Magnetoresistive devices and methods therefor

Abstract

This invention discloses a magnetoresistive stack or structure of a magnetoresistive device, comprising one or more electrodes or conductive lines, a magnetically fixed region, a magnetically free region disposed between the electrodes or conductive lines, and a dielectric layer disposed between the free region and the fixed region. The magnetoresistive device may further include a spin Hall (SH) material adjacent to at least a portion of the free region and one or more intercalation layers including antiferromagnetic materials.

Description

Technical Field

[0001] The present invention relates in particular to magnetoresistive devices and methods for manufacturing and / or using the disclosed magnetoresistive devices. Summary of the Invention

[0002] In one or more embodiments, the present invention relates to a magnetoresistive device having a magnetoresistive stack or structure (e.g., part of a magnetoresistive memory device and / or a magnetoresistive sensor / sensor device) and a method of manufacturing and operating the described magnetoresistive device. In one embodiment, an exemplary magnetoresistive stack of the present invention (e.g., for use in a magnetic tunneling junction (MTJ) magnetoresistive device) comprises one or more layers of magnetic or ferromagnetic material.

[0003] In short, the magnetoresistive stack of the present invention for a memory device (e.g., a magnetoresistive random access memory (MRAM)) includes at least one non-magnetic layer (e.g., at least one dielectric layer or a non-magnetic but conductive layer) disposed between a "fixed" magnetic region and a "free" magnetic region. The "fixed" magnetic region and the "free" magnetic region each include one or more ferromagnetic material layers. Information is stored in the magnetoresistive memory stack by switching, programming, and / or controlling the direction of the magnetization vector in the magnetic layers(s) of the free magnetic region. The direction of the magnetization vector in the free magnetic region can be switched and / or programmed (e.g., via spin-orbit torque (SOT) and / or spin-transfer torque (STT)) adjacent to or through the magnetoresistive memory stack by applying a write signal (e.g., one or more current pulses). In contrast, the magnetization vector in the magnetic layer of a fixed magnetic region is magnetically fixed along a predetermined direction during the application of the write signal. A magnetoresistive memory stack has a first magnetic state when the magnetization vector of a free magnetic region adjacent to a non-magnetic layer is in the same direction as the magnetization vector of a fixed magnetic region adjacent to a non-magnetic layer. Conversely, a magnetoresistive memory stack has a second magnetic state when the magnetization vector of a free magnetic region adjacent to a non-magnetic layer is in the opposite direction to the magnetization vector of a fixed magnetic region adjacent to a non-magnetic layer. The magnetoresistive memory stack has different resistances in the first and second magnetic states. For example, the resistance (e.g., electrical resistance) of the second magnetic state may be relatively higher than that 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, for example, applying a read current through the magnetoresistive stack.

[0004] As magnetic memory devices (such as MRAM) evolve towards smaller program nodes to increase density, the size of individual MTJ bits must be reduced laterally to accommodate tighter pitch and space between bits. However, as the size and / or aspect ratio of MTJ bits decreases, their shape magnetic anisotropy also weakens. With weakened shape anisotropy, the MTJ barrier decreases. However, with a reduced barrier, the data retention and / or thermal stability of the MTJ bit also weaken. Typically, the reduction in the MTJ barrier can be corrected by increasing its vertical anisotropy or magnetic moment by changing the composition / material / thickness of the free region. However, doing so also increases the critical current of the MTJ bit (described in more detail below). MTJ bits with high critical currents experience more periodic damage and degradation during write and / or reset operations, negatively impacting the durability of the MTJ device (i.e., MRAM).

[0005] This invention relates to devices (e.g., devices comprising 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 specifically, the following description describes embodiments of MTJ geometries that individually or in combination integrate SOT and / or STT switching mechanisms to provide improved switching efficiency to achieve switching of a high-barrier MTJ bit without using unnecessarily high amounts of write current. However, the scope of this invention is defined by the appended claims and not by any features of the resulting device or method. Simple Explanation of the Diagram

[0006] Embodiments of the invention can be implemented in conjunction with the forms illustrated in the accompanying drawings. These drawings illustrate different forms of the invention, and similarly, element symbols representing the same structures, components, materials, and / or elements are labeled in different drawings as appropriate. It should be understood that various combinations of structures, components, and / or elements other than those specifically shown are also conceivable and within the scope of the invention.

[0007] For simplicity and clarity, the figures depict the general structure and / or construction of the various embodiments described herein. For ease of illustration, the figures depict different layers / regions of the illustrated magnetoresistive stack as having a uniform thickness and clearly defined boundaries with straight edges. However, those skilled in the art will recognize that, in practice, the different layers typically have a non-uniform thickness. Furthermore, at the interfaces between adjacent layers, the materials of these layers may be cast together as an alloy or migrated to one or another material, thus obscuring their boundaries. Descriptions and details of well-known features (e.g., interconnects, etc.) and techniques may be omitted to avoid obscuring other features. Components in the figures are not necessarily drawn to scale. The dimensions of some features may be enlarged relative to other features to facilitate understanding of the illustrative embodiments. The figures are simplified diagrams provided to help illustrate the relative positioning of various regions / layers and describe various processing steps. Those skilled in the art should understand that the regions are not necessarily drawn to scale and should not be considered as representing proportional relationships between different regions / layers. Furthermore, although certain areas / layers and features are depicted as having straight 90° edges, in fact or in reality, such areas / layers may be more "rounded", curved and / or gradually tilted.

[0008] Furthermore, those skilled in the art will understand that although the figures depict multiple layers with clear interfaces, in some cases, over time and / or exposure to high temperatures, material from some layers may migrate into the material of other layers or interact with the material of other layers to create a more diffuse interface between these layers. It should be noted that even if not specifically mentioned, the manner described with reference to one embodiment can be applied to other embodiments and used in conjunction with other embodiments.

[0009] Furthermore, numerous embodiments are described and illustrated herein. The invention is not limited to any single form and embodiment thereof, nor is it limited to any combination and / or arrangement of such forms and / or embodiments. Moreover, various forms and / or embodiments of the invention may be used alone or in combination with one or more other forms and / or embodiments of the invention. For the sake of brevity, specific arrangements and combinations are not discussed and / or illustrated herein. It is important to note that one embodiment or implementation described herein as "illustrative" should not be construed as being better than or superior to other embodiments or implementations; rather, it is intended to reflect or indicate that (a number of) embodiments are (a number of) "exemplary" embodiments. Furthermore, even though the figures and the invention appear to depict the magnetoresistive stack of the disclosed magnetoresistive device in a particular construction order (e.g., bottom-up), it should be understood that the depicted magnetoresistive stack may have a different order (e.g., the reverse order (i.e., top-down)).

