have the same constitution as that of the current source unit RCS1.

The current g(0)·IRWLis a current (to be sometimes referred to as “main magnetic field generating current g(0)·IRWL”) for generating the magnetic field for writing data into the tunnel magnetoresistance devices that are N in number (tunnel magnetoresistance device TMJ(m,1)−tunnel magnetoresistance devices TMJ(m,N)) opposed to the m-th-place write-in word line RWLm.

The current g(1)·IRWLis a compensatory current (to be sometimes referred to as “first compensatory magnetic field generating current g(1)·IRWL”) for generating the compensatory magnetic field for preventing the destruction of data stored in the tunnel magnetoresistance device (tunnel magnetoresistance device TMJ(m,1)−tunnel magnetoresistance device TMJ(m,N)) opposed to the m-th-place write-in word line RWLm, which destruction is caused by the magnetic field generated as a result of the flowing of the main magnetic field generating current g(0)·IRWLin the write-in word line RWLm, when data are written into the tunnel magnetoresistance devices (tunnel magnetoresistance device TMJ(m′,1)−tunnel magnetoresistance device TMJ(m′,N)) opposed to the write-in word line RWLm′[m′=m±1, and 2≦m′≦(M−1)] adjacent to the m-th-place write-in word line RWLm.

Further, the current g(2)·IRWLis a compensatory current (to be sometimes referred to as “second compensatory magnetic field generating current g(2)·IRWL”) for generating the compensatory magnetic field for preventing the destruction of data stored in the tunnel magnetoresistance device (tunnel magnetoresistance device TMJ(m,1)−tunnel magnetoresistance device TMJ(m,N)) opposed to the m-th-place write-in word line RWLm, which destruction is caused by the magnetic field generated as a result of the flowing of the main magnetic field generating current g(0)·IRWLin the write-in word line RWLm″when data are written into the tunnel magnetoresistance devices (tunnel magnetoresistance device TMJ(m,1)−tunnel magnetoresistance device TMJ(m″,N)) opposed to the write-in word line RWLm″[m″=n±2, and 3≦m″≦(M−2)] adjacent to the m-th-place write-in word line RWLm.

That is, when the main magnetic field generating current g(0)·IRWLflows in the adjacent write-in word line RWLm′, the first compensatory magnetic field generating current g(1)·IRWLis passed through (or flowed in) the m-th-place write-in word line RWLm. Further, when the main magnetic field generating current g(0)·IRWLflows in the adjacent write-in word line RWLm″, the second compensatory magnetic field generating current g(2)·IRWLis passed through (or flowed in) the m-th-place write-in word line RWLm. When it is not required to write data into the tunnel magnetoresistance device TMJ, no current is passed through (or flowed in) any write-in word line.

The bit line BLnis connected to the bit line current source BSnthrough an open/close circuit SWBn−i(i=1, 2) constituted of a MOS-type FET. When the open/close circuit SWBn−iis in an ON-state, the current I(n)BL(specifically, current IBLor current −IBL) flows in the bit line BLn.

In the nonvolatile magnetic memory device in Example 6, when data is written into the tunnel magnetoresistance device TMJ, the open/close circuit SWB1−iis brought into an ON-state, to flow the current I(1)BLfrom the bit line current source BS1to the first bit line BL1. And, the main magnetic field generating current g(0)·IRWLis passed through (or flowed in) the first write-in word line RWL1, the first compensatory magnetic field generating current g(1)·IRWLis passed through (or flowed in) the second write-in word line WRL2, and the second compensatory magnetic field generating current g(2)·IRWLis passed through (or flowed in) the third write-in word line WRL3. These procedures are consecutively repeated from the second bit line BL2to the N-th-place bit line BLN.

Then, again, the current I(1)BLis passed through (or flowed in) the first bit line BL1from the bit line current source BS1. And, the main magnetic field generating current g(0)·IRWLis passed through (or flowed in) the second write-in word line RWL2, the first compensatory magnetic field generating currents g(1)·IRWLare passed through (or flowed in) the first write-in word line RWL1and the third write-in word line RWL3, and the second compensatory magnetic field generating current g(2)·IRWLis passed through (or flowed in) the fourth write-in word line RWL4. These procedures are consecutively repeated from the second bit line BL2to the N-th-place bit line BLN.

Further, again, the current I(1)BLis passed through (or flowed in) the first bit line BL1from the bit line current source BS1. And, the main magnetic field generating current g(0)·IRWLis passed through (or flowed in) the third write-in word line RWL3, the first compensatory magnetic field generating currents g(1)·IRWLare passed through (or flowed in) the second write-in word line RWL2and the fourth write-in word line RWL4, and the second compensatory magnetic field generating currents g(2)·IRWLare passed through (or flowed in) the first write-in word line RWL1and the fifth write-in word line RWL5. These procedures are consecutively repeated from the second bit line BL2to the N-th-place bit line BLN. Further, these procedures are consecutively repeated from the fourth write-in word line RWL4to the (M−2)-th-place write-in word line RWLM−2.

Then, again, the current I(1)BLis passed through (or flowed in) the first bit line BL1from the bit line current source BS1. And, the main magnetic field generating current g(0)·IRWLis passed through (or flowed in) the (M−1)-th-place write-in word line RWLM−1, the first compensatory magnetic field generating currents g(1)·IRWLare passed through (or flowed in) the (M−2)-th-place write-in word line RWLM−2and the M-th-place write-in word line RWLM, and the second compensatory magnetic field generating current g(2)·IRWLis passed through (or flowed in) the (M−3)-th-place write-in word line RWLM−3. These procedures are consecutively repeated from the second bit line BL2to the N-th-place bit line BLN.

