Patent Publication Number: US-8120947-B2

Title: Spin torque transfer MRAM device

Description:
This application is a Continuation of U.S. patent application Ser. No. 11/752,157, filed May 22, 2007, now U.S. Pat. No. 7,573,736, which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     The present disclosure relates generally to the field of nonvolatile memory devices, and more specifically to an element of a magnetic random access memory (MRAM) device that uses spin torque transfer. 
     MRAM is a nonvolatile memory technology that uses magnetization to represent stored data. MRAMs are beneficial in that they retain stored data in the absence of electricity. Generally, MRAM includes a plurality of magnetic cells in an array. Each cell typically represents one bit of data. Included in the cells are magnetic elements. A magnetic element may include two ferromagnetic “plates” (or layers upon a semiconductor substrate) each of which has a magnetization direction (or orientation of magnetic moments) associated with it. The two ferromagnetic plates are separated by a thin non-magnetic layer. 
     More specifically, MRAM cells are often based on a magnetic tunnel junction (MTJ) element (also known as tunnel magnetoresistance (TMR) elements). An MTJ element includes at least three basic layers: a “free layer,” a tunneling barrier layer, and a “pinned layer.” The free layer and the pinned layer are ferromagnetic layers, the tunneling barrier layer is a thin insulator layer located between the free layer and the pinned layer. In the free layer, the magnetization direction is free to rotate; the magnetization of the pinned layer is not. An antiferromagnetic layer may be used to fix, or pin, the magnetization of the pinned layer in a particular direction. A bit is written to the element by changing the magnetization direction of one of the ferromagnetic plates of the magnetic element. Depending upon the orientations of the magnetic moments of the free layer and the pinned layer, the resistance of the MTJ element will change. Thus, the bit may be read by determining the resistance of the magnetic element. When the magnetization of the free layer and the pinned layer are parallel and the magnetic moments have the same polarity, the resistance of the MTJ element is low. Typically, this is designated a “0.” When the magnetization of the free layer and the pinned layer are antiparallel (i.e. the magnetic moments have the opposite polarity), the resistance of the MTJ is high. Typically, this is designated a “1.” 
     Spin torque transfer (STT) (also known as spin transfer switching or spin-transfer effect) is one technique for writing to memory elements. STT was developed as an alternative to using an external magnetic field to switch the direction of a free layer in the magnetic element. STT is based upon the idea that when a spin-polarized current (most of the electrons of the current have spins aligned in the same direction) is applied to a “free” ferromagnetic layer, the electrons may get repolarized on account of the orientation of the magnetic moments of the “free layer.” The repolarizing of the electrons leads to the free layer experiencing a torque associated with the change in the angular momentum of the electrons as they are repolarized. As a result, if the current density is high enough, this torque has enough energy to switch the direction of the magnetization of the free layer. The advantages of using STT for writing to magnetic elements are known in the art and include smaller bit size, lower number of process steps as compared with other writing techniques, scalability for large arrays, and lower writing current requirement. However, there are also disadvantages to using STT for writing to magnetic elements, as the current density required to switch the direction of magnetization in a free layer in the magnetic element is quite large. The critical current density required to switch the layer is denoted as “Jc.” In a conventional embodiment, Jc may be greater than 1E10 6  A/cm 2 . 
     As such, an improved magnetic element architecture allowing the use of STT is desired. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. 
         FIG. 1  is a cross-section illustrating an embodiment of a magnetic tunnel junction (MTJ) element. 
         FIG. 2  is a cross-section illustrating an embodiment of a magnetic element including a MTJ and an electrode. 
         FIG. 3  is a cross-section illustrating an alternative embodiment of a magnetic element. 
         FIGS. 4   a ,  4   b , and  4   c  are cross-sections of magnetic elements illustrating three embodiments of coupling an MTJ element and an electrode. 