[0010] Figures 1 to 16 illustrate schematic diagrams of a region of a magnetoresistive structure utilizing an SOT and / or STT switching mechanism according to one or more embodiments of the present invention;

[0011] Figure 17A illustrates a region of a magnetoresistive structure utilizing an SOT and / or STT switching mechanism according to one or more embodiments of the present invention;

[0012] Figure 17B illustrates a top view of a cross-section of the magnetoresistive structure shown in Figure 17A according to one or more embodiments of the present invention;

[0013] Figure 18 illustrates a side view of a magnetoresistive structure during a manufacturing stage according to one or more embodiments of the present invention;

[0014] Figure 19 illustrates a side view of a magnetoresistive structure during a manufacturing stage according to one or more embodiments of the present invention;

[0015] Figure 20 illustrates a side view of a magnetoresistive structure during a manufacturing stage according to one or more embodiments of the present invention;

[0016] Figure 21 illustrates a side view of a magnetoresistive structure during a manufacturing stage according to one or more embodiments of the present invention;

[0017] Figure 22A illustrates a side view of a magnetoresistive structure during the manufacturing stage according to one or more embodiments of the present invention;

[0018] Figure 22B shows a vertical side view of one of the magnetoresistive structures shown in Figure 22A;

[0019] Figure 22C shows a top view of one of the magnetoresistive structures shown in Figures 22A and 22B;

[0020] Figure 23 illustrates a side view of a magnetoresistive structure during the manufacturing stage according to one or more embodiments of the present invention;

[0021] Figure 24A illustrates a side view of a magnetoresistive structure during the manufacturing stage according to one or more embodiments of the present invention;

[0022] Figure 24B shows a vertical side view of one of the magnetoresistive structures shown in Figure 24A;

[0023] Figure 24C shows a top view of one of the magnetoresistive structures shown in Figures 24A and 24B;

[0024] Figures 25 to 27 are flowcharts illustrating one or more exemplary procedures for manufacturing a magnetoresistive structure utilizing one of the SOT and / or STT switching mechanisms;

[0025] Figure 28 is a schematic diagram of an exemplary magnetoresistive memory stack electrically connected to a selection device (e.g., a transistor) in a magnetoresistive memory cell configuration;

[0026] Figures 29A and 29B are schematic block diagrams of integrated circuits comprising a discrete memory device including an MRAM (which in one embodiment represents one or more MRAM arrays having a pattern of a particular embodiment of the present invention) and an embedded memory device.

[0027] To reiterate, numerous embodiments are described and illustrated herein. The invention is not limited to any single form or embodiment thereof, nor to any combination and / or arrangement of such forms and / or embodiments. Various forms and / or embodiments of the invention may be used alone or in combination with one or more other forms and / or embodiments of the invention. For the sake of brevity, these various combinations and arrangements are not discussed separately herein. Implementation

[0028] It should be noted that all numerical values ​​disclosed herein (including all disclosed thickness values, limits, and ranges) may vary by ±10% from the disclosed values ​​(unless a different variation is specified). For example, a layer disclosed as being "t" units thick may vary in thickness from (t-0.1t) units to (t+0.1t) units. Furthermore, all relative terms such as "approximately," "substantially," "about," etc., are used to indicate a possible variation of ±10% (unless another variation is mentioned or specified). Additionally, in the claims, for example, the values, limits, and / or ranges of the thickness and atomic composition of the described layers / regions mean values, limits, and / or ranges ±10%.

[0029] It should be noted that the descriptions set forth herein are illustrative only and are not intended to limit the embodiments of the subject matter or the application and use of such embodiments. Any embodiment described herein as "illustrative" should not be construed as being better than or superior to other embodiments. Rather, the term "illustrative" as used is intended to be exemplary or "illustrative" rather than "ideal." The terms "comprising," "including," "having," "containing," and any variations thereof are used synonymously to indicate or describe a non-exclusive inclusion. Thus, an apparatus or method using these terms may include not only those elements or steps but also other elements and steps not expressly listed or inherent to the apparatus and method. Furthermore, the terms "first," "second," and the like herein do not indicate any order, quantity, or importance but are used to distinguish elements from each other. Similarly, terms of relative orientation such as "top," "bottom," etc., are used with reference to the orientation of the structures illustrated in the described figures. Moreover, the term "a" herein does not indicate a quantity limitation but rather indicates the presence of at least one reference.

[0030] It should be further noted that although exemplary embodiments have been described in the context of MTJ stacks / structures, the present invention can also be implemented in conjunction with giant magnetoresistive (GMR) stacks / structures in which a conductor (e.g., a copper layer) is disposed between two ferromagnetic regions / layers / materials. Embodiments of the present invention can be employed in conjunction with other types of magnetoresistive stacks / structures, wherein such stacks / structures include a fixed magnetic region. For the sake of brevity, the discussions and descriptions presented in the present invention will not be specifically repeated in the context of GMR or other magnetoresistive stacks / structures (e.g., anisotropic magnetoresistive (AMR) devices), but the discussions and figures described below should be interpreted as fully applicable to GMR and other magnetoresistive stacks / structures (e.g., AMR type devices).

[0031] In this invention, the term "region" is generally used to refer to one or more layers. That is, a region (as used herein) may comprise a single material layer (deposit, film, coating, etc.) or multiple material layers stacked one on top of the other (i.e., a multilayer structure). Furthermore, although different regions and / or layers in the disclosed magnetoresistive device may be referred to by specific names (e.g., bottom electrode, top electrode, fixed magnetic region, free magnetic region) in the following description, this is merely for ease of description and is not intended to be a functional description or relative position / orientation of the layers. Moreover, although the following description and figures appear to depict layers with a particular orientation relative to each other, those skilled in the art will understand that such descriptions and depictions are merely illustrative. For example, although a free region of a magnetoresistive stack may be depicted "above a spin Hall (SH) material," in some cases, the entire depicted magnetoresistive structure may be flipped so that the free region is "below the SH material."

[0032] In one exemplary embodiment, a magnetoresistive structure of one of the magnetoresistive devices of the present invention may be implemented as an STT and / or SOT MRAM element. In these 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 a ferromagnetic region having a magnetic moment that is significantly displaced or moved in response to an applied magnetic field or spin-polarized current used to switch the magnetic moment vector. Accordingly, the terms "fixed" or "pinned" are used to refer to a ferromagnetic region having a magnetic moment vector that is substantially unmoved in response to such applied magnetic field or spin-polarized current. As is known in this art, the resistance of one of the magnetoresistive structures described can be changed based on the parallel or antiparallel alignment of the magnetization direction (e.g., the direction of the magnetic moment) of a free region adjacent to a nonmagnetic layer (e.g., a tunneling barrier) with the magnetization direction (e.g., the direction of the magnetic moment) of a fixed region adjacent to the nonmagnetic layer. Typically, if the two regions have the same magnetization alignment, the resulting relatively lower resistance is considered a bit "0," while if the alignment is antiparallel, the resulting relatively higher resistance is considered a bit "1." A memory device (e.g., an MRAM) may include multiple magnetoresistive structures / stacks configured in an array of rows and columns, which may refer to memory cells or elements. The resistance of each cell can be read by measuring the current through each cell, and thus the data stored in the memory array can be read.

[0033] In some embodiments, the free magnetic region and the fixed magnetic region may each comprise a plurality of magnetic or ferromagnetic material layers, such as materials comprising one or more of the ferromagnetic elements nickel (Ni), iron (Fe), and cobalt (Co), and alloys or engineered materials having, for example, one or more of the elements palladium (Pd), platinum (Pt), magnesium (Mg), manganese (Mn), chromium (Cr), and boron (B) and one or more synthetic antiferromagnetic structures (SAF) or synthetic ferromagnetic structures (SyF). The magnetic material layers may also comprise one or more non-magnetic material layers (e.g., ruthenium (Ru), copper (Cu), aluminum (Al), tantalum (Ta), titanium (Ti), niobium (Nb), vanadium (V), zirconium (Zr), iridium (Ir), and their alloys, and tungsten (W) and molybdenum (Mo) in specific embodiments). An intermediate layer (e.g., a dielectric layer) may be, for example, one or more layers of aluminum oxide and / or magnesium oxide.