Further, again, the current I(1)BLis passed through (or flowed in) the first bit line BL1from the bit line current source BS1. And, the main magnetic field generating current g(0)·IRWLis passed through (or flowed in) the M-th-place write-in word line RWLM, the first compensatory magnetic field generating current g(1)·IRWLis passed through (or flowed in) the (M−1)-th-place write-in word line RWLM−1, and the second compensatory magnetic field generating current g(2)·IRWLis passed through (or flowed in) the (M−2)-th-place write-in word line RWLM−2. These procedures are consecutively repeated from the second bit line BWL2to the N-th-place bit line BLN.

The above-explained operation is give as an example and may be modified as required. In Examples 7 to 10, further, data can be written into the tunnel magnetoresistance devices that are M×N in number substantially by the same method.

[Writing of Data into Tunnel Magnetoresistance Device TMJ(4,4)]

A case of writing data into the tunnel magnetoresistance device TMJ(4,4)connected to the fourth bit line BL4and positioned in the overlap region of the fourth bit line BL4and the fourth write-in word line RWL4(opposed to the fourth write-in word line RWL4) will be explained below as an example.

Immediately before data is written, all of the open/close circuits SWBn−i(n=1, 2, . . . N) are in an OFF-state. For starting the writing of data, the open/close circuit SWB4−iis brought into an ON-state, whereby the current I(4)BLis passed through (or flowed in) the fourth bit line BL4from the bit line current source BS4. In the current source unit RCS4, the open/close circuit SWRWLm−j(m=4, j=1) is selected to come into an ON-state, whereby the main magnetic field generating current g(0)·IRWLflows in the fourth write-in word line RWL4.

In the current source unit RCS3and the current source unit RCS5, the open/close circuits SWRWLm−j(m=3 and 5, j=2) are selected to come into an ON-state, whereby the first compensatory magnetic field generating currents g(1)·IRWLflow in the third write-in word line RWL3and the fifth write-in word line RWL5.

In the current source unit RCS2and the current source unit RCS6, the open/close circuits SWRWLm−j(m=2 and 6, j=3) are selected to come into an ON-state, whereby the second compensatory magnetic field generating currents g(2)·IRWLflow in the second write-in word line RWL2and the sixth write-in word line RWL6.

By the synthetic field generated as the result of the above [synthetic magnetic field of (1) the magnetic field generated by the main magnetic field generating current g(0)·IRWLflowing in the fourth write-in word line RWL4; (2) the magnetic fields generated by the first compensatory magnetic field generating currents g(1)·IRWLflowing in the third and fifth write-in word lines RWL3and RWL5; (3) the magnetic fields generated by the second compensatory magnetic field generating currents g(2)·IRWLflowing in the second and sixth write-in word lines RWL2and RWL6; and (4) the magnetic field generated by the current I(4)BLflowing in the fourth bit line BL4], the magnetization direction of the second ferromagnetic layer (memory layer)35in the tunnel magnetoresistance device TMJ(4,4)is changed, to record “1” or “0” in the second ferromagnetic layer (memory layer)35. On the other hand, the magnetization direction of the second ferromagnetic layer (memory layer)35of each of the tunnel magnetoresistance devices TMJ(2,4), TMJ(3,4), TMJ(5,4)and TMJ(6,4)remains unchanged by the above synthetic magnetic field.

The values of the current ±IBLand the current IRWLare determined beforehand such that the synthetic magnetic field in the second ferromagnetic layer (memory layer)35of the tunnel magnetoresistance device TMJ(4,4)has a value included in the region (OUT1) in the asteroid curve shown inFIG. 38, and that the synthetic magnetic field in the second ferromagnetic layer (memory layer)35of each of the tunnel magnetoresistance devices TMJ(2,4), TMJ(3,4), TMJ(5,4)and TMJ(6,4)has a values included in the region (IN) in the asteroid curve shown inFIG. 38.

There may be employed a constitution in which the magnetic field (HEA) in the easy-magnetization axis direction of the memory layer35is generated by the main magnetic field generating current g(0)·IRWLflowing in the write-in word line, and the magnetic field (HHA) in the hard-magnetization direction of the memory layer35is generated by the current ±IBLflowing in the bit line, or there may be employed a constitution in which the magnetic field (HHA) in the hard-magnetization direction of the memory layer35is generated by the main magnetic field generating current g(0)·IRWLflowing in the write-in word line, and the magnetic field (HEA) in the easy-magnetization axis direction of the memory layer35is generated by the current ±IBLflowing in the bit line. The above is also applicable to Examples 7 to 10 to be described later.

[Writing of Data into Tunnel Magnetoresistance Device TMJ(m,n)]

When data is written into the tunnel magnetoresistance device TMJ(m,n)opposed to the m-th-place write-in word line RWLm[m=3, 4, . . . (M−3), (M−2)] and positioned in the overlap region of the m-th-place write-in word line RWLmand the n-th-place bit line BLn(electrically connected to the n-bit line BLn), the following operation is carried out.

Immediately before data is written, all of the open/close circuits SWBn−1(n=1, 2, . . . N) are in an OFF-state. For starting the writing of data, the open/close circuit SWBn−iis brought into an ON-state, whereby the current I(n)BLis passed through (or flowed in) the n-th-place bit line BLnfrom the bit line current source BSn. In the current source unit RCSm, the open/close circuit SWRWLm−1is selected to come into an ON-state, whereby the main magnetic field generating current g(0)·IRWLflows in the m-th-place write-in word line RWLm.

In the current source unit RCSm−1and the current source unit RCSm+1, the open/close circuits SWRWLm′−2[m′=(m−1) and (m+1)] are selected to come into an ON-state, whereby the first compensatory magnetic field generating currents g(1)·IRWLflow in the (m−1)-th-place write-in word line RWLm−1and the (m+1)-th-place write-in word line RWLm+1.