         FIG. 5  is a flowchart illustrating an embodiment of a method of programming a magnetic element. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure relates generally to MRAM and more particularly, to a spin torque transfer magnetic element. It is understood, however, that specific embodiments are provided as examples to teach the broader inventive concept, and one of ordinary skill in the art can easily apply the teaching of the present disclosure to other methods or apparatus. In addition, it is understood that the methods and apparatus discussed in the present disclosure include some conventional structures and/or processes. Since these structures and processes are well known in the art, they will only be discussed in a general level of detail. Furthermore, reference numbers are repeated throughout the drawings for sake of convenience and example, and such repetition does not indicate any required combination of features or steps throughout the drawings. Moreover, the formation of a first feature over and on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact. 
     Referring to  FIG. 1 , illustrated is an embodiment of a magnetic element  100 . The magnetic element  100  includes a pinned layer  102  (also known as a reference layer), a barrier layer  104  (also known as tunneling barrier), and a free layer  106  (also known as a storage layer). The magnetic element  100  is a magnetic tunnel junction (MTJ) element as it has an insulator (the barrier layer  104 ) sandwiched between a free magnetic element (the free layer  106 ) and a fixed magnetic element (the pinned layer  102 ). The magnetic element  100  architecture allows the magnetization of the free layer to be switched using spin-torque transfer (STT). The following description of STT applied to the magnetic element  100  (as well as the general description included above) is based upon the current state of the art for reference only and not intended to be limiting the scope of the current disclosure. A current perpendicular to plane (CPP) configuration is described. 
     The magnetic moments of the free layer  106  are assumed initially antiparallel to the pinned layer  102 . Current, illustrated as arrow  110   b , can be supplied from the free layer  106  toward the pinned layer  102  to switch the magnetization of the free layer  106  to be parallel to the magnetization of the pinned layer  102 . When current is driven from the free layer  106  to the pinned layer  102  (i.e. in the direction of arrow  110   b ), conduction electrons travel from the pinned layer  102  to the free layer  106 . The majority electrons traveling from the pinned layer  102  have their spins polarized in the same direction as the magnetic moments of the pinned layer  102 . These electrons interact with the magnetic moments of the free layer  106  near the interface between the free layer  106  and the barrier layer  104 . Because of this interaction, the electrons transfer their spin angular momentum to the free layer  106 . This spin angular momentum is anti-parallel to the magnetization of the free layer  106 . If sufficient angular momentum is transferred by the electrons, the magnetization of the free layer  106  can be switched to be parallel to the magnetization of the pinned layer  102 . 
     Alternatively, current can be supplied from the opposite direction, illustrated as arrow  110   a , from the pinned layer  102  to the free layer  106 . Current from the direction of arrow  110   a  switches the magnetization of the free layer  106  to be antiparallel to the magnetization of the pinned layer  102 . The magnetization of the free layer  106  is assumed parallel to the pinned layer  102  prior to applying the current. When the current is driven from the pinned layer  102  to the free layer  106 , (i.e. in the direction of arrow  110   a ), conduction electrons travel in the opposite direction. The majority electrons have their spins polarized in the direction of the magnetization of the free layer  106  (i.e. same direction as the pinned layer  102 ). These majority electrons are transmitted through the pinned layer  102 . However, the minority electrons, which have spins polarized antiparallel to the magnetization of the free layer  106  and the pinned layer  102 , will be reflected from the pinned layer  102  and travel back to the free layer  106 . The minority electrons reflected interact with the magnetic moments of the free layer  106  and transfer a portion of their spin angular momentum to the free layer  106 . If sufficient angular momentum is transferred, the magnetization of the free layer  106  can be switched to be antiparallel to the magnetization of the pinned layer  102 . 
     Thus, the barrier layer  104  is thin enough to allow the tunneling of electrons through it. The barrier layer  104  has a nonmagnetic composition and can be formed from any suitable material that may function as an electrical insulator. In an embodiment, the barrier layer  104  includes alumina. In an alternative embodiment, the barrier layer  104  includes MgO. Examples of other dielectric materials that may be included in the barrier layer  104  include oxides or nitrides of Al, Mg, Si, Hf, Sr, or Ti such as, SiO x , SiN x , SiO x N y , AlO x , TO x , TiO x , AlN x , and/or combinations thereof. The barrier layer  104  may be formed by conventional processes such as, photolithography, chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), physical vapor deposition (PVD), electro-chemical deposition, molecular manipulation, oxidation, etching, chemical mechanical polishing, and/or other processes known in the art. The barrier layer  104  may electrically insulate the pinned layer  102  from the free layer  106  independently, or in conjunction with other layers (not illustrated) interposing the pinned layer  102  and the free layer  106 . 