[0034] In a magnetoresistive device utilizing the SOT switching mechanism, magnetization switching of the free region of a magnetoresistive stack can be accomplished or facilitated by driving a current pulse through an SH material that is close to (e.g., in contact with or near) the free region. Examples of SH materials include (but are not limited to) platinum (Pt), β-tungsten (β-W), tantalum (Ta), palladium (Pd), hafnium (Hf), gold (Au), alloys containing gold (e.g., AuPt, AuCu, AuW), alloys containing bismuth (Bi) and selenium (Se) (e.g., Bi2Se3 or (BiSe)2Te3), alloys containing copper (Cu) and one or more of platinum (Pt), bismuth (Bi), iridium (Ir), or lead (Pb) (e.g., CuPt alloy, CuBi alloy, CuIr alloy, CuPb alloy), alloys containing silver (Ag) and bismuth (Bi) (e.g., AgBi alloy), alloys containing manganese (Mn) and one or more of platinum (Pt), iridium (Ir), palladium (Pd), or iron (Fe) (e.g., PtMn alloy, IrMn alloy, PdMn alloy, FeMn alloy), or combinations thereof.

[0035] The average current required to change the magnetic state of a free region is referred to as the critical current (IC). The critical current indicates the current required to "write" data into a magnetoresistive memory cell. Reducing the critical current is desirable to allow for smaller transistors in each memory cell and to produce higher-density, lower-cost memory, etc. A reduction in the critical current can also lead to a longer lifespan and / or durability of a magnetoresistive memory cell.

[0036] The embodiments described herein utilize so-called spin currents to switch or facilitate switching the magnetic state of a free region in an MTJ or MTJ-type device. A spin torque is caused by a current flowing through a SH material adjacent to (and / or in contact with) the free region. This spin current acts on the free region due to spin-dependent scattering of electrons from the SH material. The direction of the applied spin current is determined by the polarity of the current in the SH material and the polarity of the SH material itself. The spin current is injected into the free region along a direction perpendicular to the boundary (or interface) where the free region and the SH material meet and orthogonal to the current flow direction. The spin torque applied to the free region by the spin current affects the magnetic state of the free region in a manner similar to that of a spin-polarized tunneling current flowing through an MTJ in a conventional STT magnetic tunneling junction. Since the function of the STT magnetic tunneling junction is well known in this art, it will not be described further here.

[0037] Similar to the write current in conventional STT MTJ devices, in devices using the SOT switching mechanism, the direction of the torque applied by the spin current depends on the direction of current flow in the SH material. In other words, the direction of current flow within the SH material near the free region determines the direction of the torque applied to the free region. Therefore, the free region can switch between two stable states based on the torque applied by a current flowing in one direction or another near the SH material. In some embodiments, the free region can switch between two stable magnetic states based on the torque applied by an STT current flowing through one of the MTJs in either direction. The magnetic state of the free region can also be switched by the torque resulting from both the spin torque of a spin current injected from one or more SH materials through a current applied to one of the MTJ bits and the spin torque of a charging current applied through one or more SH materials.

[0038] In some embodiments, the torque applied solely by the spin current (i.e., the SOT current) is used to switch the free region to a specific magnetic state. In other embodiments, the spin current is used as an "auxiliary" measure of one of the STT write current values ​​required to switch the magnetic state of the free region, wherein the STT write current travels through the entire MTJ stack to generate a spin-polarized tunneling current between the free and stationary regions. Reading of data stored in the MTJ stack is performed as with a conventional STT MTJ device. For example, a read current having a value less than a critical current of the MTJ stack is applied to the MTJ stack to sense the resistance of the MTJ stack. Those skilled in the art will recognize that numerous techniques can 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 to a reference resistance to determine the state of the free region. In some embodiments, a self-reference read operation is performed, wherein the resistance through the MTJ is sensed, then the MTJ is written to (or reset) to bring the free region to a known state, and then the resistance is sensed again and compared to the initially sensed resistance. Next, the initial state of the free region can be determined based on whether the resistance sensing has changed based on a write or reset operation. In other embodiments, a midpoint reference read operation can be performed.

[0039] For the sake of brevity, conventional techniques related to semiconductor processing will not be described in detail here. Exemplary embodiments can be fabricated using known lithography processes. The fabrication of integrated circuits, microelectronic devices, microelectromechanical devices, microfluidic devices, and photonic devices involves creating layers or regions (e.g., comprising one or more layers) of materials that interact in a certain manner. One or more of these regions can be patterned such that the various regions of the layers have different electrical or other properties, which can be interconnected within or to other regions to create electrical components and circuits. These regions can be created by selectively introducing or removing various materials. The patterns defining these regions are typically generated by lithography processes. For example, a photoresist layer is applied to a layer overlaid on a wafer substrate. A photomask (containing transparent and opaque areas) is used to selectively expose the photoresist by a form of radiation such as ultraviolet light, electrons, or X-rays. The photoresist exposed to or not exposed to radiation is removed by applying a developer. An etching process can then be employed / applied, in which the layer (or material) not protected by the remaining photoresist is patterned. Alternatively, an additive procedure can be used, in which a photoresist is used as a template to construct a structure.

[0040] As mentioned above, in one embodiment, the described embodiments are particularly related to a method of fabricating a magnetoresistive stack having one or more conductive electrodes, pathways, or conductors on both sides of a magnetic material stack. As will be described in further detail below, the magnetic material stack may comprise a number of different regions of material, some of which contain magnetic material while others do not. In one embodiment, the fabrication method includes sequentially depositing, growing, sputtering, evaporating, and / or providing (collectively referred to herein as "deposited") regions that, after further processing (e.g., etching), form a magnetoresistive stack.

[0041] In some embodiments, the disclosed magnetoresistive stack may be formed between a top electrode / path / line and a bottom electrode / path / line, and may be accessed by means of other elements that allow (e.g., electrical) connection to a circuit system and a magnetoresistive device. Between the electrodes / paths / lines are multiple regions comprising at least one fixed magnetic region (hereinafter referred to as a fixed region) and at least one free magnetic region (hereinafter referred to as a free region), and one or more intermediate layers (e.g., a dielectric layer) forming a tunneling barrier between the fixed and free regions. Each of the fixed and free regions may comprise a plurality of ferromagnetic layers, etc. In some embodiments, the fixed region (e.g., fixed region 160 discussed below) may comprise a synthetic antiferromagnetic (SAF). In some embodiments, a top electrode (and / or) and 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 positioned close to an SH material. The SH material may be configured to carry a charging current and apply a spin current to the free region during write and reset operations. In one or more embodiments, one or more electrodes of a magnetoresistive stack may comprise an SH material. In other embodiments, a magnetoresistive stack may be formed between a top electrode and a bottom electrode and close to an SH material, the SH material being independently connected to a current source. In these embodiments, the magnetoresistive structure or device may refer to a three-terminal magnetoresistive device.

[0042] According to one or more embodiments, a magnetoresistive structure may include a reference layer, a transition layer, and / or a capping region. For example, a transition layer may facilitate, advance, or otherwise contribute to the formation of a reference layer over an intermediate layer (e.g., a dielectric layer) without adversely affecting the properties of the reference layer or the intermediate layer. The transition layer may include a non-ferromagnetic transition metal, such as (e.g.) tantalum (Ta), titanium (Ti), tungsten (W), molybdenum (Mo), or combinations and alloys thereof.