Further, in the current source unit RCSm−2and the current source unit RCSm+2, the open/close circuits SWRWLm″−3[m″=(m−2) and (m+2)] are selected to come into an ON-state, whereby the second compensatory magnetic field generating currents g(2)·IRWLflow in the (m−2)-th-place write-in word line RWLm−2and the (m+1)-th-place write-in word line RWLm+2.

[Writing of Data into Tunnel Magnetoresistance Device TMJ(1,n)or TMJ(M,n)]

When data is written into the tunnel magnetoresistance device TMJ(P,n)opposed to the P-th-place write-in word line RWLP[P=1 or M] and electrically connected to the n-th-place bit line BLn, the following operation is carried out.

Immediately before data is written, all of the open/close circuits SWBn−1(n=1, 2, . . . N) are in an OFF-state. For starting the writing of data, the open/close circuit SWBn−iis brought into an ON-state, whereby the current I(n)BLis passed through (or flowed in) the n-th-place bit line BLnfrom the bit line current source BSn. In the current source unit RCSp, the open/close circuit SWRWLP−1is selected to come into an ON-state, whereby the main magnetic field generating current g(0)·IRWLflows in the P-th-place write-in word line RWLp.

In the current source unit RCS2or the current source unit RCSM−1, the open/close circuit SWRWLP′−2[P′=2 or (M−1)] is selected to come into an ON-state, whereby the first compensatory magnetic field generating current g(1)·IRWLflows in the second write-in word line RWL2or the (M−1)-th-place write-in word line RWLM−1.

Further, in the current source unit RCS3or the current source unit RCSM−2, the open/close circuit SWRWLP″−3[P″=3 or (M−2)] is selected to come into an ON-state, whereby the second compensatory magnetic field generating current g(2)·IRWLflows in the third write-in word line RWL3or the (M−2)-th-place write-in word line RWLM−2.

[Writing of Data into Tunnel Magnetoresistance Device TMJ(2,n)or TMJ(M−1,n)]

When data is written into the tunnel magnetoresistance device TMJ(P,n)opposed to the P-th-place write-in word line RWLP[P=2 or (M−1)] and electrically connected to the n-th-place bit line BLn, the following operation is carried out.

Immediately before data is written, all of the open/close circuits SWBn−i(n=1, 2, . . . N) are in an OFF-state. For starting the writing of data, the open/close circuit SWBn−iis brought into an ON-state, whereby the current I(n)BLis passed through (or flowed in) the n-th-place bit line BLnfrom the bit line current source BSn. In the current source unit RCSP, the open/close circuit SWRWLP−1is selected to come into an ON-state, whereby the main magnetic field generating current g(0)·IRWLflows in the P-th-place write-in word line RWLP.

In the current source unit RCS1and the current source unit RCS3, or in the current source unit RCSM−2and the current source unit BCSM, the open/close circuits SWRWLP′−2[P′=1 and 3, or P′=(M−2) or M] are selected to come into an ON-state, whereby the first compensatory magnetic field generating currents g(1)·IRWLflow in the first write-in word line RWL1and the third write-in word line RWL3, or in the (M−2)-th-place write-in word line RWLM−2and the M-th-place write-in word line RWLM.

Further, in the current source unit RCS4or the current source unit RCSM−3, the open/close circuit SWRWLP″−2[P″=4 or (M−3)] is selected to come into an ON-state, whereby the second compensatory magnetic field generating current g(2)·IRWLflows in the fourth write-in word line RWL4or the (M−3)-th-place write-in word line RWLM−3.

In the nonvolatile magnetic memory device in Example 6, when data is written into the tunnel magnetoresistance device TMJ(m,n), the main magnetic field generating current g(0)·IRWLis passed through (or flowed in) the write-in word line RWLmfrom the current source unit RCSm, and the compensatory magnetic field generating currents g(2)·IRWL, g(1)·IRWL, g(1)·IRWLand g(2)·IRWLare passed through (or flowed in) the write-in word lines RWLm−2, RWLm−1, RWLm+1and RWLm+2from the current source units RCSm−2, RCSm−1, RCSm+1, and RCSm+2. As a result, the destruction of data stored in the tunnel magnetoresistance devices TMJ(m−2,n), TMJ(m−1,n), TMJ(m+1,n)and TMJ(m+2,n)opposed to the write-in word lines RWLm−2, RWLm−1, RWLm+1and RWLm+2can be reliably prevented.

Example 7 is a variant of Example 6.FIG. 34shows an equivalent circuit diagram of a nonvolatile magnetic memory device in Example 7.

In the nonvolatile magnetic memory device explained in Example 6, for example, the main magnetic field is generated by the current flowing in the first write-in word line RWL1or the M-th-place write-in word line RWLM[magnetic field generated by the current g(0)·I(1)RWLor current g(0)·I(M)RWL], and the compensatory magnetic fields are generated by the currents flowing in the second and third write-in word lines RWL2and RWL3or by the currents flowing in the (M−2)-th-place and (M−1)-th-place write-in word lines RWL(M−2)and RWL(M−1)[magnetic fields generated by the current g(1)·I(1)RWLand the current g(2)·I(1)RWL, or the current g(−2)·I(M)RWLand g(−1)·I(M)RWL], while these compensatory magnetic fields become asymmetric, for example, with regard to the first write-in word line RWL1or the M-th-place write-in word line RWLMas a base.

