Patent Description:
The present disclosure relates to, among other things, magnetoresistive devices and methods for fabricating and/or using the disclosed magnetoresistive devices.

In one or more embodiments, the present disclosure relates to a magnetoresistive device having a magnetoresistive stack or structure (for example, part of a magnetoresistive memory device and/or magnetoresistive sensor/transducer device) and methods of manufacturing and operating the described magnetoresistive devices. In one embodiment, an exemplary magnetoresistive stack (for example, used in a magnetic tunnel junction (MTJ) magnetoresistive device) of the present disclosure includes one or more layers of magnetic or ferromagnetic material <CIT>, <CIT> and <CIT> provide examples of such devices in the prior art. <CIT> discloses a magnetoresistive device based on SOT switching where a free layer is disposed on a spin hall layer. Above the free layer, a barrier layer, a reference layer, a transition layer, a fixed layer, an antiferromagnetic insertion layer and a capping layer are sequentially disposed.

Briefly, a magnetoresistive stack used in a memory device (e.g., a magnetoresistive random access memory (MRAM)) of the present disclosure includes at least one non-magnetic layer (for example, at least one dielectric layer or a non-magnetic yet electrically conductive layer) disposed between a "fixed" magnetic region and a "free" magnetic region, each including one or more layers of ferromagnetic materials. Information is stored in the magnetoresistive memory stack by switching, programming, and/or controlling the direction of magnetization vectors in the magnetic layer(s) of the free magnetic region. The direction of the magnetization vectors of the free magnetic region may be switched and/or programmed (for example, through spin orbit torque (SOT) and/or spin transfer torque (STT)) by application of a write signal (e.g., one or more current pulses) adjacent to, or through, the magnetoresistive memory stack. In contrast, the magnetization vectors in the magnetic layers of a fixed magnetic region are magnetically fixed in a predetermined direction during application of the write signal. When the magnetization vectors of the free magnetic region adjacent to the non-magnetic layer are in the same direction as the magnetization vectors of the fixed magnetic region adjacent to the non-magnetic layer, the magnetoresistive memory stack has a first magnetic state. Conversely, when the magnetization vectors of the free magnetic region adjacent to the non-magnetic layer are opposite the direction of the magnetization vectors of the fixed magnetic region adjacent to the non-magnetic layer, the magnetoresistive memory stack has a second magnetic state. The magnetoresistive memory stack has different electrical resistances in the first and second magnetic states. For example, a resistance (e.g., electrical) of the second magnetic state may be relatively higher than a resistance of the first magnetic state. The magnetic state of the magnetoresistive memory stack is determined or read based on the resistance of the stack in response to a read current applied, for example, through the magnetoresistive stack.

As magnetic memory devices (e.g., MRAM) advance towards smaller process nodes to increase density, individual MTJ bit sizes must laterally shrink to accommodate tighter pitch and space between bits. However, as the size and/or aspect ratio of the MTJ bit decreases, so does its shape magnetic anisotropy. With the decrease in shape anisotropy, the energy barrier of the MTJ may decrease. As the energy barrier decreases, however, the data retention and/or thermal stability of the MTJ bit also may decrease. Typically, the decrease in energy barrier of the MTJ bit may be corrected by increasing the perpendicular anisotropy or magnetic moment of the free region by altering its composition/material/thickness. However, doing so also may raise the critical current (described in greater detail below) of the MTJ bit. MTJ bits with high critical currents undergo a greater amount of periodic damage and degeneration during write and/or reset operations and negatively impact MTJ device (i.e. MRAM) endurance.

The present disclosure relates to devices (e.g., devices including magnetoresistive structures and/or stacks) and methods for writing or otherwise switching the magnetic state of a magnetoresistive memory device via STT and/or SOT switching schemes. More particularly, the description that follows describes embodiments of MTJ geometries which integrate SOT and/or STT switching mechanics, individually or in combination, to provide improved switching efficiency, enabling the switching of a high energy barrier MTJ bit without the use of unnecessary high magnitudes of write current. The scope of the current disclosure, however, is defined by the attached claims, and not by any characteristics of the resulting devices or methods.

Embodiments of the present disclosure may be implemented in connection with aspects illustrated in the attached drawings. These drawings show different aspects of the present disclosure and, where appropriate, reference numerals illustrating like structures, components, materials, and/or elements in different figures are labeled similarly. It is understood that various combinations of the structures, components, and/or elements, other than those specifically shown, are contemplated and are within the scope of the present disclosure.

For simplicity and clarity of illustration, the figures depict the general structure and/or manner of construction of the various embodiments described herein. For ease of illustration, the figures depict the different layers/regions of the illustrated magnetoresistive stacks as having a uniform thickness and well-defined boundaries with straight edges. However, a person skilled in the art would recognize that, in reality, the different layers typically have a non-uniform thickness. And, at the interface between adjacent layers, the materials of these layers may alloy together, or migrate into one or the other material, making their boundaries ill-defined. Descriptions and details of well-known features (e.g., interconnects, etc.) and techniques may be omitted to avoid obscuring other features. Elements in the figures are not necessarily drawn to scale. The dimensions of some features may be exaggerated relative to other features to improve understanding of the exemplary embodiments. The drawings are simplifications provided to help illustrate the relative positioning of various regions/layers and describe various processing steps. One skilled in the art would appreciate that the regions are not necessarily drawn to scale and should not be viewed as representing proportional relationships between different regions/layers. Moreover, while certain regions/layers and features are illustrated with straight <NUM>-degree edges, in actuality or practice such regions/layers may be more "rounded", curved, and/or gradually sloping.

Further, one skilled in the art would understand that, although multiple layers with distinct interfaces are illustrated in the figures, in some cases, over time and/or exposure to high temperatures, materials of some of the layers may migrate into or interact with materials of other layers to present a more diffuse interface between these layers. It should be noted that, even if it is not specifically mentioned, aspects described with reference to one embodiment may also be applicable to, and may be used with, other embodiments.

Moreover, there are many embodiments described and illustrated herein. The present disclosure is neither limited to any single aspect nor embodiment thereof, nor to any combinations and/or permutations of such aspects and/or embodiments. Moreover, each aspect of the present disclosure, and/or embodiments thereof, may be employed alone or in combination with one or more of the other aspects of the present disclosure and/or embodiments thereof. For the sake of brevity, certain permutations and combinations are not discussed and/or illustrated separately herein. Notably, an embodiment or implementation described herein as "exemplary" is not to be construed as preferred or advantageous, for example, over other embodiments or implementations; rather, it is intended to reflect or indicate that the embodiment(s) is/are "example" embodiment(s). Further, even though the figures and this written disclosure appear to describe the magnetoresistive stacks of the disclosed magnetoresistive devices in a particular order of construction (e.g., from bottom to top), it is understood that the depicted magnetoresistive stacks may have a different order (e.g., the opposite order (i.e., from top to bottom)).

The invention is only limited by the appended claims. In the following, only the embodiments of <FIG> are embodiments of the present invention. The remaining embodiments serve as illustrative examples useful for understanding the invention that do not form part of the present invention.

Again, there are many embodiments described and illustrated herein. The present disclosure is neither limited to any single aspect nor embodiment thereof, nor to any combinations and/or permutations of such aspects and/or embodiments. Each of the aspects of the present disclosure, and/or embodiments thereof, may be employed alone or in combination with one or more of the other aspects of the present disclosure and/or embodiments thereof. For the sake of brevity, many of those combinations and permutations are not discussed separately herein.