[0043] The reference layer may comprise one or more material layers that promote and modify the growth of one or more overlying regions (e.g., a fixed region comprising a SAF) during the fabrication of the magnetoresistive structure 100. The reference layer may comprise, for example, cobalt (Co), iron (Fe), and boron (B), such as cobalt-iron-boron alloy (CoFeB), cobalt-iron-boron-tantalum alloy (CoFeBTa), cobalt-iron-tantalum alloy (CoFeTa), or combinations thereof. In some embodiments, the reference layer may comprise one or more alloys containing iron (Fe), cobalt (Co), or nickel (Ni) and other relatively electronegative elements (e.g., elements having an electronegativity greater than that of iron (Fe)). For example, the reference layer may comprise one or more alloys, such as (e.g.) an alloy of the formula XY, wherein the X group is selected from a list including cobalt (Co), iron (Fe), nickel (Ni), cobalt-iron (CoFe), iron-nickel (FeNi), and cobalt-nickel (CoNi), and the Y group is selected from a list including 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). The alloy contains one or more elements having a greater electronegativity than 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), and carbon (C)).

[0044] Referring now to Figures 1 through 16, various magnetoresistive structures (e.g., free regions, intermediate layers, fixed regions, one or more SH materials, and / or one or more other layers or regions) are illustrated with their relative positions and orientations. The simplified illustrative diagrams in Figures 1 through 16 do not necessarily show all regions and layers of an exemplary magnetoresistive structure, but are intended to depict the relative positions and orientations of several exemplary regions. Furthermore, although the regions depicted in Figures 1 through 16 are rectangular, this is merely for simplicity and clarity. The magnetoresistive structures described herein may have rectangular, trapezoidal, pyramidal, cylindrical, or other shapes.

[0045] Referring again to Figures 1 through 16, a magnetoresistive structure 100 may include one or more regions or layers between a line, strip, or region of SH material 110 and a top electrode 180. For example, referring to Figure 1, a free region 120 may be disposed on and in contact with the SH material 110. An intermediate layer 130 may be disposed on and in contact with the free region 120. A fixed region 160 may be disposed on the other side of the intermediate layer 130 relative to the free region 120. In some embodiments, the fixed region 160 may be disposed on and in contact with the intermediate layer 130. The magnetoresistive structure 100 may include one or more additional regions or layers, such as, for example, a cap region 170. The cap region 170 may be disposed above and in contact with the fixed region 160. The top electrode 180 may be disposed above the fixed region 160, such as, for example, disposed above and in contact with the cap region 170.

[0046] Referring again to Figures 1 through 16, for a read operation, current can be transferred from the SH material 110 through the magnetoresistive structure 100 to the top electrode 180. For a write and / or reset operation, current can be transferred along the SH material 110 to apply spin current to the free region 120. Additionally, a write current can also be transferred from the SH material 110 through the magnetoresistive structure 100 to the top electrode 180 to facilitate the switching of the magnetic state of the free region 120.

[0047] According to one or more embodiments, a magnetoresistive structure 100 may include one or more intercalation layers adjacent to the cap region 170 and / or the transition layer 150. Each of the one or more intercalation layers may include one or more antiferromagnetic (AFM) material layers, such as platinum manganese (PtMn) alloy, iridium manganese (IrMn) alloy, iron manganese (FeMn) alloy, chromium (Cr), and / or combinations thereof. In embodiments where a magnetoresistive structure 100 includes more than one intercalation layer, the composition of one intercalation layer may be the same as the composition of another intercalation layer and / or the composition of one intercalation layer may be different from at least one other intercalation layer.

[0048] Referring to Figures 2 through 5, the magnetoresistive structure 100 may include an insert layer 201 disposed between the reference layer 140 and the top electrode 180. For example, referring to Figure 2, the magnetoresistive structure 100 may include an insert layer 201 disposed between the cap region 170 and the top electrode 180. In some embodiments (such as the embodiment shown in Figure 3), the magnetoresistive structure 100 may include an insert layer 201 disposed between the fixed region 160 and the cap region 170. Referring to Figure 4, the magnetoresistive structure 100 may include an insert layer 201 disposed between the transition layer 150 and the fixed region 160. Alternatively or additionally, the magnetoresistive structure 100 may include an insert layer 201 disposed between the reference layer 140 and the transition layer 150, as shown in Figure 5.

[0049] The insertion layer 201 may have a thickness of less than or equal to about 2 nanometers (nm), such as (for example) less than or equal to about 1.5 nm, less than or equal to about 1 nm, about 1 nm to about 2 nm, about 1 nm to about 1.5 nm, about 0.5 nm to about 1.5 nm, about 0.5 nm to about 1.0 nm, about 0.7 nm, about 0.5 nm, or any other suitable thickness that will not harmfully affect the bidirectional transfer of current from the SH material 110 to the top electrode 180.

[0050] Referring to Figures 6 through 11, a magnetoresistive structure 100 may include a first insertion layer 201 and a second insertion layer 202. As described above, the terms "first," "second," and the like are used herein not to indicate any order, quantity, or importance, but rather to distinguish elements from one another. The first insertion layer 201 may have the same composition as the second insertion layer 202, or the insertion layers 201 and 202 may have different compositions. The second insertion layer 202 may have a thickness similar to that of the first insertion layer 201 described above. In some embodiments, the second insertion layer 202 may have a thickness less than that of the first insertion layer 201. In other embodiments, the second insertion layer 202 may have a thickness greater than that of the first insertion layer 201.

[0051] For example, referring to FIG. 6, a magnetoresistive structure 100 may include a first insert layer 201 disposed between a fixed region 160 and a cap region 170, and a second insert layer 202 disposed between the cap region 170 and a top electrode 180. In some embodiments (such as the embodiment shown in FIG. 7), a magnetoresistive structure 100 may include a first insert layer 201 disposed between a transition layer 150 and a fixed region 160, and a second insert layer 202 disposed between the cap region 170 and the top electrode 180. Referring to FIG. 8, a magnetoresistive structure 100 may include a first insert layer 201 disposed between a reference layer 140 and a transition layer 150, and a second insert layer 202 disposed between the cap region 170 and the top electrode 180. In some embodiments, the magnetoresistive structure 100 may include a first insert layer 201 disposed between the transition layer 150 and the fixed region 160 and a second insert layer 202 disposed between the fixed region 160 and the cap region 170, as shown in FIG9. Referring to FIG10, a magnetoresistive structure 100 may include a first insert layer 201 disposed between the reference layer 140 and the transition layer 150 and a second insert layer 202 disposed between the fixed region 160 and the cap region 170. Alternatively, the magnetoresistive structure 100 may include a first insert layer 201 disposed between the reference layer 140 and the transition layer 150 and a second insert layer 202 disposed between the transition layer 150 and the fixed region 160, as shown in FIG11.

[0052] Referring to Figures 12 to 15, a magnetoresistive structure 100 may include a first insertion layer 201, a second insertion layer 202, and a third insertion layer 203. The first insertion layer 201 may have the same composition as the second insertion layer 202 and the third insertion layer 203, or one or more insertion layers 201, 202, and 203 may have a composition different from at least one other insertion layer 201, 202, and 203. The third insertion layer 203 may have a thickness similar to that of the first insertion layer 201 or the second insertion layer 202, as described above. In some embodiments, the third insertion layer 203 may have a thickness less than that of the first insertion layer 201 and / or the second insertion layer 202. Alternatively, the third insertion layer 203 may have a thickness greater than that of the first insertion layer 201 and / or the second insertion layer 202.