     The pinned layer  102  and the free layer  106  are ferromagnetic layers. The pinned layer  102  and the free layer  106  may include Co, Fe, Ni, Mn, B, and/or their alloys, including for example, NiFe, NiFe, CoFe, CoFeB, or compounds thereof, including other ferromagnetic materials. The pinned layer  102  and/or the free layer  106  may be formed by conventional processes such as, photolithography, chemical vapor deposition (CVD), physical vapor deposition (PVD), electro-chemical deposition, molecular manipulation, etching, chemical mechanical polish, and/or other processes. The pinned layer  102  and the free layer  106  are illustrated in  FIG. 1  as single layers; however, as known in the art, either layer may be synthetic. 
     Referring now to  FIG. 2 , a magnetic element  200  is illustrated. The magnetic element  200  may be included in an MRAM device comprising an array of cells. The magnetic element  200  may be programmed using spin torque transfer (STT). The magnetic element  200  includes an MTJ element  202  and an electrode  204 . The electrode  204  is a spin-polarizing electrode. The MTJ element  202  is substantially similar to the magnetic element  100  and may include layers having substantially similar compositions and fabrication methods as the magnetic element  100 , described above with reference to  FIG. 1 . 
     The MTJ element  202  includes a free layer  202   a , a barrier layer  202   b , and a pinned layer  202   c . The free layer  202   a  is substantially similar to the free layer  106 , described above with reference to  FIG. 1 . The barrier layer  202   b  is substantially similar to the barrier layer  104 , also described above with reference to  FIG. 1 . The free layer  202   c  is substantially similar to the free layer  102 , also described above with reference to  FIG. 1 . The pinned layer  202   c  and the free layer  202   a  are illustrated as single ferromagnetic layers. However, as known in the art, any portion of the layers  202   a  and  202   c  may be synthetic. The MTJ element  202  may include or may be coupled to additional layers such as additional pinned layers, spacer layers, antiferromagnetic layers (or pinning layers), seed layers, capping layers, and/or other layers known in the art. One or more layers may be synthetic. In an embodiment, an antiferromagnetic layer is coupled to the pinned layer  202   c . The antiferromagnetic layer can pin the magnetization of the adjacent magnetic layer by exchanging coupling. Therefore, the antiferromagnetic layer can set, or “pin” the direction of magnetization of the pinned layer  202   c.    
     The electrode  204  includes a pinning layer  204   a , a pinned layer  204   b , and a non-magnetic, conductive layer  204   c . The conductive layer  240   c  interposes the pinned layer  204   b  and the free layer  202   a  of the MTJ element  202 . The conductive layer  204   c  may prevent electrical coupling and/or magnetic coupling (isolates magnetization) between the pinned layer  204   b  and the free layer  202   a . As such, the conductive layer  204   c  may be an “insulator” layer between the pinned layer  204   b  and the free layer  202   a . In an embodiment, the conductive layer  204   c  comprises Ta and/or TaN. Examples of other materials that may be included in the non-magnetic, conductive layer  204   c  include Ti, TiN, W, WN, Pt, metal silicides, metal nitrides, and/or conductive oxides. Examples of metal silicides include nickel silicide, cobalt silicide, tungsten silicide, tantalum silicide, titanium silicide, platinum silicide, erbium silicide, palladium silicide, and/or combinations thereof. Examples of a conductive oxide include NbO, ZnO, and/or combinations thereof. The thickness of the conductive layer  204   c  and the composition of the layer  204   c  should be optimized such that the magnetization of the free layer is increased and a lower Jc of the magnetic element  200  is provided. The conductive layer  204   c  may have a thickness no greater than approximately 600 A. In an embodiment, the thickness of the conductive layer  204   c  is approximately 500 A. The conductive layer  204   c  may be formed using conventional processes such as, photolithography, deposition, annealing, oxidation, etching, chemical mechanical polish, and/or other processes known in the art. 