In the nonvolatile magnetic memory device in Example 7, therefore, when the absolute value of the maximum value that k represents is k0(k0=2 in Example 7),

a group of first dummy lines that are k0in number (first dummy lines DL11and DL12) is provided outside the first write-in word line RWL1and in parallel with the first write-in word line RWL1,

a group of second dummy lines that are k0in number (second dummy lines DL21and DL22) is provided outside the M-th-place write-in word line RWLMand in parallel with the M-th-place write-in word line RWLM, and

a current g(k)·I(m)RWLis passed through (or flowed in) the [(1−m)+|k|]-th-place first dummy line constituting the group of the first dummy lines or the [m−M+|k|]-th-place second dummy line constituting the group of the second dummy lines.

Specifically, when the main magnetic field generating current g(0)·IRWLis passed through (or flowed in) the first write-in word line RWL1, the first compensatory magnetic field generating current g(−1)·IRWLis passed through (or flowed in) the [(1−m)+|k|]-th-place first dummy line DL11(m=1, k=−1, first-place first dummy line) constituting the group of the first dummy lines, and the second compensatory magnetic field generating current g(−2)·IRWLis passed through (or flowed in) the [(1−m)+|k|]-th-place first dummy line DL12(m=1, k=−2, and second-place first dummy line) constituting the group of the first dummy lines. Further, when the main magnetic field generating current g(0)·IRWLis passed through (or flowed in) the second write-in word line RWL2, the second compensatory magnetic field generating current g(−2)·IRWLis passed through (or flowed in) the [(1−m)+|k|]-th-place first dummy line DL11(m=2, k=−2, first-place first dummy line) constituting the group of the first dummy lines.

When the main magnetic field generating current g(0)·IRWLis passed through (or flowed in) the M-th-place write-in word line RWLM, the first compensatory magnetic field generating current g(1)·IRWLis passed through (or flowed in) the [m−M+|k|]-th-place second dummy line DL21(m=M, k=1, first-place second dummy line) constituting the group of the second dummy lines, and the second compensatory magnetic field generating current g(2)·IRWLis passed through (or flowed in) the [m−M+|k|]-th-place second dummy line DL22(m=M, k=2, and second-place second dummy line) constituting the group of the second dummy lines. Further, when the main magnetic field generating current g(0)·IRWLis passed through (or flowed in) the (M−1)-th-place write-in word line RWLM−1, the second compensatory magnetic field generating current g(2)·IRWLis passed through (or flowed in) the [m−M+|k|]-th-place second dummy line DL21(m=M−1, k=2, first-place second dummy line) constituting the group of the second dummy lines.

The first-place first dummy line DL11constituting the group of the first dummy lines is connected to a first dummy line current source DLCS11, the second-place first dummy line DL12constituting the group of the first dummy lines is connected to a first dummy line current source DLCS12, the first-place second dummy line DL21constituting the group of the second dummy lines is connected to a second dummy line current source DLCS21, and the second-place second dummy line DL22constituting the group of the second dummy lines is connected to a second dummy line current source DLCS22.

The first dummy line current source DLCS11is provided with an open/close circuit SWDL-11−j(j=1, 2) constituted of a MOS-type FET, and by the ON/OFF operation of the open/close circuit SWDL-11−j, one of two currents, the current g(1)·IRWLand the current g(2)·IRWL, can be passed through (or flowed in) the first-place first dummy line DL11constituting the group of the first dummy lines from the first dummy line current source DLCS11. The second dummy line current source DLCS21is provided with an open/close circuit SWDL-21−j(j=1, 2) constituted of a MOS-type FET, and by the ON/OFF operation of the open/close circuit SWDL-21−j, one of two currents, the current g(1)·IRWLand the current g(2)·IRWLcan be passed through (or flowed in) the first-place second dummy line DL21constituting the group of the second dummy lines from the second dummy line current source DLCS21.

Further, the first dummy line current source DLCS12is provided with an open/close circuit SWDL-12−2constituted of a MOS-type FET, and by the ON/OFF operation of the open/close circuit SWDL-12−2, the current g(2)·IRWLcan be passed through (or flowed in) the second-place first dummy line DL12constituting the group of the first dummy lines from the first dummy line current source DLCS12. The second dummy line current source DLCS22is provided with an open/close circuit SWDL-22−2constituted of a MOS-type FET, and by the ON/OFF operation of the open/close circuit SWDL-22−2, the current g(2)·IRWLcan be passed through (or flowed in) the second-place second dummy line DL22constituting the group of the second dummy lines from the second dummy line current source DLCS22.

The constitution, structure and operation of the nonvolatile magnetic memory device in Example 7 can be the same as those of the nonvolatile magnetic memory device in Example 6 except for the above points, so that a detailed explanation thereof will be omitted. The values of the coefficients g(1), g(−1), g(2) and g(−2) can be determined so as to be the same as those in Example 7.

In the nonvolatile magnetic memory device in Example 7, the compensatory magnetic field for preventing the destruction of data stored in the tunnel magnetoresistance device becomes symmetric with regard to the first write-in word line RWL1, the second write-in word line RWL2, the (M−1)-th-place write-in word line RWLM−1or the M-th-place write-in word line RWLMas a base, so that the operation of writing data into the nonvolatile magnetic memory device is more stabilized.

Example 8 is also a variant of Example 6.FIG. 35shows an equivalent circuit diagram of a nonvolatile magnetic memory device in Example 8.FIG. 36shows an equivalent circuit diagram of a first current source unit51and a first switch circuit51A, a second current source unit52and a second switch circuit52A, a third current source unit53and a third switch circuit53A, a fourth current source unit54and a fourth switch circuit54A, and a fifth current source unit55and a fifth switch circuit55A in the nonvolatile magnetic memory device in Example 8.