[0053] For example, referring to FIG12, a magnetoresistive structure 100 may include a first insert layer 201 disposed between a transition layer 150 and a fixed region 160, a second insert layer 202 disposed between the fixed region 160 and a cap region 170, and a third insert layer 203 disposed between the cap region 170 and a top electrode 180. In another example, as shown in FIG13, the magnetoresistive structure 100 may include a first insert layer 201 disposed between a reference layer 140 and a transition layer 150, a second insert layer 202 disposed between the transition layer 150 and the fixed region 160, and a third insert layer 203 disposed between the cap region 170 and the top electrode 180. Referring to FIG14, in some embodiments, the magnetoresistive structure 100 may include a first insert layer 201 disposed between the reference layer 140 and the transition layer 150, a second insert layer 202 disposed between the fixed region 160 and the cap region 170, and a third insert layer 203 disposed between the cap region 170 and the top electrode 180. In some instances, the magnetoresistive structure 100 may include a first insert layer 201 disposed between the reference layer 140 and the transition layer 150, a second insert layer 202 disposed between the transition layer 150 and the fixed region 160, and a third insert layer 203 disposed between the fixed region 160 and the cap region 170, as shown in FIG15.

[0054] Referring to Figure 16, a magnetoresistive structure 100 may include four insertion layers (e.g., a first insertion layer 201, a second insertion layer 202, a third insertion layer 203, and a fourth insertion layer 204). In some embodiments, the fourth insertion layer 204 may have the same composition as the first insertion layer 201, the second insertion layer 202, and / or the third insertion layer 203. Alternatively, one or more insertion layers 201, 202, 203, and 204 may have a different composition than at least one of the other insertion layers 201, 202, 203, and 204. The fourth insertion layer 204 may have a thickness similar to that of the first insertion layer 201, the second insertion layer 202, or the third insertion layer 203, as described above. In some embodiments, the fourth insertion layer 204 may have a thickness less than that of the first insertion layer 201, the second insertion layer 202, and / or the third insertion layer 203. Alternatively, the fourth insertion layer 204 may have a thickness greater than that of the first insertion layer 201, the second insertion layer 202 and / or the third insertion layer 203.

[0055] Referring again to FIG16, the magnetoresistive structure 100 may include a first insertion layer 201 disposed between the reference layer 140 and the transition layer 150, a second insertion layer 202 disposed between the transition layer 150 and the fixed region 160, a third insertion layer 203 disposed between the fixed region 160 and the cap region 170, and a fourth insertion layer 204 disposed between the cap region 170 and the top electrode 180.

[0056] Without being limited by theory, including one or more insert layers 201, 202, 203, 204 can induce a local magnetic field. For example, after forming the magnetoresistive structure 100, one or more subsequent processing steps (e.g., annealing) can be performed, which induce a magnetic moment in one or more insert layers 201, 202, 203, 204 to generate a local magnetic field. The induced local magnetic field can promote, modify, and / or maintain the transfer of spin current from the SH material 110 to the free region 120.

[0057] For example, referring to Figure 17A, a magnetoresistive structure 100 may include an insert layer 201. The magnetic moment of the insert layer 201 (indicated by arrow 301) can induce a local stray magnetic field 304. The local stray magnetic field 304 may have a value of about 10 Ørsted (Oe) to about 600 Oe. When a current (indicated by arrow 302) passes through the SH material 110, a spin current (indicated by arrow 303) is applied from the SH material 110 to the free region 120. When the magnetic moments of one or more insert layers (e.g., insert layer 201) are parallel or antiparallel to the current 302 passing through the SH material 110, the induced local stray magnetic field 304 can facilitate the transfer of the spin current 303 from the SH material 110 to the free region 120.

[0058] Figure 17B shows a cross-section of the magnetoresistive structure 100 shown in Figure 17A along line 17B-17B. As can be seen in Figure 17B, one or more insert layers (e.g., insert layer 201) may be oval, elongated, elliptical, or other non-rectangular shapes. One or more other layers and / or regions of the magnetoresistive structure 100 (e.g., free region 120, intermediate layer 130, reference layer 140, transition layer 150, fixed region 160, cap region 170) may be oval, elongated, elliptical, or other non-rectangular shapes. The magnetoresistive structure 100, which includes one or more layers and / or regions with a non-rectangular shape, may have an anisotropy in the shape of the magnetic moments that contribute to the magnetic moments of one or more magnetic or antiferromagnetic layers of the magnetoresistive structure 100.

[0059] After forming one or more layers and / or regions of a magnetoresistive structure 100, further processing steps may be performed to ensure that the magnetoresistive device structure has the desired magnetic properties. For example, the further processing steps may include an annealing step to fix one or more insert layers 201, 202, 203, 204 and / or one or more magnetic layers (e.g., fixing the magnetic layer of region 160). During annealing, an external magnetic field may be applied. The magnitude and / or direction of the local stray magnetic field 304 induced by one or more insert layers 201, 202, 203, 204 may depend at least in part on the angle of the magnetic field applied during annealing. During annealing, a magnetic field may be applied along a line (e.g., the direction in which current travels through the SH material 110) incident on the SH material 110 at approximately 35° to approximately 55° (e.g., approximately 40° to approximately 50° or approximately 45°) in the xy plane. Other suitable incident angles can be used so that the resulting insert layers 201, 202, 203, 204 have a magnetic moment that is parallel or antiparallel to the direction of current flow through the SH material 110.

[0060] As previously described, one or more devices or systems may include a series of magnetoresistive structures 100 positioned along a linear SH material 110. Layers and regions connecting the magnetoresistive structures 100 above the SH material 110 may refer to a stack 200. For example, referring to the magnetoresistive structures 100 shown in FIG. 18, the stack 200 includes a free region 120, an intermediate layer 130, a reference layer 140, a transition layer 150, a fixed region 160, a cap region 170, and a top electrode 180. In other embodiments, the stack 200 may include one or more insert layers 201, 202, 203, 204. A segment of the SH material 110 may be connected to a series of stacks 200 configured in a row or other array.

[0061] In the above method, an external magnetic field is required during annealing to break the symmetry of the magnetoresistive structure 100 and induce a magnetic moment in one or more layers and / or regions of the stack 200. Alternatively, one or more layers and / or regions of the magnetoresistive structure 100 may be etched in a manner to create an asymmetric magnetoresistive structure 100 to apply the desired magnetic properties to one or more layers and / or regions of the stack 200. In Figures 18 to 24C, the stack 200 shown is similar to the stack 100 shown in Figure 1. However, this is only for illustrative purposes, and the method of this embodiment can be used with any stack 200 or magnetoresistive structure 100 described herein.

[0062] Referring to Figures 18 to 24C, similar to Figures 17A and 17B, each magnetoresistive structure 100 is drawn such that the SH material 110 is located in an xy-plane and each layer and / or region of each stack 200 is located in a generally parallel xy-plane with a z-axis displacement. The orientation of the regions, layers, and structures shown in Figures 18 to 24C is for illustrative purposes only. Other configurations, placements, and orientations of layers and / or regions may be considered.

[0063] An exemplary method for fabricating a magnetoresistive stack with SOT switching (e.g., a magnetoresistive stack comprising one of the geometries discussed above) will now be discussed with reference to Figures 18 to 24C. As previously stated, conventional techniques commonly performed in relation to semiconductor processing are not specifically described herein. Rather, the description herein is intended to emphasize the manner of an exemplary method for fabricating one of the magnetoresistive structures described herein.