It should be noted that all numeric values disclosed herein (including all disclosed thickness values, limits, and ranges) may have a variation of ±<NUM>% (unless a different variation is specified) from the disclosed numeric value. For example, a layer disclosed as being "t" units thick can vary in thickness from (t-<NUM>. 1t) to (t+<NUM>. Further, all relative terms such as "about," "substantially," "approximately," etc. are used to indicate a possible variation of ±<NUM>% (unless noted otherwise or another variation is specified). Moreover, in the claims, values, limits, and/or ranges of the thickness and atomic composition of, for example, the described layers/regions, mean the value, limit, and/or range ±<NUM>%.

It should be noted that the description set forth herein is merely illustrative in nature and is not intended to limit the embodiments of the subject matter, or the application and uses of such embodiments. Any implementation described herein as exemplary is not to be construed as preferred or advantageous over other implementations. Rather, the term "exemplary" is used in the sense of example or "illustrative," rather than "ideal. " The terms "comprise," "include," "have," "with," and any variations thereof are used synonymously to denote or describe a non-exclusive inclusion. As such, a device or a method that uses such terms does not include only those elements or steps, but may include other elements and steps not expressly listed or inherent to such device and method. Further, the terms "first," "second," and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. Similarly, terms of relative orientation, such as "top," "bottom," etc. are used with reference to the orientation of the structure illustrated in the figures being described. Moreover, the terms "a" and "an" herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.

It should further be noted that, although exemplary embodiments are described in the context of MTJ stacks/structures, the present inventions may also be implemented in connection with giant magnetoresistive (GMR) stacks/structures where a conductor (e.g., a layer of copper) is disposed between two ferromagnetic regions/layers/materials. Embodiments of the present disclosure may be employed in connection with other types of magnetoresistive stacks/structures where such stacks/structures include a fixed magnetic region. For the sake of brevity, the discussions and illustrations presented in this disclosure will not be repeated specifically in the context of GMR or other magnetoresistive stacks/structures (e.g., anisotropic magnetoresistive (AMR) devices), but the discussion and drawings described below are to be interpreted as being entirely applicable to GMR and other magnetoresistive stacks/structures (e.g., AMR-type devices).

In this disclosure, the term "region" may be used generally to refer to one or more layers. That is, a region (as used herein) may include a single layer (deposit, film, coating, etc.) of material or multiple layers of materials stacked one on top of another (i.e., a multi-layer structure). Further, although in the description below, the different regions and/or layers in the disclosed magnetoresistive devices may be referred to by specific names (e.g., bottom electrode, top electrode, fixed magnetic region, free magnetic region. ), this is only for ease of description and not intended as a functional description or relative location/orientation of the layer. Moreover, although the description below and the figures appear to depict a certain orientation of the layers relative to each other, those of ordinary skill in the art will understand that such descriptions and depictions are only exemplary. For example, though a free region of a magnetoresistive stack may be depicted as being "above" a spin-Hall (SH) material, in some aspects the entire depicted magnetoresistive structure may be flipped such that the free region is "below" the SH material.

In one exemplary embodiment, a magnetoresistive structure of a magnetoresistive device of the present disclosure may be implemented as a STT and/or SOT MRAM element. In such embodiments, the magnetoresistive structure may include an intermediate layer disposed (e.g., sandwiched) between two ferromagnetic regions to form an MTJ device or an MTJ-type device. Of the two ferromagnetic regions disposed on either side of the intermediate layer, one ferromagnetic region may be a fixed (or pinned) magnetic region, and the other ferromagnetic region may be a free magnetic region. The term free is intended to refer to ferromagnetic regions having a magnetic moment that may shift or move significantly in response to applied magnetic fields or spin-polarized currents used to switch the magnetic moment vector. Relatedly, the words fixed or "pinned" are used to refer to ferromagnetic regions having a magnetic moment vector that does not move substantially in response to such applied magnetic fields or spin-polarized currents. As is known in the art, an electrical resistance of the described magnetoresistive structure may change based on whether the magnetization direction (e.g., the direction of the magnetic moment) of the free region adjacent to the non-magnetic layer (e.g., a tunnel barrier) is in parallel alignment or in an antiparallel alignment with the magnetization direction (e.g., the direction of the magnetic moment) of the fixed region adjacent to the non-magnetic layer. Typically, if the two regions have the same magnetization alignment, the resulting relatively low resistance is considered as a digital "<NUM>," while if the alignment is antiparallel the resulting relatively higher resistance is considered to be a digital "<NUM>. " A memory device (e.g., an MRAM) may include multiple magnetoresistive structures/stacks, which may be referred to as memory cells or elements, arranged in an array of columns and rows. By measuring the current through each cell, the resistance of each cell, and thus the data stored in the memory array can be read.

In some embodiments, the free magnetic region and the fixed magnetic region may each include a plurality of the layer(s) of magnetic or ferromagnetic materials, For example, materials that include one or more of the ferromagnetic elements nickel (Ni), iron (Fe), and cobalt (Co), including, for example, alloys or engineered materials with one or more of the elements palladium (Pd), platinum (Pt), magnesium (Mg), manganese (Mn), and chromium (Cr), boron (B)) as well as one or more synthetic antiferromagnetic structures (SAF) or synthetic ferromagnetic structures (SyF) wherein one or more layers of magnetic materials layers may also include one or more non-magnetic materials layers (for example, ruthenium (Ru), copper (Cu), aluminum (Al), tantalum (Ta), titanium (Ti), niobium (Nb), vanadium (V), zirconium (Zr), iridium (Ir) and one or more alloys thereof, and in certain embodiments, tungsten (W) and molybdenum (Mo). An intermediate layer (e.g., a dielectric layer) may be, for example, one or more layers of aluminum oxide and/or magnesium oxide.

In a magnetoresistive device utilizing SOT switching mechanics, switching the magnetization of the free region of a magnetoresistive stack may be accomplished, or assisted, by driving a current pulse through a SH material proximate (e.g., in contact with or near) the free region. Examples of SH materials include, but are not limited to, platinum (Pt), beta-tungsten (β-W), tantalum (Ta), palladium (Pd), hafnium (Hf), gold (Au), alloys including gold (e.g., AuPt, AuCu, AuW), alloys including bismuth (Bi) and selenium (Se) (e.g., Bi<NUM>Se<NUM> or (BiSe)<NUM>Te<NUM>), alloys including copper (Cu) and one or more of platinum (Pt), bismuth (Bi), iridium (Ir), or lead (Pb) (e.g., CuPt alloys, CuBi alloys, CuIr alloys, CuPb alloys), alloys including silver (Ag) and bismuth (Bi) (e.g., AgBi alloys), alloys including manganese (Mn) and one or more of platinum (Pt), iridium (Ir), palladium (Pd), or iron (Fe) (e.g., PtMn alloys, IrMn alloys, PdMn alloys, FeMn alloys), or combinations thereof.

The mean current required to be passed through a free region in order to change its magnetic state may be referred to as the critical current (Ic). The critical current is indicative of the current required to "write" data in a magnetoresistive memory cell. Reducing the critical current is desirable so that, among other things, a smaller access transistor can be used for each memory cell and that a higher density, lower cost memory can be produced. A reduced critical current may also lead to greater longevity and/or durability of a magnetoresistive memory cell.

