Bismuth-antimony alloys as topological insulators

Abstract

The present invention relates to a SOT device, which includes a bismuth-antimony dopant element (BiSbE) alloy layer located above a substrate. The BiSbE alloy layer serves as a topological insulator. The BiSbE alloy layer contains bismuth, antimony, and a dopant element. The dopant element is a non-metallic dopant element, a metal dopant element, or a combination thereof. Examples of metal dopant elements include Ni, Co, Fe, CoFe, NiFe, NiCo, NiCu, CoCu, NiAg, CuAg, Cu, Al, Zn, Ag, Ga, In, or a combination thereof. Examples of non-metallic dopant elements include Si, P, Ge, or a combination thereof. The BiSbE alloy layer may include a plurality of BiSb thin lamellae and one or more dopant element thin lamellae. The BiSbE alloy layer has a (012) orientation.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. application No. 16 / 917,334, filed June 30, 2020, which is incorporated herein by reference in its entirety. Background Art Technical Field

[0003] Embodiments of the present disclosure generally relate to bismuth antimony (BiSb) alloys with a (012) orientation for use as topological insulators.

[0004] Description of related art

[0005] BiSb with a (012) orientation is a narrow-gap topological insulator that exhibits both a giant spin Hall effect and high electrical conductivity. BiSb has been proposed for various spin-orbit torque (SOT) applications, such as spin Hall layers in magnetoresistive random access memory (MRAM) devices and energy-assisted magnetic recording (EAMR) write heads.

[0006] However, BiSb materials have not been adopted in commercial SOT applications due to several obstacles. For example, BiSb materials have a low melting point, large particle size, significant Sb migration issues during thermal annealing due to film roughness, difficulty maintaining the (012) orientation for maximum spin Hall effect, and are generally soft and easily damaged by ion milling.

[0007] Therefore, there is a need for improved SOT devices and processes for forming BiSb layers having a (012) orientation. Summary of the Invention

[0008] Embodiments of the present disclosure generally relate to bismuth antimony (BiSb) alloys with a (012) orientation for use as topological insulators in spin-orbit torque (SOT) devices.

[0009] In one embodiment, a SOT device includes a bismuth-antimony dopant element (BiSbE) alloy layer located above a substrate. The BiSbE alloy layer includes bismuth, antimony, and a dopant element. The dopant element is a non-metallic dopant element, a metallic dopant element, or a combination thereof. Examples of metallic dopant elements include Ni, CoFe, CoFe, NiFe, NiCo, NiCu, CoCu, NiAg, CuAg, Cu, Al, Zn, Ag, Ga, In, or a combination thereof. Examples of non-metallic dopant elements include Si, P, Ge, or a combination thereof. The BiSbE alloy layer has a (012) orientation.

[0010] In another embodiment, a SOT device includes a bismuth antimony dopant element (BiSbE) alloy layer located above a substrate. The BiSbE alloy layer includes a plurality of BiSb lamellae and one or more dopant element lamellae. Each of the dopant element lamellae layers includes a non-metallic dopant element, a metal dopant element, or a combination thereof. Examples of metal dopant elements include Ni, CoFe, CoFe, NiFe, NiCo, NiCu, CoCu, NiAg, CuAg, Cu, Al, Zn, Ag, Ga, In, or a combination thereof. Examples of non-metallic dopant elements include Si, P, Ge, or a combination thereof. The BiSbE alloy layer has a (012) orientation.

[0011] In yet another embodiment, a magnetoresistive random access memory (MRAM) device includes a bismuth antimony dopant element (BiSbE) alloy layer. The BiSbE alloy layer comprises bismuth, antimony, and a metal dopant element. The metal dopant element is Ni, CoFe, CoFe, NiFe, NiCo, NiCu, CoCu, NiAg, CuAg, Cu, Al, Zn, Ag, Ga, In, or a combination thereof. The BiSbE alloy layer has a (012) orientation. The MRAM device further includes a perpendicular magnetic anisotropy (PMA) ferromagnetic layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Thus, a detailed understanding of the manner in which the above-recited features of the present disclosure are understood, a more particular description of the disclosure, the brief summary above, and the like, may be obtained by reference to the embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the drawings illustrate only typical embodiments of the disclosure and are therefore not to be considered limiting of its scope, as the disclosure may admit to other equally effective embodiments.