[0064] Figure 18 illustrates a magnetoresistive structure during a process according to one or more embodiments of the present invention. For example, in at least one embodiment, Figure 18 illustrates a magnetoresistive structure after the formation of SH material 110, free region 120, intermediate layer 130, reference layer 140, transition layer 150, fixed region 160, cap region 170, and top electrode 180. As described above, each layer or region may lie in an xy plane displaced along a z-axis from each adjacent layer or region.

[0065] In some embodiments, after forming the SH material 110, free region 120, intermediate layer 130, reference layer 140, transition layer 150, fixed region 160, cap region 170, and top electrode 180, at least a portion of the top electrode 180, cap region 170, fixed region 160, transition layer 150, reference layer 140, and / or intermediate layer 130 may be removed (e.g., etched). For example, referring to FIG19, after removing at least a portion of the top electrode 180, cap region 170, fixed region 160, transition layer 150, reference layer 140, and / or intermediate layer 130, the remaining portions of the reference layer 140, transition layer 150, fixed region 160, cap region 170, and top electrode 180 may have a diameter smaller than the diameter of the free region 120 (e.g., a width along the x and / or y axes). In some embodiments, a portion of the reference layer 140 is removed up to the edge of the intermediate layer 130. In other embodiments, such portions of the reference layer 140 may be "over-etched". In other words, a portion of the intermediate layer 130 may be removed together with portions of the top electrode 180, cap region 170, fixing region 160, transition layer 150, reference layer 140 and / or intermediate layer 130.

[0066] In some embodiments, after removing at least a portion of the top electrode 180, cap region 170, fixing region 160, transition layer 150, reference layer 140, and / or intermediate layer 130, one or more oxides (e.g., auxiliary oxides, silica, etc.) or nitrides (e.g., Six Ny) can be applied to the stack (e.g., an etched magnetoresistive stack) by means of, for example, physical vapor deposition (PVD), chemical vapor deposition (CVD), other thin film processes, and / or other techniques known in this art. Figure 20 illustrates an etched magnetoresistive structure of one of the auxiliary oxide-coated (i.e., oxide-coated magnetoresistive stacks) according to one or more embodiments.

[0067] Referring again to FIG. 20, in one or more embodiments, oxide regions 190 are formed on the intermediate layer 130, reference layer 140, transition layer 150, fixing region 160, capping region 170, and / or top electrode 180. As used herein, oxide region 190 may refer to a region comprising an oxide (e.g., auxiliary oxide, silica, etc.) and / or a nitride (e.g., Six Ny). In some embodiments, the oxide-coated magnetoresistive stack may include one or more oxide regions 190 disposed above and in contact with the intermediate layer 130. Oxide regions 190 may cover the entire top surface of the substrate top electrode 180 and / or intermediate layer 130. In other embodiments, only a portion of the top surface of the intermediate layer 130 is covered by oxide regions 190. In some embodiments, oxide may be applied such that oxide regions 190 contact or completely cover the thickness of the reference layer 140, transition layer 150, fixing region 160, capping region 170, and / or top electrode 180. The oxide region 190 may conformally surround the magnetoresistive stack and cover the vertical sidewalls of one or more regions of the magnetoresistive stack (e.g., reference layer 140, transition layer 150, fixed region 160, cap region 170 and / or top electrode 180).

[0068] In some embodiments, after the oxide region 190 is formed, one or more etching processes (e.g., processes involving etching, grinding, and / or otherwise polishing one or more layers) may be performed on the oxide-coated magnetoresistive stack. For example, referring to FIG21, at least a portion of the oxide region 190, the intermediate layer 130, and / or the free region 120 may be removed from the oxide-coated magnetoresistive structure. In some embodiments, at least a portion of the free region 120 may be removed such that one or more sidewalls of the free region 120 have a tapered edge (i.e., the free region 120 includes a tapered sidewall). For example, the bottom surface of the free region 120 (e.g., the surface contacting the SH material 110) may have a diameter (e.g., a width along the x or y direction) larger than the diameter of the top surface of the free region 120 (e.g., the surface contacting the intermediate layer 130).

[0069] Referring to Figures 22A to 22C, after forming a free region 120 including a tapered sidewall, at least a portion of the intermediate layer 130, the free region 120, and / or the SH material 110 can be removed to form a stack 200 asymmetrical with respect to a longitudinal axis of the SH material 110. For example, a cross-section near the top of the stack 200 (e.g., a cross-section including the top electrode 180 and the oxide region 190) may have a smaller diameter than a cross-section near the bottom of the stack 200 (e.g., a cross-section including the free region 120). In some embodiments, the free region 120 may be "over-etched". In other words, a portion of the SH material 110 beneath the etched portion of the free region 120 may also be removed by etching.

[0070] Referring to Figure 22A, after removing at least a portion of the intermediate layer 130, free region 120, and / or SH material 110, a cross-section in the zy plane of the stack 200 is symmetrical with respect to a longitudinal axis of the stack 200. As previously described, after current 302 passes through SH material 110, spin current 303 is injected from SH material 110 into free region 120. Referring to Figure 22B, after removing at least a portion of the intermediate layer 130, free region 120, and / or SH material 110, a cross-section in the zy plane of the stack 200 is asymmetrical with respect to a longitudinal axis of the stack 200. As shown in Figure 22B, the magnetic moments 305 of free region 120 combine to form a total magnetic moment in free region 120 toward the removed portion of free region 120 (e.g., toward a sidewall that is no longer tapered). This asymmetric magnetic moment can help apply the desired magnetic properties to the stack 200 and / or advance, promote, maintain, or otherwise facilitate the transfer of spin current 303 from SH material 110 to free region 120. Although the right wall of free region 120 is shown as vertical in Figure 22B, this is an example. In other embodiments, free region 120 may still have tapered sidewalls, provided that the composite magnetic moment 305 of free region 120 is asymmetric.

[0071] The stack shape shown in Figures 22A to 22C can be formed, for example, by performing a selective angular etching on a magnetoresistive stack 200 including a free region 120 containing a tapered sidewall. Those skilled in the art will recognize that the substrate being etched is typically rotated during etching (e.g., by ion beam etching (IBE)). In some embodiments, the magnetoresistive structure is not rotated during an angular etching to remove more material on one side of the stack 200 than on an opposing side.

[0072] Referring again to the oxide-coated magnetoresistive stack shown in FIG20, a selective angular etching can be performed on the oxide-coated magnetoresistive stack to remove at least a portion of the oxide region 190. In some embodiments, the magnetoresistive structure is not rotated during the angular etching to remove more material on one side of the stack 200 than on the opposite side of the stack 200. After a portion of the oxide region 190 has been removed from the oxide-coated magnetoresistive stack, an asymmetric magnetoresistive stack 200, such as, for example, the stack 200 shown in FIG23, can be formed.

[0073] Referring again to FIG. 23, after removing at least a portion of the oxide regions 190, the magnetoresistive stack 200 may include one or more oxide regions 190 disposed above and in contact with the intermediate layer 130. The oxide regions 190 may cover the entire top surface of the substrate top electrode 180 and / or the intermediate layer 130. In other embodiments, only a portion of the top surface of the intermediate layer 130 is covered by the oxide regions 190. In some embodiments, the oxide regions 190 contact or completely cover the thickness of the reference layer 140, transition layer 150, fixing region 160, capping region 170, and / or top electrode 180. Even after removing at least a portion of the oxide regions 190, the oxide regions 190 may conformally surround the magnetoresistive stack and cover the vertical sidewalls of one or more regions of the magnetoresistive stack (e.g., reference layer 140, transition layer 150, fixing region 160, capping region 170, and / or top electrode 180).