     The pinned layer  204   b  is a ferromagnetic layer similar to the pinned layer  102 , described above with reference to  FIG. 1 . The pinned layer  204   b  may include Co, Fe, Ni, Mn and/or their alloys, including for example, NiFe, NiFe, CoFe, or compounds thereof including other ferromagnetic materials. The pinned layer  104   b  may be formed by conventional processes such as, photolithography, chemical vapor deposition (CVD), physical vapor deposition (PVD), electro-chemical deposition, molecular manipulation, etching, and/or other processes known in the art. 
     The pinning layer  204   a  is coupled to the pinned layer  204   b . The pinning layer  204   a  is an antiferromagnetic layer. In an embodiment, the pinning layer  204   a  includes PtMn. Examples of other antiferromagnetic materials that may be included in the pinning layer  204   a  include NiMn, PdMn, and IrMn. The pinning layer  204   a  sets or “pins” the direction of magnetization of the pinned layer  204   b . The pinning layer  204   a  may be formed by conventional processes such as, photolithography, chemical vapor deposition (CVD), physical vapor deposition (PVD), electro-chemical deposition, molecular manipulation, etching, and/or other processes known in the art. 
     In the illustrated embodiment, the electrode  204  is coupled to the MTJ element  202  creating an interface area  206 . The interface area  206  is the area of physical contact between (or the area of mating of, or the area of direct coupling of, or contact area) the electrode  204  and the MTJ element  202 . In the illustrated embodiment, the interface area  206  includes the area of contact between the conductive layer  204   c  of the electrode  204  and the free layer  202   a  of the MTJ element  202 . In other embodiments, it is possible that the interface area  206  include an area of contact between other layers of an electrode and an MTJ element. 
     The electrode  204  includes a surface, hereinafter described as a coupling surface. At least a portion of the coupling surface of the electrode  204  is physically coupled to the MTJ element  204 . The coupling surface of the electrode  204  has a surface area S 2 . In the illustrated embodiment, the coupling surface of the electrode  204  is a surface of the conductive layer  204   c . The MTJ element  202  also includes a surface, hereinafter described as a coupling surface. At least a portion of the coupling surface of the MTJ element  202  is physically coupled to the electrode  204 . The coupling surface of the MTJ element  202  has a surface area S 1 . In the illustrated embodiment, the coupling surface of the MTJ element  202  is a surface of the free layer  202   a.    
     In the illustrated embodiment, the interface area  206  is substantially equal to the surface area S 2  of the electrode  204 . The electrode  204  is coupled to the MTJ element  202  leaving an area d 1  and an area d 2  of the surface area S 1  of the MTJ element  202  without direct physical coupling with the electrode  204 . In an embodiment, the area d 1  may be approximately equal to the area d 2 . In an alternative embodiment, the area d 1  may be greater than or less than the area d 2  as the electrode  204  is asymmetrically coupled to the coupling surface of the MTJ element  202 . In an embodiment, the area d 1  and/or the area d 2  may be equal to zero. Further embodiments of the coupling of an electrode and an MTJ element are described in more detail below in reference to  FIGS. 4   a ,  4   b , and  4   c.    
     The magnetic element  200  is configured such that it may use spin torque transfer to program the element. The electrode  204  is electrically coupled such that a current is provided through the electrode  204  to the MTJ element  202 . The current through the electrode  204  becomes spin-polarized in the orientation of the pinned layer  204   b . The current provided through the electrode  204  may be of sufficient current density to force the magnetic moments of the free layer  202   a  to rotate at and near the interface area  206 . As the magnetic moments of the free layer  202   a  are coupled, when the magnetic moments at and near the interface area  206  begin to rotate, substantially all the magnetic moments of the layer will rotate. The current density of the provided current may be higher in the electrode  204  than the MTJ element  202  as the MTJ element  202  is larger than the electrode  204 . As the current only has to rotate the magnetic moments at the interface area  206 , as opposed to for example, the area S 1 , the current required to switch the free layer  202   a , Jc, may be decreased from conventional magnetic elements. 