Embodiments described herein may utilize what may be referred to as spin current to switch or aid in switching the magnetic state of the free region in an MTJ or MTJ-like device. Current through an SH material adjacent to (and/or in contact with) the free region results in a spin torque acting on the free region due to the injection of a spin current into the free region from the spin-dependent scattering of electrons in the SH material. The polarity of the current through the SH material and the polarity of the SH material itself may determine the direction in which the spin current is imparted. The spin current is injected into the free region in a direction perpendicular to the boundary (or interface) where the free region and the SH material meet, and orthogonal to the direction of the current flow. The spin torque applied to the free region by the spin current impacts the magnetic state of the free region in a manner similar to spin-polarized tunneling current that flows through the MTJ in traditional STT magnetic tunnel junctions. As the function of STT magnetic tunnel junctions is well known in the art, it will not be further described here.

As with write currents in conventional STT MTJ devices, in devices using SOT switching mechanisms, the direction of torque applied by the spin current is dependent on the direction of the current flow in the SH material. In other words, the direction of current flow within the SH material proximate to the free region determines the direction of torque that is applied to the free region. Accordingly, the free region may be able to be switched between two stable states based on torque applied by current flowing in the proximate SH material in one direction or the other. In some embodiments, the free region may be able to be switched between two stable magnetic states based on the torque applied by a STT current flowing in either direction through the MTJ. The magnetic state of the free region may also be switching by the torque resulting from both an STT current by applying an electrical current through MTJ bit and the spin torque by a spin current injected from one or more SH materials by applying an electrical current through one or more SH materials.

In some embodiments, the torque applied by the spin current (i.e., SOT current) alone is used to switch the free region into a particular magnetic state, whereas in other embodiments, the spin current works as an "assist" to reduce the magnitude of an STT write current required to switch the magnetic state of the free region, where the STT write current travels through the entirety of the MTJ stack to produce a spin polarized tunneling current between the free region and fixed region. Reading of data stored by the MTJ stack is accomplished as in a conventional STT MTJ device. For example, a read current, having a magnitude less than that of the critical current of the MTJ stack, is applied to the MTJ stack to sense the resistance of the MTJ stack. As a person of ordinary skill in the art would recognize, there are many techniques that may be used to detect or sense the resistance of the MTJ stack. In some embodiments, the resistance sensed based on the read current can be compared with a reference resistance to determine the state of the free region. In some embodiments, a self-referenced read operation is performed where the resistance through the MTJ is sensed, then the MTJ is written (or reset) so that the free region is in a known state, then the resistance is sensed again and compared with the resistance originally sense. The original state of the free region can then be determined based on whether the resistance sense has changed based on the write or reset operation. In still other embodiments, a mid-point reference read operation may be performed.

For the sake of brevity, conventional techniques related to semiconductor processing may not be described in detail herein. The exemplary embodiments may be fabricated using known lithographic processes. The fabrication of integrated circuits, microelectronic devices, microelectric mechanical devices, microfluidic devices, and photonic devices involves the creation of several layers or regions (e.g., comprising one or more layers) of materials that interact in some fashion. One or more of these regions may be patterned so various regions of the layer have different electrical or other characteristics, which may be interconnected within the region or to other regions to create electrical components and circuits. These regions may be created by selectively introducing or removing various materials. The patterns that define such regions are often created by lithographic processes. For example, a layer of photoresist is applied onto a layer overlying a wafer substrate. A photo mask (containing clear and opaque areas) is used to selectively expose the photoresist by a form of radiation, such as ultraviolet light, electrons, or x-rays. Either the photoresist exposed to the radiation, or not exposed to the radiation, is removed by the application of the developer. An etch may then be employed/applied whereby the layer (or material) not protected by the remaining resist is patterned. Alternatively, an additive process can be used in which a structure is built up using the photoresist as a template.

As noted above, in one aspect, the described embodiments relate to, among other things, methods of manufacturing a magnetoresistive stack having one or more electrically conductive electrodes, vias, or conductors on either side of a magnetic material stack. As described in further detail below, the magnetic material stack may include many different regions of material, where some of these regions include magnetic materials, whereas others do not. In one embodiment, the methods of manufacturing include sequentially depositing, growing, sputtering, evaporating, and/or providing (which may be referred to collectively herein as "depositing") regions which after further processing (e.g., etching) form a magnetoresistive stack.

In some embodiments, the disclosed magnetoresistive stacks may be formed between a top electrode/via/line and a bottom electrode/via/line and which permit access to the stack by allowing for connectivity (e.g., electrical) to circuitry and other elements of the magnetoresistive device. Between the electrodes/vias/lines are multiple regions, including at least one fixed magnetic region (which may be referred to hereinafter as a fixed region) and at least one free magnetic region (which may be referred to hereinafter as a free region) with one or more intermediate layers (e.g., a dielectric layer) that forms a tunnel barrier between the fixed region and the free region. Each of the fixed region and the free region may include, among other things, a plurality of ferromagnetic layers. In some embodiments, the fixed region (e.g., fixed region <NUM> discussed below) may include a synthetic antiferromagnet (SAF). In some embodiments, a top electrode (and/or) bottom electrode may be eliminated and a bit line and/or SH material may be formed on top of the stack. Additionally, each magnetoresistive stack may be disposed proximate to an SH material. The SH material may be configured to carry current and impart spin current on the free region during write and reset operations. In one or more embodiments, one or more electrodes of a magnetoresistive stack may include an SH material. In other embodiments, a magnetoresistive stack may be formed between a top electrode and a bottom electrode and proximate to an SH material, the SH material being independently connected to a current source. In such embodiments, the magnetoresistive structure or device may be referred to as a three-terminal magnetoresistive device.

According to one or more embodiments, a magnetoresistive structure may include a reference layer, a transition layer, and/or a cap region. For example, a transition layer may facilitate, promote, or otherwise assist the formation of a reference layer above the intermediate layer (e.g., a dielectric layer) without deleterious affecting the properties of the reference layer or intermediate layer. Transition layer may include a non-ferromagnetic transition metal, such as, for example, tantalum (Ta), titanium (Ti), tungsten (W), molybdenum (Mo), or combinations and alloys thereof.

Reference layer may include one or more layers of material that, among other things, facilitate and improve the growth of one or more overlying regions (e.g., a fixed region including a SAF) during manufacture of magnetoresistive structure <NUM>. The reference layer may include, e.g., cobalt (Co), iron (Fe), and boron (B), such as a cobalt-iron-boron alloy (CoFeB), a cobalt-iron-boron-tantalum allow (CoFeBTa), a cobalt-iron-tantalum alloy (CoFeTa), or combinations thereof. In some embodiments, reference layer may include one or more alloys that include iron (Fe), cobalt (Co) or nickel (Ni), and other relatively electronegative elements (e.g., elements with an electronegativity greater than the electronegativity of iron (Fe)). For example, the reference layer may include one or more alloys, such as, for example, an alloy having the formula XY, where X is selected from a list comprising: cobalt (Co), iron (Fe), nickel (Ni), cobalt-iron (CoFe), iron-nickel (FeNi), and cobalt-nickel (CoNi), and Y is selected from a list comprising: silicon (Si), copper (Cu), rhenium (Re), tin (Sn), boron (B), molybdenum (Mo), ruthenium (Ru), palladium (Pd), osmium (Os), iridium (Ir), rhodium (Rh), platinum (Pt), tungsten (W), and carbon (C). Inclusion in the alloy of one or more elements, that have an electronegativity greater than the electronegativity of iron (Fe) (e.g., silicon (Si), copper (Cu), rhenium (Re), tin (Sn), boron (B), molybdenum (Mo), ruthenium (Ru), palladium (Pd), osmium (Os), iridium (Ir), rhodium (Rh), platinum (Pt), tungsten (W), carbon (C)).