In Example 8, the current source is not constituted of the current source units that are N in number, but instead constituted of the first current source unit51, the second current source unit52, the third current source unit53, the fourth current source unit54and the fifth current source unit55. The first current source unit51for letting the main magnetic field generating current g(0)·IRWLflow in the write-in word line RWLmis connected to the write-in word lines RWLmthat are M in number through the first switch circuit51A (constituted of open/close circuits SW SWMRWL-1–SWMRL-32constituted of a MOS-type FET each). The second current source unit52and the third current source unit53for letting the first compensatory magnetic field generating current g(1)·IRWLflow in the write-in word lines RWLmare connected to the write-in word lines RWLmthat are M in number through the second switch circuit52A (constituted of open/close circuits SW SWCRWL2-1–SWCRWL2-32constituted of a MOS-type FET each) and the third switch circuit53A (constituted of open/close circuits SW SWCRWL3-1–SWCRWL3-32constituted of a MOS-type FET each). Further, the fourth current source unit54and the fifth current source unit55for letting the second compensatory magnetic field generating current g(2)·IRWLflow in the write-in word lines RWLmare connected to the write-in word lines RWLmthat are M in number through the fourth switch circuit54A (constituted of open/close circuits SW SWCRWL4-1–SWCRWL4-32constituted of a MOS-type FET each) and the fifth switch circuit54A (constituted of open/close circuits SW SWCRWL5-1–SWCRWL5-32constituted of a MOS-type FET each).

The constitution, structure and operation of the nonvolatile magnetic memory device in Example 8 can be the same as those of the nonvolatile magnetic memory device in Example 6 except for the above points, so that a detailed explanation thereof will be omitted. In Example 8, the above constitution is employed, so that the number of the current source units can be decreased, and that the constitution of the nonvolatile magnetic memory device can be simplified.

[Writing of Data into Tunnel Magnetoresistance Device TMJ(m,n)]

When data is written into the tunnel magnetoresistance device TMJ(m,n)opposed to the m-th-place write-in word line WRLm[m=3, 4, . . . (M−2)] and electrically connected to the n-th-place bit line BLn, the following operation is carried out.

Immediately before data is written, all of the open/close circuits SWBn−i(n=1, 2, . . . N) are in an OFF-state. For starting the writing of data, the open/close circuit SWBn−iis brought into an ON-state, whereby the current I(n)BLis passed through (or flowed in) the n-th-place bit line BLnfrom the bit line current source BSn. In the first current source unit51, the open/close circuit SWMRWL−mconstituted of a MOS-type FET constituting the first switch circuit51A is selected to come into an ON-state, whereby the main magnetic field generating current g(0)·IRWLflows in the m-th-place write-in word line RWLm.

In the second current source unit52, the open/close circuit SWCRWL-2(m−1)constituting the second switch circuit52A is selected to come into an ON-state. In the third current source unit53, the open/close circuit SWCRWL3-(m+1)constituting the third switch circuit53A is selected to come into an ON-state, whereby the first compensatory magnetic field generating currents g(1)·IRWLflow in the (m−1)-th-place write-in word line RWLm−1and the (m+1)-th-place write-in word line RWLm+1. Further, in the fourth current source unit54, the open/close circuit SWCRWL4-(m−2)constituting the fourth switch circuit54A is selected to come into an ON-state, and in the fifth current source unit55, the open/close circuit SWCRWL5-(m+2)constituting the fifth switch circuit55A is selected to come into an ON-state, whereby the second compensatory magnetic field generating currents g(2)·IRWLflow in the (m−2)-th-place write-in word line RWLm−2and the (m+2)-th-place write-in word line RWLm+2.

By the synthetic magnetic field generated as the result of the above (synthetic magnetic field of (1) the magnetic field generated by the main magnetic field generating current g(0)·IRWLflowing in the m-th-place write-in word line RWLm; (2) the magnetic fields generated by the first compensatory magnetic field generating currents g(1)·IRWLflowing in the (m−1)-th-place and (m+1)-th-place write-in word lines RWLm−1and RWLm+1; (3) the magnetic fields generated by the second compensatory magnetic field generating currents g(2)·IRWLflowing in the (m−2)-th-place and (m+2)-th-place write-in word line RWLm−2and RWLm+2; and (4) the magnetic field generated by the current I(n)BLflowing in the n-th-place bit line BLn], the magnetization direction of the second ferromagnetic layer (memory layer)35in the tunnel magnetoresistance device TMJ(m,n)is changed, to record “1” or “0” in the second ferromagnetic layer (memory layer)35. On the other hand, the magnetization direction of the second ferromagnetic layer (memory layer)35of each of the tunnel magnetoresistance devices TMJ(m−2,n), TMJ(m−1,n), TMJ(m+1,n)and TMJ(m+2,n)remains unchanged by the above synthetic magnetic field.

[Writing of Data into Tunnel Magnetoresistance Device TMJ(1,n)or TMJ(M,n)]

When data is written into the tunnel magnetoresistance device TMJ(P,n)opposed to the P-th-place write-in word line RWLP[P=1 or M] and electrically connected to the n-th-place bit line BLn, the following operation is carried out.

Immediately before data is written, all of the open/close circuits SWBn−i(i=1, 2, . . . N) are in an OFF-state. For starting the writing of data, the open/close circuit SWBn−iis brought into an ON-state, whereby the current I(n)BLis passed through (or flowed in) the n-th-place bit line BLnfrom the bit line current source BSn. In the first current source unit51, the open/close circuit SWMRWL-Pconstituted of a MOS-type FET constituting the first switch circuit51A is selected to come into an ON-state, whereby the main magnetic field generating current g(0)·IRWLflows in the P-th-place write-in word line RWLP.