     Referring now to  FIG. 3 , illustrated is cross-section of a magnetic element  300 . The magnetic element  300  may be included in a cell of an MRAM device. The magnetic element  300  is configured such that it may be programmed using spin torque transfer (STT). The magnetic element  300  may be formed on a substrate such as a semiconductor substrate including for example, silicon, germanium, and/or a compound semiconductor material. The magnetic element  300  includes a first interconnect  302  and a second interconnect  318 . The interconnects  302  and  318  may be formed of material suitable of conducting electricity, such as Al, Cu, Au, Ag, Ta, and/or combinations thereof. The interconnect  302  is operable to supply a current to the magnetic element  300 . In an embodiment, the interconnect  318  and/or  302  may include a barrier layer. Examples of barrier layer materials include Ti, Ta, TiN, TaN, WN, and SiC. 
     An electrode is coupled to the interconnect  302 ; the electrode including a pinning layer  304 , a pinned layer  306 , and a non-magnetic, conductive layer  308 . The pinning layer  304 , the pinned layer  306 , and the conductive layer  308  comprise a spin-polarizing electrode, substantially similar to electrode  204 , described above with reference to  FIG. 2 . The electrode may be fabricated using conventional semiconductor processing such as photolithography, etching, deposition, and other processes known in the art. For example, in an embodiment, a via is etched providing contact to the stack of films comprising the magnetic tunnel junction, described below. The width of the etched via is smaller than the width of the magnetic tunnel junction in order to provide higher current density through the via. The non-magnetic conductive layer  308 , the pinned layer  306 , and the pinning layer  304  are successively deposited/grown in the etched via. 
     A magnetic tunnel junction (MTJ) element is coupled to the electrode. The illustrated MTJ element includes a free layer  310 , a barrier layer  312 , a synthetic pinned layer including pinned layer  314   a , spacer layer  314   b , and pinned layer  314   c , and a pinning layer  316 . The pinning layer  316  may include one or more antiferromagnetic layers. In an embodiment, the antiferromagnetic layer may be composed of PtMn. Examples of other antiferromagnetic materials that may be included in the antiferromagnetic layer include NiMn, PdMn, IrMn, and/or combinations thereof. In an embodiment, a seed layer may be included under the antiferromagnetic layer 
     The synthetic pinned layer  314  includes two ferromagnetic layers  314   a  and  314   c  separated by the spacer layer  314   b . The ferromagnetic layers  314   a  and  314   c  may include Co, Fe, Ni, and/or their ferromagnetic alloys such as NiFe, CoFe or CoNiFe. The layers may also comprise half metallic ferromagnets such as, CrO 2 , NiMnSb, and/or PtMnSb. The spacer layer  314   b  includes a non-magnetic conductive material. In an embodiment, the spacer layer comprises Ru. Other examples of material that may be included in the spacer layer  314   b  include Ir and Re. The thickness of the spacer layer is such that the ferromagnetic layers  314   a  and  314   c  are antiferromagnetically coupled. 
     Adjacent the synthetic pinned layer  314  is the barrier layer  312 . The barrier layer  312  is substantially similar to the barrier layer  202   b  described above with reference to  FIG. 2 . The barrier layer  314  is sandwiched between the synthetic pinned layer  314  and the free layer  310 . The free layer  310  is substantially similar to the free layer  202   a  described above with reference to  FIG. 2 . 