Referring now to <FIG>, various magnetoresistive structures (e.g., the relative location and orientation of the free region, the intermediate layer, the fixed region, one or more SH materials, and/or one or more other layers or regions) are shown. The simplified illustrations in <FIG> do not necessarily show all regions and layers of an exemplary magnetoresistive structure, but instead are intended to illustrate the relative location and positioning of several exemplary regions. Further, although the regions depicted in <FIG> are rectangular in shape, this is for simplicity and clarity only. The magnetoresistive structures described herein may have a rectangular, trapezoidal, pyramidal, cylindrical, or other shape.

Still referring to <FIG>, a magnetoresistive structure <NUM> may include one or more regions or layers between a line, strip, or region of SH material <NUM> and a top electrode <NUM>. For example, referring to <FIG>, a free region <NUM>, may be disposed on and in contact with SH material <NUM>. An intermediate layer <NUM> may be disposed on and in contact with free region <NUM>. A fixed region <NUM> may be disposed on the other side of intermediate layer <NUM> from free region <NUM>. In some embodiments, fixed region <NUM> may be disposed on and in contact with intermediate layer <NUM>. The magnetoresistive structure <NUM>, may include one or more additional regions or layers, such as, for example, a cap region <NUM>. Cap region <NUM> may be disposed above and in contact with fixed region <NUM>. Top electrode <NUM> may be disposed above fixed region <NUM>, such as, for example, disposed above and in contact with cap region <NUM>.

Referring again to <FIG>, for read operations, current may pass from SH material <NUM>, through the magnetoresistive structure <NUM>, to top electrode <NUM>. For write and/or reset operations, current may pass along SH material <NUM>, imparting spin current to free region <NUM>. In addition, a write current may also be passed from SH material <NUM>, through the magnetoresistive structure <NUM>, to top electrode <NUM>, to assist in switching the magnetic state of free region <NUM>.

According to one or more embodiments, a magnetoresistive structure <NUM> may include one or more insertion layers adjacent to cap region <NUM> and/or transition layer <NUM> According to the invention, the magnetoresistive structure comprises at least two such insertion layers. Each of the one or more insertion layers includes one or more layers of antiferromagnetic (AFM) material such as platinum-manganese (PtMn) alloys, iridium-manganese (IrMn) alloys, iron-manganese (FeMn) alloys, chromium (Cr), and/or combinations thereof. In embodiments where a magnetoresistive structure <NUM> includes more than one insertion layer, the composition of one insertion layer may be the same as the composition of another insertion layer and/or the composition of one insertion layer may be different than at least one other insertion layer.

Referring to <FIG> that show examples not forming part of the present invention magnetoresistive structure <NUM> may include an insertion layer <NUM> disposed between reference layer <NUM> and top electrode <NUM>. For example, referring to <FIG>, magnetoresistive structure <NUM> may include an insertion layer <NUM> disposed between cap region <NUM> and top electrode <NUM>. In some embodiments, such as the embodiment shown in <FIG>, magnetoresistive structure <NUM> may include an insertion layer <NUM> disposed between fixed region <NUM> and cap region <NUM>. Referring to <FIG>, magnetoresistive structure <NUM> may include an insertion layer <NUM> disposed between transition layer <NUM> and fixed region <NUM>. In addition or alternatively, magnetoresistive structure <NUM> may include an insertion layer <NUM> disposed between reference layer <NUM> and transition layer <NUM>, as shown in <FIG>.

Insertion layer <NUM> may have a thickness less than or equal to approximately <NUM> nanometers (nm), such as for example, less than or equal to approximately <NUM>, less than or equal to approximately <NUM>, approximately <NUM> to approximately <NUM>, approximately <NUM> to approximately <NUM>, approximately <NUM> to approximately <NUM>, approximately <NUM> to approximately <NUM>, approximately <NUM>, approximately <NUM>, or any other suitable thickness that does not deleteriously affect the bidirectional transfer of current from SH material <NUM> to top electrode <NUM>.

Referring to <FIG>, a magnetoresistive structure <NUM> according to the invention includes a first insertion layer <NUM> and a second insertion layer <NUM>. As described above, the terms "first," "second," and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. First insertion layer <NUM> may have the same composition as second insertion layer <NUM>, or the insertion layers <NUM>, <NUM> may have different compositions. Second insertion layer <NUM> may have a similar thickness as first insertion layer <NUM>, described above. In some embodiments, second insertion layer <NUM> may have a thickness less than a thickness of first insertion layer <NUM>. In other embodiments, second insertion layer <NUM> may have a thickness greater than a thickness of first insertion layer <NUM>.

For example, referring to <FIG>, a magnetoresistive structure <NUM> may include a first insertion layer <NUM>, disposed between fixed region <NUM> and cap region <NUM>, and a second insertion layer <NUM>, disposed between cap region <NUM> and top electrode <NUM>. In some embodiments, such as the embodiment shown in <FIG>, a magnetoresistive structure <NUM> may include a first insertion layer <NUM>, disposed between transition layer <NUM> and fixed region <NUM>, and a second insertion layer <NUM>, disposed between cap region <NUM> and top electrode <NUM>. Referring to <FIG>, a magnetoresistive structure <NUM> may include a first insertion layer <NUM>, disposed between reference layer <NUM> and transition layer <NUM>, and a second insertion layer <NUM>, disposed between cap region <NUM> and top electrode <NUM>. In some embodiments, magnetoresistive structure <NUM> may include a first insertion layer <NUM>, disposed between transition layer <NUM> and fixed region <NUM>, and a second insertion layer <NUM>, disposed between fixed region <NUM> and cap region <NUM>, as shown in <FIG>. Referring to <FIG>, a magnetoresistive structure <NUM> may include a first insertion layer <NUM> disposed between reference layer <NUM> and transition layer <NUM>, and a second insertion layer <NUM> disposed between fixed region <NUM> and cap region <NUM>. In addition or alternatively, magnetoresistive structure <NUM> may include a first insertion layer <NUM> disposed between reference layer <NUM> and transition layer <NUM>, and a second insertion layer <NUM> disposed between transition layer <NUM> and fixed region <NUM>, as shown in <FIG>.

Referring to <FIG> that show further embodiments of the invention a magnetoresistive structure <NUM> may include a first insertion layer <NUM>, a second insertion layer <NUM>, and a third insertion layer <NUM>. First insertion layer <NUM> may have the same composition as second insertion layer <NUM> and third insertion layer <NUM>, or one or more insertion layers <NUM>, <NUM>, <NUM> may have a different composition than at least one other insertion layer <NUM>, <NUM>, <NUM>. Third insertion layer <NUM> may have a similar thickness as first insertion layer <NUM> or second insertion layer <NUM>, as described above. In some embodiments, third insertion layer <NUM> may have a thickness less than a thickness of first insertion layer <NUM> and/or second insertion layer <NUM>. In addition or alternatively, third insertion layer <NUM> may have a thickness greater than a thickness of first insertion layer <NUM> and/or second insertion layer <NUM>.