In the second current source unit52, the open/close circuit SWCRWL2-(M−1)constituting the second switch circuit52A is selected to come into an ON-state or the open/close circuit SWCRWL3-2constituting the third switch circuit53A is selected to come into an ON-state, whereby the first compensatory magnetic field generating current g(1)·IRWLflows in the second write-in word line RWL2or the (M−1)-th-place write-in word line RWLM−1. Further, the open/close circuit SWCRWL4-(M−2)constituting the fourth switch circuit54A is selected to come into an ON-state, or the open/close circuit SWCRWL5-3constituting the fifth switch circuit55A is selected to come into an ON-state, whereby the second compensatory magnetic field generating current g(2)·IRWLflows in the third write-in word line RWL3or the (M−2)-th-place write-in word line RWLM−2.

[Writing of Data into Tunnel Magnetoresistance Device TMJ(2,n)or TMJ(M−1,n)]

When data is written into the tunnel magnetoresistance device TMJ(P,n)opposed to the P-th-place write-in word line RWLP[P=2 or (M−1)] and electrically connected to the n-th-place bit line BLn, the following operation is carried out.

Immediately before data is written, all of the open/close circuits SWBn−i(i=1, 2, . . . N) are in an OFF-state. For starting the writing of data, the open/close circuit SWBn−iis brought into an ON-state, whereby the current I(n)BLis passed through (or flowed in) the n-th-place bit line BLnfrom the bit line current source BSn. In the first current source unit51, the open/close circuit SWMRWL-Pconstituting the first switch circuit51A is selected to come into an ON-state.

In the second current source unit52and the third current source unit53, the open/close circuit SWCRWL2-(P−1)and the open/close circuit SWCRWL3-(P+1)are selected to come into an ON-state, whereby the first compensatory magnetic field generating currents g(1)·IRWLflow in the first write-in word line RWL1and the third write-in word line RWL3or in the (M−2)-th-place write-in word line RWLM−2and the M-th-place write-in word line RWLM. Further, in the fourth current source unit54or the fifth current source unit55, the open/close circuit SWCRWL4-(P−2)constituting the fourth switch circuit54A or the open/close circuit SWCRWL5-4constituting the fifth switch circuit55A is selected to come into an ON-state, whereby the second compensatory magnetic field generating current g(2)·IRWLflows in the fourth write-in word line RWL4or the (M−3)-th-place write-in word line RWLM−3.

In the nonvolatile magnetic memory device in Example 8, when data is written into the tunnel magnetoresistance device TMJ(m,n), the main magnetic field generating current g(0)·IRWLis passed through (or flowed in) the write-in word line RWLmfrom the first current source unit51, and the compensatory magnetic field generating currents g(2)·IRWL, g(1)·IRWL, g(1)·IRWLand g(2)·IRWLare passed through (or flowed in) the write-in word lines RWLm−2, RWLm−1, RWLm+1and RWLm+2from the fourth current source unit54, the second current source unit52, the third current source unit53and the fifth current source unit55. As a result, the destruction of data stored in the tunnel magnetoresistance devices TMJ(m−2,n), TMJ(m−1,n), TMJ(m+1,n)and TMJ(m+2,n)opposed to the write-in word lines RWLm−2, RWLm−1, RWLm+1and RWLm+2can be reliably prevented.

Example 9 is a variant of Example 8.FIG. 37shows an equivalent circuit diagram of a nonvolatile magnetic memory in Example 9.

In the nonvolatile magnetic memory device explained in Example 8, for example, the main magnetic field is generated by the current flowing in the first write-in word line RWL1or in the M-th-place write-in word line RWLM[magnetic field generated by the current g(0)·IRWLor the current g(0)·I(M)RWL], and the compensatory magnetic fields are generated by the currents flowing in the second and third write-in word lines RWL2and RWL3or in the (M−2)-th-place and (M−1)-th-place write-in word lines RWL(M−2)and RWL(M−1)[magnetic field generated by the current g(1)·I(1)RWLand the current g(2)·I(1)RWL, or by the current g(−2)·I(M)BLand the current g(−1)·I(M)BL]. The above compensatory magnetic fields are asymmetric, for example, with regard to the first write-in word line RWL1or the M-th-place write-in word line RWLMas a base.

In the nonvolatile magnetic memory device in Example 9, therefore, when the absolute value of the maximum value that k represents is k0like Example 7 (k0=2 in Example 9),

a group of first dummy lines that are k0in number (first dummy lines DL11and DL12) is provided outside the first write-in word line RWL1and in parallel with the first write-in word line RWL1,

a group of second dummy lines that are k0in number (second dummy lines DL21and DL22) is provided outside the M-th-place write-in word line RWLMand in parallel with the M-th-place write-in word line RWLM, and

a current g(k)·IRWLis passed through (or flowed in) the [(1−m)+|k|]-th-place first dummy line constituting the group of the first dummy lines or the [m−M+|k|]-th-place second dummy line constituting the group of the second dummy lines.

Specifically, like Example 7, when the main magnetic field generating current g(0)·IRWLis passed through (or flowed in) the first write-in word line RWL1, the first compensatory magnetic field generating current g(−1)·IRWLis passed through (or flowed in) the [(1−m)+|k|]-th-place first dummy line DL11(m=1, k=−1, first-place first dummy line) constituting the group of the first dummy lines, and the second compensatory magnetic field generating current g(−2)·IRWLis passed through (or flowed in) the [(1−m)+|k|]-th-place first dummy line DL12(m=1, k=−2, and second-place first dummy line) constituting the group of the first dummy lines. Further, when the main magnetic field generating current g(0)·IRWLis passed through (or flowed in) the second write-in word line RWL2, the second compensatory magnetic field generating current g(−2)·IRWLis passed through (or flowed in) the [(1−m)+|k|]-th-place first dummy line DL11(m=2, k=−2, first-place first dummy line) constituting the group of the first dummy lines.