[0013] Figure 1A-1C is a schematic diagram of a BiSb alloy layer containing a dopant element.

[0014] Figure 2A-2B is a schematic diagram of a BiSbE alloy layer including a plurality of BiSb flake layers and including a dopant element flake layer between each of the BiSb flake layers. Figure 2C-2D is a schematic diagram of a BiSbE alloy layer including a plurality of BiSb flake layers and including dopant element flake layers at the bottom and top edges of the BiSbE alloy layer. Figure 2E-2F is a schematic diagram of a BiSbE alloy layer including a plurality of BiSb flake layers and including dopant element flake layers at the bottom edge, center, and top edge of the BiSbE alloy layer. Figure 2G-2His a schematic diagram of a BiSbE alloy layer including a plurality of BiSb flake layers and including a dopant element flake layer at a bottom edge of the BiSbE alloy layer.

[0015] Figure 3 2θ XRD scans of BiSb orientations for various stacks of BiSbE alloy layers containing the non-metallic dopant element Si are shown versus the logarithm of the intensity.

[0016] Figure 4 Shown are 2θ XRD scans of BiSb orientation for various stacks of BiSbE alloy layers containing the metal dopant element CuAgNi versus the logarithm of the intensity.

[0017] Figure 5 The TOF-SIMS net intensity of the dopant E-Cs+ clusters across the BiSbE alloy layer is shown for the dopant elements NiFe, Si, and CuAgNi.

[0018] Figure 6 Shown is a TEM Cu EELS scan across a BiSbE stack comprising a silicide capping layer, a BiSbE alloy layer containing the metal dopant CuAgNi, and a silicide seed layer.

[0019] Figure 7 Shown is the conductivity versus thickness for various BiSbE alloy layers including metal dopants.

[0020] Figure 8 Shown is the conductivity versus thickness for various BiSbE alloy layers containing non-metallic dopant elements.

[0021] Figure 9 Shown is the relationship between the concentration of the non-metallic dopant element Si and the BiSbSi grain size of the as-deposited room-temperature BiSbSi alloy, as measured by in-plane XRD patterns acquired at a 1 degree incident angle for various Si dopant element concentrations.

[0022] Figure 10 Shown is the surface roughness of the BiSbE alloy layer as a function of the atomic percent content of the non-metallic dopant element Si as determined by XRR.

[0023] Figure 11 The estimated grain size of the BiSbE alloy is shown for non-metallic dopant elements and for metallic dopant elements as a function of the estimated thickness of the BiSbE.

[0024] Figure 12 is a plot of the logarithm of the intensity of the BiSbE stacking versus the 2θ XRD out-of-plane or coupled scan.

[0025] Figure 13A is a schematic cross-sectional view of certain embodiments of a SOT device having a BiSbE alloy layer with a (012) orientation forming a SOT-based magnetoresistive random access memory (MRAM) device.

[0026] Figure 13B is a schematic cross-sectional view of certain embodiments of a SOT device having a BiSbE alloy layer with a (012) orientation forming part or component of a SOT-based energy-assisted magnetic recording (EAMR) write head for use in magnetic recording.

[0027] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. DETAILED DESCRIPTION

[0028] Hereinafter, reference is made to embodiments of the present disclosure. However, it should be understood that the present disclosure is not limited to the specifically described embodiments. On the contrary, any combination of the following features and elements (whether or not related to different embodiments) is considered to implement and practice the present disclosure. In addition, although the embodiments of the present disclosure can achieve advantages over other possible solutions and / or advantages over the prior art, whether a specific advantage is achieved by a given embodiment is not a limitation of the present disclosure. Therefore, the following aspects, features, embodiments and advantages are merely illustrative and are not considered to be elements or limitations of the appended claims unless expressly stated in the claims. Similarly, reference to "the present disclosure" should not be interpreted as a summary of any inventive subject matter disclosed herein, and should not be considered to be elements or limitations of the appended claims unless expressly stated in the claims. The use of the term "comprising" in the summary of the invention or in the specific embodiments should mean including, consisting essentially of and / or consisting of.