For example, referring to <FIG>, a magnetoresistive structure <NUM> may include a first insertion layer <NUM> disposed between transition layer <NUM> and fixed region <NUM>, a second insertion layer <NUM> disposed between fixed region <NUM> and cap region <NUM>, and a third insertion layer <NUM> disposed between cap region <NUM> and top electrode <NUM>. In another example, as shown in <FIG>, magnetoresistive structure <NUM> may include a first insertion layer <NUM> disposed between reference layer <NUM> and transition layer <NUM>, a second insertion layer <NUM> disposed between transition layer <NUM> and fixed region <NUM>, and a third insertion layer <NUM> disposed between cap region <NUM> and top electrode <NUM>. Referring to <FIG>, in some embodiments, magnetoresistive structure <NUM> may include a first insertion layer <NUM> disposed between reference layer <NUM> and transition layer <NUM>, a second insertion layer <NUM> disposed between fixed region <NUM> and cap region <NUM>, and a third insertion layer <NUM> disposed between cap region <NUM> and top electrode <NUM>. In some examples, magnetoresistive structure <NUM> may include a first insertion layer <NUM> disposed between reference layer <NUM> and transition layer <NUM>, a second insertion layer <NUM> disposed between transition layer <NUM> and fixed region <NUM>, and a third insertion layer <NUM> disposed between fixed region <NUM> and cap region <NUM>, as shown in <FIG>.

Referring to <FIG>, a magnetoresistive structure <NUM> according to the invention may include four insertion layers (e.g., first insertion layer <NUM>, second insertion layer <NUM>, third insertion layer <NUM>, and fourth insertion layer <NUM>). In some embodiments, fourth insertion layer <NUM> may have the same composition as first insertion layer <NUM>, second insertion layer <NUM>, and/or third insertion layer <NUM>. In addition or alternatively, one or more insertion layers <NUM>, <NUM>, <NUM>, <NUM> may have a different composition than at least one other insertion layer <NUM>, <NUM>, <NUM>, <NUM>. Fourth insertion layer <NUM> may have a similar thickness as first insertion layer <NUM>, second insertion layer <NUM>, or third insertion layer <NUM>, as described above. In some embodiments, fourth insertion layer <NUM> may have a thickness less than a thickness of first insertion layer <NUM>, second insertion layer <NUM>, and/or third insertion layer <NUM>. In addition or alternatively, fourth insertion layer <NUM> may have a thickness greater than a thickness of first insertion layer <NUM>, second insertion layer <NUM>, and/or third insertion layer <NUM>.

Still referring to <FIG>, magnetoresistive structure <NUM> may include a first insertion layer <NUM> disposed between reference layer <NUM> and transition layer <NUM>, a second insertion layer <NUM> disposed between transition layer <NUM> and fixed region <NUM>, a third insertion layer <NUM> disposed between fixed region <NUM> and cap region <NUM>, and a fourth insertion layer <NUM> disposed between cap region <NUM> and top electrode <NUM>.

Without being limited by theory, inclusion of one or more insertion layers <NUM>, <NUM>, <NUM>, <NUM> may induce a localized magnetic field. For example, after magnetoresistive structure <NUM> is formed, one or more subsequent processing steps (e.g., annealing) may be performed that induces a magnetic moment in one or more insertion layers <NUM>, <NUM>, <NUM>, <NUM>, thereby generating a localized magnetic field. The induced localized magnetic field may facilitate, improve, and/or maintain the transfer of spin current from SH material <NUM> to free region <NUM>.

For example, referring to <FIG>, a magnetoresistive structure <NUM> may include an insertion layer <NUM>. The magnetic moment of the insertion layer <NUM>, represented by arrow <NUM>, may induce a localized stray magnetic field <NUM>. The localized stray magnetic field <NUM> may have a magnitude of approximately <NUM> oersted (Oe) to approximately <NUM> Oe. As current (represented by arrow <NUM>) passes through SH material <NUM>, spin current (represented by arrows <NUM>) is imparted from SH material <NUM> to free region <NUM>. When the magnetic moment of one or more insertion layers (e.g., insertion layer <NUM>) is parallel or anti-parallel to the current <NUM> passed through SH material <NUM>, the induced localized stray magnetic field <NUM> may improve the transfer of spin current <NUM> from SH material <NUM> to free region <NUM>.

<FIG> shows a cross section, taken at line 17B-17B, of the magnetoresistive structure <NUM> shown in <FIG>. As can be seen in <FIG>, one or more insertion layers (e.g., insertion layer <NUM>) may be ovular, elongated, elliptical, or other non-rectangular shape. One or more other layers and/or regions of magnetoresistive structure <NUM> (e.g., free region <NUM>, intermediate layer <NUM>, reference layer <NUM>, transition layer <NUM>, fixed region <NUM>, cap region <NUM>) may be ovular, elongated, elliptical, or other non-rectangular shape. Magnetoresistive structures <NUM> that include one or more layers and/or regions with a non-rectangular shape, may have a shape anisotropy that contributes to the magnetic moment one or more magnetic or anti-ferromagnetic layers of the magnetoresistive structure <NUM>.

After one or more layers and/or regions of a magnetoresistive structure <NUM> are formed, further processing steps may be undertaken to insure that the magnetoresistive device structure has the desired magnetic properties. For example, the further processing steps may include an annealing step that fixes the magnetic properties of one or more insertion layers <NUM>, <NUM>, <NUM>, <NUM> and/or one or more magnetic layers (e.g., magnetic layers of fixed region <NUM>). During annealing, an external magnetic field may be applied. The magnitude and/or direction of the localized stray magnetic field <NUM>, induced by one or more insertion layers <NUM>, <NUM>, <NUM>, <NUM>, may be at least partially dependent on the angle of magnetic field applied during annealing. During annealing, a magnetic field may be applied in a direction at that is approximately <NUM>° to approximately <NUM>° (e.g., approximately <NUM>° to <NUM>°, or approximately <NUM>°) incident, in the x-y plane, to a line of SH material <NUM> (e.g., the direction of current traveling through SH material <NUM>). Other suitable incident angles may be used, such that the resulting insertion layer <NUM>, <NUM>, <NUM>, <NUM> has a magnetic moment that is parallel or anti-parallel to the direction current flows through SH material <NUM>.

As described previously, one or more devices or systems may include a series of magnetoresistive structures <NUM>, positioned along a linear SH material <NUM>. The layers and regions of each magnetoresistive structure <NUM> above the connecting SH material <NUM> may be referred to as a stack <NUM>. For example, referring to the magnetoresistive structure <NUM> shown in <FIG>, the stack <NUM> includes free region <NUM>, intermediate layer <NUM>, reference layer <NUM>, transition layer <NUM>, fixed region <NUM>, cap region <NUM>, and top electrode <NUM>. In other embodiments, stack <NUM> may include one or more insertion layers <NUM>, <NUM>, <NUM>, <NUM>. A segment of SH material <NUM> may be connected to a series of stacks <NUM> arranged in a line or other array.