When the main magnetic field generating current g(0)·IRWLis passed through (or flowed in) the M-th-place write-in word line RWLM, the first compensatory magnetic field generating current g(1)·IRWLis passed through (or flowed in) the [m−M+|k|]-th-place second dummy line DL21(m=M, k=1, first-place second dummy line) constituting the group of the second dummy lines, and the second compensatory magnetic field generating current g(2)·IRWLis passed through (or flowed in) the [m−M+|k|]-th-place second dummy line DL22(m=M, k=2, and second-place second dummy line) constituting the group of the second dummy lines. Further, when the main magnetic field generating current g(0)·IRWLis passed through (or flowed in) the (M−1)-th-place write-in word line RWLM−1, the second compensatory magnetic field generating current g(2)·IRWLis passed through (or flowed in) the [m−M+|k|]-th-place second dummy line DL21(m=M−1, k=2, first-place second dummy line) constituting the group of the second dummy lines.

The first-place first dummy line DL11constituting the group of the first dummy lines is connected to the third current source unit53through an open/close circuit that is not shown, and further, is connected to the fifth current source unit55through an open/close circuit that is not shown. Further, the first-place second dummy line DL21constituting the group of the second dummy lines is connected to the second current source unit52through an open/close circuit that is not shown, and further, is connected to the fourth current source unit54through an open/close circuit that is not shown. The second-place first dummy line DL12constituting the group of the first dummy lines is connected to the fifth current source unit55through an open/close circuit that is not shown. The second-place second dummy line DL22constituting the group of the second dummy lines is connected to the fourth current source unit54through an open/close circuit that is not shown.

The constitution, structure and operation of the nonvolatile magnetic memory device in Example 9 can be the same as those of the nonvolatile magnetic memory device in Example 8 except for the above points, so that a detailed explanation thereof is omitted. The operation of the dummy lines can be substantially the same as that explained in Example 7, so that a detailed explanation thereof is omitted.

Example 10 is concerned with the method for writing data into a tunnel magnetoresistance device in a nonvolatile magnetic memory device (more specifically, a nonvolatile magnetic memory device having TMR-type MRAM) according to the second aspect of the present invention.

The nonvolatile magnetic memory device in Example 10 has the constitution and the structure that are explained in Example 7. While each write-in word line RWLmis provided with a current source unit RCSmlike Example 7, a circuit (not shown) for adding the current g(0)·IRWL, the current g(1)·IRWLand the current g(2)·IRWLis provided between the current source unit RCSmand the write-in word line RWLm. Further, similarly, circuits (not shown) for adding the currents are provided between the first dummy line current source DLCS11and the first-place first dummy line DL11and between the second dummy line current source DLCS21and the first-place second dummy line DL21.

In Example 10, the current I(n)BLis passed through (or flowed in) the n-th-place bit line, and the following currents i(m)RWLare simultaneously passed through (or flowed in) the first to M-th-place write-in word lines. k0is the absolute value of the maximum value that k represents, and k in the expression (2) includes 0.

Specifically, the currents i(m)RWLshown in the following Table 12 are simultaneously passed through (or flowed in) the first to M-th-place write-in word lines. Table 12 shows all of the currents to be passed through (or flowed in) the dummy lines DL12and DL11and the first to sixth write-in word lines RWL1to RWL6, and shows part of the currents to be passed through (or flowed in) the seventh to tenth write-in word lines RWL7to RWL10. And, showing of the currents to be passed through (or flowed in) the 11th to 32nd write-in word lines RWL11to RWL32and the dummy lines DL21and DL22is omitted.

For writing data into the tunnel magnetoresistance device in the nonvolatile magnetic memory device in Example 10, the open/close circuit SWB1−iis brought into an ON-state, and the current I(1)BLis passed through (or flowed in) the first bit line BL1from the bit line current source BS1. And, for example, the currents shown in Table 12 are simultaneously passed through (or flowed in) the first to 32nd write-in word lines RWL1to RWL32. These procedures are consecutively repeated from the second bit line BL2to the N-th-place bit line BLN.

In writing data into the tunnel magnetoresistance device in the nonvolatile magnetic memory device in Example 10, the occurrence of erroneous data writing into adjacent tunnel magnetoresistance devices can be reliably prevented. In the nonvolatile magnetic memory device having the above-explained constitution, the current is passed through (or flowed in) the word line only unidirectionally, so that the same data is only written in a multiple-writing manner in the direction determined by the current flowing in the bit line. Unlike Example 5, therefore, it is not possible to write predetermined data in the tunnel magnetoresistance devices one by one in Example 10, and the use of the method of Example 10 is limited to erasing of data or multiple-writing of data. As explained in Example 5, it is not essential to provide the dummy lines.

While the present invention has been explained with reference to Examples hereinabove, the present invention shall not be limited thereto. The constitutions, structures and the like of the nonvolatile magnetic memory device, the current source and the dummy line current source and the materials for constituting the layers of the tunnel magnetoresistance device are given as examples and may be changed or modified as required.

In the examples, the coefficients g(0) and g(k) assumed to be tap-gains have identical values in all of the bit lines or all of the write-in word lines. However, the coefficients g(0) and g(k) assumed to be tap-gains may differ between one bit line and another or between one write-in word line and another.

Further, for example, the current source unit RCSmmay have a constitution in which it not only lets the currents g(0)·IRWL, g(1)·IRWLand g(2)·IRWLflow but also lets the currents −g(0)·IRWL, −g(1)·IRWLand −g(2)·IRWLflow, like the current source unit BCSn. In this case, the circuit constitution of the current source unit RCSmcan be substantially the same as the circuit constitution of the current source unit BCSn.