[0074] After performing a selective angular etching on the oxide-coated magnetoresistive stack (resulting in, for example, the asymmetric structure shown in FIG. 23), at least a portion of the SH material 110, free region 120, intermediate layer 130, reference layer 140, transition layer 150, fixed region 160, cap region 170, top electrode 180, and / or cap region 190 may be removed to result in an asymmetric magnetoresistive structure, such as the asymmetric magnetoresistive structures shown in FIG. 24A to FIG. 24C. In some embodiments, at least a portion of the free region 120 may be removed such that one or more sidewalls of the free region 120 have a tapered edge (i.e., the free region 120 includes a tapered sidewall). For example, the bottom surface of the free region 120 (e.g., the surface contacting the SH material 110) may have a diameter (e.g., a width along the x or y direction) larger than the diameter of the top surface of the free region 120 (e.g., the surface contacting the intermediate layer 130).

[0075] Referring to Figures 24A to 24C, after forming a free region 120 including a tapered sidewall, the stack 200 may be asymmetrical relative to a longitudinal axis of the SH material 110. For example, a cross-section near the top of the stack 200 (e.g., a cross-section including the top electrode 180 and oxide region 190) may have a smaller diameter than a cross-section near the bottom of the stack 200 (e.g., a cross-section including the free region 120). In some embodiments, the free region 120 may be "over-etched". In other words, a portion of the SH material 110 beneath the etched portion of the free region 120 may also be removed by etching.

[0076] Referring to Figure 24A, after the formation of the free region 120 with a tapered sidewall, a cross-section in the zy plane of the stack 200 is symmetrical with respect to a longitudinal axis of the stack 200. As previously described, after the current 302 passes through the SH material 110, a spin current 303 is injected from the SH material 110 into the free region 120. Referring to Figure 24B, after the formation of the free region 120 with a tapered sidewall, a cross-section in the zy plane of the stack 200 is asymmetrical with respect to a longitudinal axis of the stack 200. As shown in Figure 24B, the magnetic moments 305 of the free region 120 combine to form a total magnetic moment in the free region 120 toward the removed portion of the free region 120 (e.g., toward a sidewall that is no longer tapered). As described above, this asymmetrical magnetic moment can help to apply the desired magnetic properties to the stack 200 and / or advance, promote, maintain, or otherwise facilitate the transfer of the spin current 303 from the SH material 110 to the free region 120. Although the right wall of free region 120 is shown to be angled relative to a vertical axis and not parallel to the right wall of intermediate layer 130, this is an example. In other embodiments, free region 120 may have one or more vertical sidewalls, provided that the composite magnetic moment 305 of free region 120 is asymmetrical.

[0077] Figure 25 is a flowchart of a method 400 for manufacturing a magnetoresistive structure 100 utilizing STT and / or SOT switching according to one or more embodiments of the present invention. Method 400 may include forming a segment of SH material 110 (step 401). Method 400 may further include forming a magnetoresistive stack 200 comprising one or more insert layers 201, 202, 203, 204, wherein each insert layer 201, 202, 203, 204 comprises an antiferromagnetic material (step 402). In some embodiments, method 400 may include applying a magnetic field to the magnetoresistive stack 200 (step 403). Method 400 may further include annealing the magnetoresistive stack 200, wherein after annealing, one or more insert layers 201, 202, 203, 204 have a magnetic moment parallel or antiparallel to the SH material segment (step 404).

[0078] Figure 26 is a flowchart of a method 500 for manufacturing a magnetoresistive structure 100 utilizing STT and / or SOT switching according to one or more embodiments of the present invention. Method 500 may include forming a magnetoresistive stack 200 comprising a dielectric layer (e.g., intermediate layer 130) and a free region 120 on a segment of SH material 110 (step 501). Method 500 may further include removing at least a portion of one or more layers of the magnetoresistive stack 200 to expose at least a portion of the dielectric layer (e.g., intermediate layer 130) and forming an etched magnetoresistive stack (step 502). In some embodiments, method 500 may include depositing an auxiliary oxide on the etched magnetoresistive stack to form an oxide region 190 (step 503). Method 500 may further include removing at least a portion of the auxiliary oxide (e.g., from oxide region 190), the dielectric layer, and the free region 120 to form a free region 120 comprising a tapered sidewall (step 504). In some instances, method 500 may further include using a selective angle etching to remove at least a portion of the free region 120 containing a tapered sidewall (step 505).

[0079] Figure 27 is a flowchart of a method 600 for manufacturing a magnetoresistive structure 100 utilizing STT and / or SOT switching according to one or more embodiments of the present invention. Method 600 may include forming a magnetoresistive stack 200 comprising a dielectric layer (e.g., intermediate layer 130) and a free region 120 on a segment of SH material 110 (step 601). Method 600 may further include removing at least a portion of one or more layers of the magnetoresistive stack 200 to expose at least a portion of the dielectric layer (e.g., intermediate layer 130) and forming an etched magnetoresistive stack (step 602). In some embodiments, method 600 may include depositing an auxiliary oxide on the etched magnetoresistive stack to form an oxide region 190 (step 603). Method 600 may further include using a selective angle etching to remove at least a portion of the auxiliary oxide (e.g., from oxide region 190) (step 604). In some instances, method 600 may further include removing at least a portion of each of the auxiliary oxide (e.g., from oxide region 190), dielectric layer (e.g., intermediate layer 130), and free region 120 to form a free region 120 including a tapered sidewall.

[0080] As mentioned above, the magnetoresistive device of the present invention, comprising one or more switching geometries described herein, can be implemented in a sensor architecture or a memory architecture (and other architectures). For example, in a memory configuration, the magnetoresistive device can be electrically connected to an access transistor and configured to be coupled or connected to various conductors capable of carrying one or more control signals, as shown in FIG28. The magnetoresistive device of the present invention can be used in any suitable application, including, for example, in a memory configuration. In such examples, the magnetoresistive device can be formed as an integrated circuit comprising a discrete memory device (e.g., shown in FIG29A) or an embedded memory device (e.g., shown in FIG29B) having logic therein, the discrete memory device and the embedded memory device each comprising an MRAM, the MRAM in one embodiment representing one or more MRAM arrays of a plurality of magnetoresistive stacks having a specific pattern according to a particular embodiment disclosed herein.

[0081] In one embodiment, 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 adjacent to at least a portion of the free region and an insert layer disposed between the spin Hall material and the top electrode, wherein the insert layer comprises an antiferromagnetic material.

[0082] Alternatively, various embodiments of the disclosed magnetoresistive device may also include one or more of the following features: the intercalation layer may include manganese; the SH material may include at least one of the following: platinum, β-tungsten, tantalum, palladium, hafnium, gold, an alloy containing gold, an alloy containing bismuth and selenium, an alloy containing copper, an alloy containing manganese, iridium, selenium, or a combination thereof; the intercalation layer may have a thickness of less than or equal to about 2.0 nanometers; the intercalation layer may be a first intercalation layer, and the device may further include: a second intercalation 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 intercalation layer, the second intercalation layer, or both are in contact with the cap region or the transition layer; and / or a third intercalation layer, which is in contact with the cap region or the transition layer.