In the methods described above, an external magnetic field is required during annealing to break the symmetry of magnetoresistive structure <NUM>, and induce a magnetic moment in one or more layers and/or regions of stack <NUM>. Additionally or in the alternative, one or more layers and/or regions of magnetoresistive structure <NUM> may be etched in a manner to create an asymmetric magnetoresistive structure <NUM>, imparting the desired magnetic properties to one or more layers and/or regions of stack <NUM>. In <FIG>, the stack <NUM> shown is similar to the stack <NUM> shown in <FIG>. However, this is only for ease of illustration, the embodiment methods may be used with any stack <NUM> or magnetoresistive structure <NUM> described herein.

Referring to <FIG>, similar to <FIG> and <FIG>, each magnetoresistive structure <NUM> is drawn such that SH material <NUM> lies in an x-y plane and each layer and/or region of each stack <NUM> lies in a generally parallel x-y plane, displaced along a z-axis. This orientation of each region, layer, and structure, shown in <FIG> is for clarity of description only. Other configurations, placements, and orientations of layers and/or regions are contemplated.

An exemplary method of manufacturing a magnetoresistive stack with SOT switching (e.g., a magnetoresistive stack including one of the geometries discussed above) will now be discussed with reference to <FIG>. As previously stated, commonly performed conventional techniques related to semiconductor processing may not be specifically described herein. Rather, the description herein is intended to highlight aspects of example methods of manufacturing a magnetoresistive structure described herein.

<FIG> shows a magnetoresistive structure, during a manufacturing process, according to one or more embodiments of the present disclosure. For example, in at least one embodiment, <FIG> shows a magnetoresistive structure after SH material <NUM>, free region <NUM>, intermediate layer <NUM>, reference layer <NUM>, transition layer <NUM>, fixed region <NUM>, cap region <NUM>, and top electrode <NUM> have been formed. As described above, each layer or region may lie in an x-y plane, displaced from each neighboring layer or region along a z-axis.

In some embodiments, after SH material <NUM>, free region <NUM>, intermediate layer <NUM>, reference layer <NUM>, transition layer <NUM>, fixed region <NUM>, cap region <NUM>, and top electrode <NUM> have been formed, at least a portion of top electrode <NUM>, cap region <NUM>, fixed region <NUM>, transition layer <NUM>, reference layer <NUM>, and/or intermediate layer <NUM> may be removed (e.g., etched). For example, referring to <FIG>, after at least a portion of top electrode <NUM>, cap region <NUM>, fixed region <NUM>, transition layer <NUM>, reference layer <NUM>, and/or intermediate layer <NUM> are removed, the remaining portions of reference layer <NUM>, transition layer <NUM>, fixed region <NUM>, cap region <NUM>, and top electrode <NUM> may have a diameter (e.g., a width along the x and/or y-axis) less than a diameter of free region <NUM>. In some embodiments, portions of the reference layer <NUM> are removed up to the edge of intermediate layer <NUM>. In other embodiments, these portions of reference layer <NUM> may be "over-etched. " In other words, a portion of intermediate layer <NUM> may be removed with the portions of top electrode <NUM>, cap region <NUM>, fixed region <NUM>, transition layer <NUM>, reference layer <NUM>, and/or intermediate layer <NUM>.

In some embodiments, after at least a portion of top electrode <NUM>, cap region <NUM>, fixed region <NUM>, transition layer <NUM>, reference layer <NUM>, and/or intermediate layer <NUM> are removed, one or more oxides (e.g., auxiliary oxide, silica, etc.) or nitrides (e.g. SixNy) may be applied to the stack (e.g., the etched magnetoresistive stack) by, for example, physical vapor deposition (PVD), chemical vapor deposition (CVD), other thin film fabrication processes, and/or other technique known in the art. <FIG> shows an etched magnetoresistive structure that has been coated with auxiliary oxide (i.e., an oxide-coated magnetoresistive stack), according to one or more embodiments.

Still referring to <FIG>, in one or more embodiments, an oxide region <NUM> is formed over intermediate layer <NUM>, reference layer <NUM>, transition layer <NUM>, fixed region <NUM>, cap region <NUM>, and/or top electrode <NUM>. As used herein, oxide region <NUM> may refer to a region that includes oxides (e.g., auxiliary oxide, silica, etc.) and/or nitrides (e.g., SixNy). In some embodiments, the oxide-coated magnetoresistive stack may include one or more oxide regions <NUM> disposed above and in contact with intermediate layer <NUM>. Oxide region <NUM> may cover the entire top surface of substrate top electrode <NUM> and/or intermediate layer <NUM>. In other embodiments, only part of the top surface intermediate layer <NUM> is covered by oxide region <NUM>. In some, oxide may be applied such that oxide region <NUM> contacts, or completely covers the thickness of, reference layer <NUM>, transition layer <NUM>, fixed region <NUM>, cap region <NUM>, and/or top electrode <NUM>. Oxide region <NUM> may be conformal around the magnetoresistive stack and cover the vertical side walls of one or more regions of the magnetoresistive stack (e.g., reference layer <NUM>, transition layer <NUM>, fixed region <NUM>, cap region <NUM>, and/or top electrode <NUM>).

In some embodiments, after oxide region <NUM> is formed, one or more etching processes (e.g., processes where one or more layers are etched, abraded, and/or otherwise polished) may be performed on the oxide-coated magnetoresistive stack. For example, referring to <FIG>, at least a portion of oxide region <NUM>, intermediate layer <NUM>, and/or free region <NUM> may be removed from the oxide-coated magnetoresistive structure. In some embodiments, at least a portion of free region <NUM> may be removed such that one or more side-walls of free region <NUM> have a tapered edge (i.e., free region <NUM> includes a tapered side-wall). For example, the bottom surface of free region <NUM> (e.g., the surface that contacts SH material <NUM>) may have a diameter (e.g., a width in the x or y direction) greater than a diameter of the top surface of free region <NUM> (e.g., the surface that contacts intermediate layer <NUM>).

Referring to <FIG>, after a free region <NUM> including a tapered side-wall is formed, at least a portion of intermediate layer <NUM>, free region <NUM>, and/or SH material <NUM> may be removed to form a stack <NUM> that is asymmetrical with respect to a longitudinal axis of SH material <NUM>. For example, a cross-section near the top of stack <NUM> (e.g., a cross section including top electrode <NUM> and oxide region <NUM>) may have a smaller diameter than a cross-section near the bottom of stack <NUM> (e.g., a cross section including free region <NUM>). In some embodiments, free region <NUM> may be "over-etched. " Stated differently, a portion of SH material <NUM>, below the etched portion of free region <NUM>, may also be removed by the etch.