       FIG. 3  also illustrates one embodiment of the magnetization of the layers of the magnetic element  300  (illustrated as arrows in each layer). The pinning layers  304  and  316  have magnetic moments in both directions in order to pin the adjacent layers as described above. The direction of the free layer  310  magnetization may be switched, including by the use of STT. The direction of magnetization of the pinned layer  306  is parallel to that of the pinned layer  314   c  (arbitrarily illustrated by an arrow pointing to the left). The pinned layer  314   a  has a magnetization that is opposite the magnetization of the pinned layer  306  and  314   c  (arbitrarily illustrated by an arrow pointing to the right). In an embodiment, the pinned layer  306  is subjected to magnetic annealing process to set the direction of the magnetization of the pinned layer  306 . In the magnetic annealing process, the heating and slow cooling of the pinned layer  306  in the presence of a magnetic field can create an easy axis of magnetization parallel to the applied magnetic field. 
     The magnetic element  300  and/or the magnetic element  200  may include other layers and/or the illustrated layers may be removed. For example, additional seed layers or capping layers may be present in the magnetic elements  300  and  200  that are not illustrated. As a further example, the disclosed coupling of an electrode and magnetic element may be combined with other magnetic architectures, such as dual spin filter (DSF) architectures. In addition, the disclosed coupling of an electrode and magnetic element may include architectures other than MTJ such as, giant magnetoresistance (GMR) magnetic elements. 
     Referring now to  FIGS. 4   a ,  4   b , and  4   c , a plurality of memory elements are illustrated. The memory elements  400 ,  410 , and  420  illustrate example architectures of the coupling of an electrode and a magnetic element. The figures are examples only and not intended to be limiting. The memory element  400  includes a magnetic element  402  and an electrode  404 ; the memory element  410  includes a magnetic element  412  and an electrode  414 ; the memory element  420  includes a magnetic element  422  and an electrode  424 . The magnetic elements  402 ,  412 , and/or  422  may be substantially similar to the MTJ element  202  and/or the MTJ element of the magnetic element  300 , described above with reference to  FIG. 2  and  FIG. 3  respectively. The electrodes  404 ,  414 , and/or  424  may be substantially similar to the electrode  204  and/or the electrode of magnetic element  300 , described above with reference to  FIG. 2  and  FIG. 3  respectively. The magnetic elements  402 ,  412 , and  422  each include a surface, hereinafter described as a coupling surface, a portion of which is physically coupled (or directly coupled, mated to, providing physical contact) to the electrodes  404 ,  414 , and  424  respectively. The electrodes  404 ,  414 , and  424  each include a surface, hereinafter described as a coupling surface, a portion of which is physically coupled to the magnetic elements  402 ,  412 , and  422  respectively. 
       FIG. 4   a  illustrates the electrode  404  coupled to the magnetic element  402  such that an interface area  406  is formed. More specifically, a coupling surface of the magnetic element  402  is mated to a coupling surface of the electrode  404  such that the interface area  406  is formed. The coupling surface of the electrode  404  has a surface area of Wele. The coupling surface of the magnetic element  402  has a surface area of Wmtj. In the illustrated embodiment, the interface area  406  includes the surface area Wele. The surface area Wmtj of the coupling surface of the magnetic element  402  includes areas x 1  and x 2  that are not physically coupled to the electrode  404 . The areas x 1  and x 2  may be equal to one another, different from one another, and/or equal to zero in various embodiments. 
       FIG. 4   b  illustrates a coupling of the magnetic element  412  and the electrode  414  wherein the electrode  414  is coupled asymmetrically with the magnetic element  412 . The magnetic element  412  includes a surface area W 2   mtj  that is the surface area of a coupling surface of the magnetic element  412 . The electrode  414  includes a surface area W 2   ele  that is the surface area of a coupling surface of the electrode  414 . The coupling surface of the magnetic element  412  is mated to the coupling surface of the electrode  414  such that an interface area  416  is formed. The interface area  416  is less than the surface area W 2   ele  of the coupling surface of the electrode  414  as a portion of the surface area W 2   ele  is not physically coupled to the magnetic element  412 , shown as the area outside of area y 1 . The interface area  416  is less than the surface area W 2   mtj  of the magnetic element  412 . 