[0083] 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 accessible to at least a portion of the magnetically free region. A cap region may be located on the opposite side of the fixed region relative to the free region. The device may include a transition layer between the intermediate layer and the fixed region, and at least one insert layer adjacent to the cap region or the transition layer, wherein the at least one insert layer comprises an antiferromagnetic material.

[0084] Alternatively, various embodiments of the disclosed magnetoresistive device may also include one or more of the following features: the intercalation layer may include manganese; the intercalation layer may further include iridium or platinum; the intercalation layer may have a thickness of less than or equal to about 2.0 nanometers; a current flowing through the SH material in a first direction can switch the free region to a first magnetic state, and a current flowing in a second direction can switch the free region to a second magnetic state; the fixed region may include a synthetic antiferromagnetic structure (SAF); the at least one intercalation layer may be a first intercalation layer, and the device may further include a second intercalation layer adjacent to the cap region or the transition layer; and / or the device may further include a reference layer between the transition layer and the dielectric layer.

[0085] In another embodiment, a method for manufacturing a magnetoresistive device is disclosed. The method may include forming a segment of an 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 an oxide (and / or nitride) to thereby form 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 to form a free region including a tapered sidewall.

[0086] Various embodiments of the disclosed method may also include one or more of the following features: a second etching step comprising removing at least a portion of the oxide region, removing at least a portion of the free region, or both; selective angular etching; 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 comprising a tapered sidewall, the magnetoresistive stack may be asymmetrical about a longitudinal axis of the magnetoresistive stack, the longitudinal axis being perpendicular to a surface of the SH material in contact with the free region.

[0087] Although various embodiments of the invention have been illustrated and described in detail, those skilled in the art will readily understand that various modifications can be made without departing from the invention.

[0088] 100: Magnetoresistive structure / stack 110: Spin Hall (SH) Materials 120: Free Zone 130: Intermediate Layer 140: Reference Layer 150: Transition Layer 160: Fixed Area 170: Cap area 180: Top electrode 190: Oxide region 200: Magnetoresistive stacking 201: First Insertion Layer 202: Second Insertion Layer 203: Third Insertion Layer 204: Fourth Insertion Layer 301: Magnetic Moment 302: Current 303: Spin Current 304: Local stray magnetic field 305: Magnetic Moment 400: Method 401: Steps 402: Steps 403: Steps 404: Steps 500: Methods 501: Steps 502: Steps 503: Steps 504: Steps 505: Steps 600: Method 601: Steps 602: Steps 603: Steps 604: Steps

Claims

1. A magnetoresistive device, comprising: One top electrode; A fixed region located below the top electrode, the fixed region having a fixed magnetic state; a cap region located above the fixed region and below the top electrode; a free region located below the fixed region, wherein the free region is configured to have a first magnetic state and a second magnetic state; a dielectric layer located between the free region and the fixed region; a transition layer located between the dielectric layer and the fixed region; and a reference layer located between the transition layer and the dielectric layer. A spin Hall (SH) material is located near at least a portion of the free region; and a first insertion layer and a second insertion layer are disposed between the SH material and the top electrode, wherein the first insertion layer 202 and the second insertion layer 201: (i) are in contact with the cap region 170 and the transition layer 150, respectively; or (ii) are in contact with opposite sides of the cap region; or (iii) are in contact with opposite sides of the transition layer, wherein each of the first insertion layer and the second insertion layer comprises an antiferromagnetic material.

2. The magnetoresistive device of claim 1, wherein at least one of the first insertion layer or the second insertion layer comprises manganese.

3. The magnetoresistive device of claim 1, wherein the SH material comprises at least one of the following: platinum, β-tungsten, tantalum, palladium, hafnium, gold, an alloy containing gold, an alloy containing bismuth and selenium, an alloy containing copper, an alloy containing manganese, iridium, selenium, or one or more combinations thereof.

4. The magnetoresistive device of claim 1, wherein at least one of the first insertion layer or the second insertion layer has a thickness of less than or equal to about 2.0 nm.

5. The magnetoresistive device of claim 1, wherein at least one of the first insert layer or the second insert layer further comprises iridium or platinum.

6. The magnetoresistive device of claim 1, wherein the fixed region comprises a synthetic antiferromagnetic structure (SAF).

7. The magnetoresistive device of claim 1, further comprising a third insert layer that contacts one of: (i) the cap region or the opposite side of the transition layer that is not in contact with the first insert layer or the second insert layer; or (ii) the transition layer; or (iii) the cap region.

8. A magnetoresistive device comprising: A fixed region having a fixed magnetic state; a free region configured to switch between a first magnetic state and a second magnetic state; a dielectric layer located between the free region and the fixed region; a spin Hall (SH) material adjacent to at least a portion of the free region; a cap region located above the fixed region; a transition layer located between the dielectric layer and the fixed region; and a first insertion layer in contact with the transition layer, wherein the first insertion layer comprises an antiferromagnetic material, the transition layer comprises a nonferromagnetic transition metal, and the transition layer is configured to assist in forming a reference layer between the dielectric layer and the first insertion layer.

9. The magnetoresistive device of claim 8, wherein the first insert layer comprises manganese.

10. The magnetoresistive device of claim 9, wherein the first insert layer further comprises iridium or platinum.

11. The magnetoresistive device of claim 10, wherein the first insertion layer has a thickness of less than or equal to about 2.0 nm.

12. The magnetoresistive device of claim 8, wherein a current flowing through the SH material in a first direction switches the free region to the first magnetic state, and wherein a current flowing in a second direction switches the free region to the second magnetic state.

13. The magnetoresistive device of claim 8, wherein the fixed region comprises a synthetic antiferromagnetic structure (SAF).

14. The magnetoresistive device of claim 8, wherein the magnetoresistive device further includes a second insert layer in contact with the cap region.

15. The magnetoresistive device of claim 8, wherein the reference layer is disposed between the transition layer and the dielectric layer.

16. A method for manufacturing a magnetoresistive device, the method comprising: This forms one segment of the SH material; A magnetoresistive stack is formed in contact with the SH material, wherein the magnetoresistive stack, from top to bottom, sequentially includes: a top electrode, a cap region, a fixed region, a transition layer, a reference layer, an intermediate layer, a dielectric layer, and a free region configured to switch between a first magnetic state and a second magnetic state, wherein the magnetoresistive stack further includes a first insertion layer disposed between the SH material and the top electrode and in contact with the cap region or the transition layer; at least a portion of one or more layers of the magnetoresistive stack is removed to form an etched magnetoresistive stack; an oxide is deposited on the etched magnetoresistive stack to form at least one oxide region; at least a portion of the oxide region is removed; And remove at least a portion of the free region to form a free region containing a conical sidewall.

17. The method of claim 16, wherein the step of removing at least a portion of one or more layers of the magnetoresistive stack to form an etched magnetoresistive stack is a first etching step; and a second etching step includes a step of removing at least a portion of the oxide region, a step of removing at least a portion of the free region, or both.

18. The method of claim 16, wherein 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 comprise a selective angular etching.

19. The method of claim 16, wherein removing at least a portion of one or more layers of the magnetoresistive stack to form the etched magnetoresistive stack includes exposing at least a portion of the dielectric layer.

20. The method of claim 16, wherein after forming a free region comprising a tapered sidewall, the magnetoresistive stack is asymmetrical about a longitudinal axis of the magnetoresistive stack, the longitudinal axis being perpendicular to a surface of the SH material in contact with the free region.

Images