Referring to <FIG>, a cross-section in the z-y plane of stack <NUM>, after at least a portion of intermediate layer <NUM>, free region <NUM>, and/or SH material <NUM> are removed, is symmetrical with respect to a longitudinal axis of stack <NUM>. As described previously, when current <NUM> is passed through SH material <NUM>, spin current <NUM> is injected into free region <NUM> from SH material <NUM>. Referring to <FIG>, a cross-section in the z-y plane of stack <NUM>, after at least a portion of intermediate layer <NUM>, free region <NUM>, and/or SH material <NUM> are removed, is asymmetrical with respect to a longitudinal axis of stack <NUM>. As shown in <FIG>, the magnetic moments <NUM> of free region <NUM> combine to form an overall magnetic moment in free region <NUM> towards the removed portion of free region <NUM> (e.g., towards a side-wall that is no longer tapered). This asymmetrical magnetic moment may assist in imparting the desired magnetic properties into stack <NUM> and/or promoting, facilitating, maintaining, or otherwise assisting in the transfer of spin current <NUM> from SH material <NUM> to free region <NUM>. Although the right wall of free region <NUM> is shown to be vertical in <FIG>, this is one example. In other embodiments, free region <NUM> may still have tapered side-walls as long as the composite magnetic moments <NUM> of free region <NUM> are asymmetrical.

The shape of the stack shown in <FIG> may be formed, for example, by performing a selective angle etch on the magnetoresistive stack <NUM> comprising a free region <NUM> including a tapered side-wall. As would be recognized by a person skilled in the art, typically, the substrate being etched is rotated during etching (e.g., by ion beam etching (IBE)). In some embodiments, the magnetoresistive structure is not rotated while an angled etch is performed, removing more material on one side of the stack <NUM> than an opposing side of stack <NUM>.

Referring again to the oxide-coated magnetoresistive stack shown in <FIG>, a selective angle etch may be performed on the oxide-coated magnetoresistive stack to remove at least a portion of oxide region <NUM>. In some embodiments, the magnetoresistive structure is not rotated while an angled etch is performed, removing more material on one side of the stack <NUM> than an opposing side of stack <NUM>. After a portion of oxide region <NUM> is removed from the oxide-coated magnetoresistive stack, an asymmetrical magnetoresistive stack <NUM>, such as, for example, the stack <NUM> shown in <FIG>, may be formed.

Still referring to <FIG>, after at least a portion of oxide region <NUM> is removed, magnetoresistive stack <NUM> may include one or more oxide regions <NUM> disposed above and in contact with intermediate layer <NUM>. Oxide region <NUM> may cover the entire top surface of substrate top electrode <NUM> and/or intermediate layer <NUM>. In other embodiments, only part of the top surface intermediate layer <NUM> is covered by oxide region <NUM>. In some embodiments, oxide region <NUM> contacts, or completely covers the thickness of, reference layer <NUM>, transition layer <NUM>, fixed region <NUM>, cap region <NUM>, and/or top electrode <NUM>. Even after at least a portion of oxide region <NUM> is removed, oxide region <NUM> may be conformal around the magnetoresistive stack and cover the vertical side walls of one or more regions of the magnetoresistive stack (e.g., reference layer <NUM>, transition layer <NUM>, fixed region <NUM>, cap region <NUM>, and/or top electrode <NUM>).

After a selective angle etch is performed on an oxide-coated magnetoresistive stack (resulting in, e.g., the asymmetrical structure shown in <FIG>), at least a portion of SH material <NUM>, free region <NUM>, intermediate layer <NUM>, reference layer <NUM>, transition layer <NUM>, fixed region <NUM>, cap region <NUM>, top electrode <NUM> and/or cap region <NUM> may be removed, resulting in an asymmetrical magnetoresistive structure, such as, for example, the one shown in <FIG>. In some embodiments, at least a portion of free region <NUM> may be removed such that one or more side-walls of free region <NUM> have a tapered edge (i.e., free region <NUM> includes a tapered side-wall). For example, the bottom surface of free region <NUM> (e.g., the surface that contacts SH material <NUM>) may have a diameter (e.g., a width in the x or y direction) greater than a diameter of the top surface of free region <NUM> (e.g., the surface that contacts intermediate layer <NUM>).

Referring to <FIG>, after a free region <NUM> including a tapered side-wall is formed, the stack <NUM> may be asymmetrical with respect to a longitudinal axis of SH material <NUM>. For example, a cross-section near the top of stack <NUM> (e.g., a cross section including top electrode <NUM> and oxide region <NUM>) may have a smaller diameter than a cross-section near the bottom of stack <NUM> (e.g., a cross section including free region <NUM>). In some embodiments, free region <NUM> may be "over-etched. " Stated differently, a portion of SH material <NUM>, below the etched portion of free region <NUM>, may also be removed by the etch.

Referring to <FIG>, a cross-section in the z-y plane of stack <NUM>, after the free region <NUM> with a tapered side-wall is formed, is symmetrical with respect to a longitudinal axis of stack <NUM>. As described previously, when current <NUM> is passed through SH material <NUM>, spin current <NUM> is injected into free region <NUM> from SH material <NUM>. Referring to <FIG>, a cross-section in the z-y plane of stack <NUM>, after the free region <NUM> with a tapered side-wall is formed, is asymmetrical with respect to a longitudinal axis of stack <NUM>. As shown in <FIG>, the magnetic moments <NUM> of free region <NUM> combine to form an overall magnetic moment in free region <NUM> towards the removed portion of free region <NUM> (e.g., towards a side-wall that is no longer tapered). As described above, this asymmetrical magnetic moment may assist in imparting the desired magnetic properties into stack <NUM> and/or promoting, facilitating, maintaining, or otherwise assisting in the transfer of spin current <NUM> from SH material <NUM> to free region <NUM>. Although the right wall of free region <NUM> is shown to be angled with respsect to a vertical axis and non-parallel to the right wall of intermediate layer <NUM>, this is one example. In other embodiments, free region <NUM> may have one or more vertical side-walls, as long as the composite magnetic moments <NUM> of free region <NUM> are asymmetrical.

<FIG> is a flow chart of a method <NUM> of manufacturing a magnetoresistive structure <NUM> utilizing STT and/or SOT switching, according to one or more embodiments of the present disclosure. The method <NUM> may include forming an SH material <NUM> segment (step <NUM>). The method <NUM> may further include forming a magnetoresistive stack <NUM> including one or more insertion layers <NUM>, <NUM>, <NUM>, <NUM>, where each insertion layer <NUM>, <NUM>, <NUM>, <NUM> includes an antiferromagnetic material (step <NUM>). In some embodiments, the method <NUM> may include applying a magnetic field to the magnetoresistive stack <NUM> (step <NUM>). The method <NUM> may further include annealing the magnetoresistive stack <NUM>, wherein, after annealing, the one or more insertion layers <NUM>, <NUM>, <NUM>, <NUM> have a magnetic moment parallel or antiparallel to the SH material segment (step <NUM>).

<FIG> is a flow chart of a method <NUM> of manufacturing a magnetoresistive structure <NUM> utilizing STT and/or SOT switching, according to one or more embodiments of the present disclosure. The method <NUM> may include forming a magnetoresistive stack <NUM>, including a dielectric layer (e.g., intermediate layer <NUM>) and a free region <NUM>, on a segment of SH material <NUM> (step <NUM>). The method <NUM> may further include removing at least a portion of one or more layers of the magnetoresistive stack <NUM>, exposing at least a portion of the dielectric layer (e.g., intermediate layer <NUM>), and forming an etched magneto resistive stack (step <NUM>). In some embodiments, the method <NUM> may include depositing an auxiliary oxide on the etched magnetoresistive stack, forming an oxide region <NUM> (step <NUM>). The method <NUM> may further include removing at least a portion of each of the auxiliary oxide (e.g., from an oxide region <NUM>), the dielectric layer, and the free region <NUM>, forming a free region <NUM> including a tapered side-wall (step <NUM>). In some examples, method <NUM> may further include using a selective angle etch to remove at least a portion of the free region <NUM> including a tapered sidewall (step <NUM>).