       FIG. 4   c  illustrates a coupling of the magnetic element  422  and the electrode  424 . The electrode  424  is a tapered electrode having a first surface with a surface area W 3   ele  and a second surface with a surface area W 4   ele  that is parallel the first surface. The surface area W 4   ele  is smaller than the surface area W 3   ele . The surface area W 4   ele  is also the surface area of the coupling surface of the electrode  424 . The coupling surface of the magnetic element  422  is mated to the coupling surface of the electrode  424  such that an interface area  426  is formed. The interface area  426  is approximately equal to the surface area W 4   ele  of the electrode  424 . In an alternative embodiment, the interface area  426  may be smaller than the surface area W 4   ele , such as if the electrode  424  is asymmetrically coupled as illustrated in  FIG. 4   b . The interface area  426  is less than the coupling surface area W 3   mtj  of the magnetic element  422  as a portion of the surface area W 3   mtj  is not physically coupled to the electrode  424 , shown as areas z 1  and z 2 . The areas z 1  and z 2  may be equal to one another, different from one another, and/or equal to zero in various embodiments. 
     Referring now to  FIG. 5 , an embodiment of a method  500  of programming a magnetic element is illustrated. The method  500  begins at step  502  where a magnetic element is provided. The magnetic element includes a magnetic tunnel junction (MTJ) element coupled to an electrode. The magnetic element provided may be the magnetic element  200 ,  300 ,  400 ,  410 , and/or  420 , described above with reference to  FIGS. 2 ,  3 ,  4   a ,  4   b , and  4   c  respectively. The magnetic element may be one element included in an array of elements in an MRAM device. The method  500  then proceeds to step  504  where a current is supplied to the electrode of the magnetic element. The method then proceeds to step  506  where the current is spin-polarized by the electrode. The electrode may include a pinning layer and a pinned layer to polarize the current. The electrode may also include a conductive layer that is coupled to the magnetic tunnel junction element. The method then continues to step  508  where the current, now spin-polarized, is supplied to the MTJ element. The current is supplied to the MTJ element through an interface area. The interface area includes the area of physical coupling, or mating, between a coupling surface of the electrode and a coupling surface of the MTJ element. The interface area has a smaller surface area than the coupling surface of the MTJ element. In an embodiment, the electrode is smaller in width than the MTJ element providing a higher current density in the electrode than the MTJ element. This provides a higher current density at the interface area than the remainder of the MTJ element. In step  510 , the current at the interface area has a current density greater than Jc, and as such, switches the magnetization of the free layer of the MTJ element using spin torque transfer. 
     The method  500  then proceeds to step  512  where the magnetic element is read. The magnetic element may be read by providing a read current to measure the resistance of the magnetic element. In an embodiment, the current (provided in step  504 ) switches the magnetization of a free layer to be parallel the magnetization of a pinned layer in the MTJ element in step  510  and the resistance measured is low. In an embodiment, the current (provided in step  504 ) switches the magnetization of a free layer to be antiparallel the magnetization of a pinned layer in the MTJ element in step  510  and the resistance measured is high. The resistance measured in step  512  may correspond to the data type stored by the magnetic element, for example, a low resistance may indicate a “0” was stored, a high resistance may indicate a “1” was stored. 
     Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without material departing from the novel teachings and advantages of this disclosure. 
     Thus, the present disclosure provides a magnetic memory element. The memory element includes a magnetic tunnel junction (MTJ) element and an electrode. The electrode includes a pinned layer, a pinning layer, and a non-magnetic conductive layer. 
     Also provided is a method of forming a magnetic memory element. The method provides a substrate. A magnetic tunnel junction (MTJ) element is formed on the substrate. An electrode is formed on the substrate coupled to the MTJ element. The electrode includes forming a pinning layer, a pinned layer, and a non-magnetic conductive layer. 
     Also provided is a method of programming a magnetic memory element. A memory element is provided. The memory element includes an electrode coupled to a magnetic tunnel junction (MTJ) element. The MTJ element includes a free layer. A current is supplied to the electrode. The electrode is used to spin-polarize the current. The spin-polarized current from the electrode is supplied to the MTJ element through an interface area between the electrode and the MTJ element. The current supplied is sufficient to switch the free layer&#39;s magnetization direction.