For reading data stored in the tunnel magnetoresistance device TMJ, a reference tunnel magnetoresistance device having the same structure and the same constitution as those of the tunnel magnetoresistance device TMJ may be provided in parallel with the first bit line and/or the N-th-place bit line and outside the first bit line and/or the N-th-place bit line. In this constitution, the bit line constituting the reference tunnel magnetoresistance device can work as a substitute for the dummy line.

The nonvolatile magnetic memory may comprise the following constitution.(1) A combination of the nonvolatile magnetic memory in Example 1 and the nonvolatile magnetic memory in Example 6.(2) A combination of the nonvolatile magnetic memory in Example 1 and the nonvolatile magnetic memory in Example 7.(3) A combination of the nonvolatile magnetic memory in Example 1 and the nonvolatile magnetic memory in Example 8.(4) A combination of the nonvolatile magnetic memory in Example 1 and the nonvolatile magnetic memory in Example 9.(5) A combination of the nonvolatile magnetic memory in Example 2 and the nonvolatile magnetic memory in Example 6.(6) A combination of the nonvolatile magnetic memory in Example 2 and the nonvolatile magnetic memory in Example 7.(7) A combination of the nonvolatile magnetic memory in Example 2 and the nonvolatile magnetic memory in Example 8.(8) A combination of the nonvolatile magnetic memory in Example 2 and the nonvolatile magnetic memory in Example 9.(9) A combination of the nonvolatile magnetic memory in Example 3 and the nonvolatile magnetic memory in Example 6.(10) A combination of the nonvolatile magnetic memory in Example 3 and the nonvolatile magnetic memory in Example 7.(11) A combination of the nonvolatile magnetic memory in Example 3 and the nonvolatile magnetic memory in Example 8.(12) A combination of the nonvolatile magnetic memory in Example 3 and the nonvolatile magnetic memory in Example 9.(13) A combination of the nonvolatile magnetic memory in Example 4 and the nonvolatile magnetic memory in Example 6.(14) A combination of the nonvolatile magnetic memory in Example 4 and the nonvolatile magnetic memory in Example 7.(15) A combination of the nonvolatile magnetic memory in Example 4 and the nonvolatile magnetic memory in Example 8.(16) A combination of the nonvolatile magnetic memory in Example 4 and the nonvolatile magnetic memory in Example 9.

In the examples, the coefficients g(0) and g(k) are used for the bit line and the write-in word line in view of explanations. However, the value of β=(h/d) generally differs between the bit line and the write-in word line. In the above combination, therefore, different coefficients are used like gBL(0) and gBL(k) as coefficients for the bit line and gRWL(0) and gRWL(k) as coefficients for the write-in word line.

Further, a plurality of the nonvolatile magnetic memory devices of the present invention may be arranged in parallel while using the write-in word line in common.

The line in which the compensatory current is to flow shall not be limited to the bit line or the write-in word line. There may be employed a constitution in which a dedicated line for magnetic field controlling is provided between a tunnel magnetoresistance device and a tunnel magnetoresistance device, and the spatial FIR filter is constituted of the dedicated line(s) And the bit line(s) or of the dedicated line(s) and the write-in word line(s).

Like MRAM disclosed in U.S. Pat. No. 5,940,319, there may be employed a structure in which that portion of the wiring (bit line or write-in word line) positioned above and/or below the tunnel magnetoresistance device which portion is not opposed to the tunnel magnetoresistance device is covered with a material for flux concentration material (for example, a soft magnetic material or a high-permeability material such as a cobalt-iron alloy, a nickel-iron alloy or an amorphous magnetic material), so that the flux concentration on the second ferromagnetic layer (memory layer)35can be improved.

In the nonvolatile magnetic memory device of the present invention, the spatial FIR filter assuming the magnetic fields, which are supposed to be formed in the n-th-place bit line and the bit lines that are K in number by the current I(n)BL, to be discrete pulse response and assuming the coefficients g(0) and g(k) to be tap-gains is constituted of the n-th-place bit line and the bit lines that are K in number, or the spatial FIR filter assuming the magnetic fields, which are supposed to be formed in the m-th-place write-in word line and the write-in word lines that are K in number by the current I(m)RWL, to be discrete pulse response and assuming the coefficients g(0) and g(k) to be tap-gains is constituted of the m-th-place write-in word line and the write-in word lines that are K in number. These coefficients g(0) and g(k) can be relatively easily obtained on the basis of a calculation method of the tap-gains in the FIR filter. By defining the coefficients g(0) and g(k), erroneous data writing into an adjacent tunnel magnetoresistance device can be reliably prevented. As a result, data can be reliably written into adjacent tunnel magnetoresistance devices, and there can be reliably prevented a condition in which the tunnel magnetoresistance device into which data is to be written comes into a so-called half-selection state.

Even in a case where an inversion threshold value of magnetization direction of the second ferromagnetic layer (memory layer) differs among the tunnel magnetoresistance devices caused by fluctuation in manufacturing process of the nonvolatile magnetic memory device or by temperature change, the occurrence of destruction of data in an adjacent tunnel magnetoresistance device can be reliably prevented, and the operation range where the tunnel magnetoresistance devices can well perform can be secured. As a result, when the production process is identical, the nonvolatile magnetic memory devices are improved in reliability and improved in yields, and the production cost can be decreased.

Further, the tunnel magnetoresistance devices can be more micro-fabricated than they have been, and nonvolatile magnetic memory devices having a large memory capacity can be materialized.

In the nonvolatile magnetic memory device of the present invention, there is an increase in power consumption in compensation for prevention of the interference caused by the magnetic field. However, the magnetic field can be controlled to such an extent that a necessary normal operation range can be secured, so that the increase in power consumption can be controlled.