<FIG> is a flow chart of a method <NUM> of manufacturing a magnetoresistive structure <NUM> utilizing STT and/or SOT switching, according to one or more embodiments of the present disclosure. The method <NUM> may include forming a magnetoresistive stack <NUM>, including a dielectric layer (e.g., intermediate layer <NUM>) and a free region <NUM>, on a segment of SH material <NUM> (step <NUM>). The method <NUM> may further include removing at least a portion of one or more layers of the magnetoresistive stack <NUM>, exposing at least a portion of the dielectric layer (e.g., intermediate layer <NUM>), and forming an etched magneto resistive stack (step <NUM>). In some embodiments, the method <NUM> may include depositing an auxiliary oxide on the etched magnetoresistive stack, forming an oxide region <NUM> (step <NUM>). The method <NUM> may further include removing at least a portion of the auxiliary oxide (e.g., from an oxide region <NUM>) using a selective angle etch (step <NUM>). In some examples, method <NUM> may further include removing at least a portion of each of the auxiliary oxide (e.g., from an oxide region <NUM>), the dielectric layer (e.g., intermediate layer <NUM>), and the free region <NUM>, forming a free region <NUM> including a tapered side-wall.

As alluded to above, the magnetoresistive devices of the present disclosure, including one or more switching geometries described herein, may be implemented in a sensor architecture or a memory architecture (among other architectures). For example, in a memory configuration, the magnetoresistive devices may be electrically connected to an access transistor and configured to couple or connect to various conductors, which may carry one or more control signals, as shown in <FIG>. The magnetoresistive devices of the current disclosure may be used in any suitable application, including, e.g., in a memory configuration. In such instances, the magnetoresistive devices may be formed as an integrated circuit comprising a discrete memory device (e.g., as shown in <FIG>) or an embedded memory device having a logic therein (e.g., as shown in <FIG>), each including MRAM, which, in one embodiment is representative of one or more arrays of MRAM having a plurality of magnetoresistive stacks, according to certain aspects of certain embodiments disclosed herein.

In one embodiments, a magnetoresistive device is disclosed. The device includes a top electrode, a magnetically fixed region, a magnetically free region positioned above or below the magnetically fixed region, and an intermediate region (e.g., a dielectric layer) positioned between the magnetically fixed region and the magnetically free region. The magnetoresistive device may also include a spin Hall material proximate to at least a portion of the free region and an insertion layer disposed between the SH material and the top electrode, wherein the insertion layer comprises antiferromagnetic material.

Various embodiments of the disclosed magnetoresistive device may additionally or alternatively also include one or more of the following features: the insertion layer may comprise manganese; the SH material may comprise at least one of platinum, beta-tungsten, tantalum, palladium, hafnium, gold, an alloy including gold, an alloy including bismuth and selenium, an alloy including copper, an alloy including manganese, iridium, selenium, or one or more combinations thereof; the insertion layer may have a thickness less than or equal to approximately <NUM> nanometers; according to the invention, the insertion layer is a first insertion layer and the device further comprises a second insertion layer; a transition layer between the dielectric layer and the fixed region, and a cap region between the fixed region and the top electrode, wherein the first insertion layer, the second insertion layer are both in contact with the cap region or the transition layer. The device may further comprise a third insertion layer in contact with the cap region or the transition layer.

In another embodiment, a magnetoresistive device is disclosed. The magnetoresistive device may include a magnetically fixed region, a magnetically free region positioned above or below the magnetically fixed region, and an intermediate region (e.g., a dielectric layer) positioned between the magnetically fixed region and the magnetically free region. A spin Hall channel material may be proximate to at least a portion of the magnetically free region. A cap region may be on the opposite of the fixed region from the free region. The device may include a transition layer between the intermediate layer and the fixed region and at least one insertion layer adjacent to the cap region or the transition layer, wherein the at least one insertion layer comprises antiferromagnetic material.

Various embodiments of the disclosed magnetoresistive device may additionally or alternatively also include one or more of the following features: the insertion layer may comprise manganese; the insertion layer may further comprise iridium or platinum; the insertion layer may have a thickness less than or equal to approximately <NUM> nanometers; current flowing in a first direction through the SH material may switch the free region to the first magnetic state, and current flowing in a second direction may switch the free region to the second magnetic state; the fxed region may include a synthetic antiferromagnetic structures (SAF). According to the invention, the at least one insertion layer is a first insertion layer and the device further comprises a second insertion layer adjacent to the cap region or the transition layer and a reference layer between the transition layer and the dielectric layer.

In another embodiment, a method of fabricating a magnetoresistive device is disclosed. The method may include forming a segment of SH material and forming a magnetoresistive stack in contact with the SH material, wherein the magnetoresistive stack includes a dielectric layer and a free region configured to switch between a first magnetic state and a second magnetic state. The method may also include removing at least a portion of one or more layers of the magnetoresistive stack to form an etched magnetoresistive stack. The method may further include depositing oxide (and/or nitride), thereby forming at least one oxide region. The method may also include, removing at least a portion of the oxide region and/or removing at least a portion of the free region, forming a free region including a tapered side wall.

Various embodiments of the disclosed method may also include one or more of the following features: a second etching step including the step of removing at least a portion of the oxide region, the step of removing at least a portion of the free region, or both; a selective angle etch; removing at least a portion of one or more layers of the magnetoresistive stack to form the etched magnetoresistive stack may include exposing at least a portion of the dielectric layer; and/or after forming a free region including a tapered side-wall, the magnetoresistive stack may be asymmetrical about a longitudinal axis of the magnetoresistive stack that is perpendicular to a surface of SH material that is in contact with free region.

Claim 1:
A magnetoresistive device (<NUM>) comprising:
a top electrode (<NUM>);
a fixed region (<NUM>), the fixed region (<NUM>) having a fixed magnetic state;
a cap region (<NUM>) above the fixed region (<NUM>) and below the top electrode (<NUM>);
a free region (<NUM>) below the fixed region (<NUM>), wherein the free region (<NUM>) is configured to have a first magnetic state and a second magnetic state;
a dielectric layer (<NUM>) between the free region (<NUM>) and the fixed region (<NUM>);
a transition layer (<NUM>) between the dielectric layer (<NUM>) and the fixed region (<NUM>);
a reference layer (<NUM>) between the transition layer (<NUM>) and the dielectric layer (<NUM>);
a spin-Hall (SH) material (<NUM>) proximate to at least a portion of the free region (<NUM>); and
a first insertion layer (<NUM>, <NUM>, <NUM>, <NUM>) disposed between the SH material (<NUM>)
and the top electrode (<NUM>) in contact with the cap region (<NUM>) or the transition layer (<NUM>) and a second insertion layer (<NUM>, <NUM>, <NUM>, <NUM>) disposed between the SH material (<NUM>) and the top electrode (<NUM>) in contact with the cap region (<NUM>) or the transition layer (<NUM>), wherein each of first and the second insertion layer (<NUM>, <NUM>, <NUM>, <NUM>) comprises antiferromagnetic material.