[0029] Embodiments of the present disclosure generally relate to bismuth-antimony (BiSb) alloys having a (012) orientation that serve as topological insulators. The BiSb alloy comprises bismuth, antimony, and a dopant element (E), and is referred to herein as a BiSbE alloy. The dopant element comprises a non-metallic dopant element, a metallic dopant element, or a combination thereof.

[0030] A BiSbE alloy layer with a (012) orientation has a large spin Hall angle effect and high electrical conductivity. Compared to BiSb materials without dopant elements, certain embodiments of the BiSbE alloy layer have a reduced grain size and lower interface roughness. Compared to BiSb materials without dopant elements, certain embodiments of the BiSbE alloy layer containing metal dopant elements have an increased melting temperature and allow the use of higher annealing temperatures while maintaining a high (012) texture. The BiSbE alloy layer with a (012) orientation can be used to form a spin-orbit torque (SOT) device, such as a spin Hall electrode layer in an MRAM device or an EAMR write head. For example, the BiSbE alloy layer is implemented as a SOT device that is annealed to set the magnetic direction of a perpendicular magnetic anisotropy (PMA) ferromagnetic layer.

[0031] Existing BiSb layers with a (012) orientation have a large spin Hall angle effect and high electrical conductivity. Table 1 shows an example of the properties of a BiSb layer with a (012) orientation compared to β-tantalum and a BiSb layer with a (001) orientation. Compared to β-tantalum (β-Ta) or a BiSb layer with a (001) orientation, a BiSb layer with a (012) orientation has similar electrical conductivity and a much larger spin Hall angle. Therefore, the relative power required to produce the spin Hall effect in BiSb (012) is lower than that of β-Ta or BiSb (001).

[0032]

[0033] Depending on the Sb content, existing BiSb materials having an Sb content of about 5 atomic % to about 22 atomic % have a melting point of about 270° C. to about 300° C. During annealing, existing BiSb materials experience high levels of undesirable Sb migration due to the high roughness of the BiSb material.

[0034] The BiSbE alloy layers of the present invention according to various embodiments disclosed herein have a high degree of (012) orientation, a large spin Hall angle effect, low interface roughness, and high electrical conductivity comparable to BiSb(012) materials without dopant elements. In certain embodiments, the BiSbE alloy layers with metal dopant elements provide for higher annealing temperatures to be used compared to BiSb materials without dopant elements.

[0035] In certain embodiments, the BiSbE alloy layer contains non-metallic dopant elements, which include Si, P, Ge, other suitable non-metallic dopant elements, or combinations thereof. In certain embodiments, the BiSbE alloy layer contains metallic dopant elements, which include Ni, Co, Fe, CoFe, NiFe, NiCo, NiCu, CoCu, NiAg, CuAg, Cu, Al, Zn, Ag, Ga, In, other suitable metallic dopant elements, or combinations thereof.

[0036] In certain embodiments, the BiSbE alloy layer contains Bi 1-x Sb x E (where 0.05 < x < 0.22) and contains from about 0.5 atomic % to about 15 atomic % of dopant element (E).

[0037] Without being bound by theory, unless explicitly set forth in the claims, it is believed that the dopant elements in the BiSb alloy layer have low solubility within the BiSb lattice while maintaining the topological insulator properties and the (012) orientation of the BiSb material. It is believed that a portion of the dopant elements enter the BiSb lattice after deposition. For example, in certain embodiments, for dopant elements deposited at room temperature, a portion of the dopant elements enter the BiSb lattice and cause the a-axis to contract by about 0.5% and the c-axis to expand from about 0.5% to about 1.0%. It is believed that a portion of the dopant elements can act as grain boundary segregants that refine the BiSb grain structure, or reach the BiSbE interface region to form a partial seed layer or a partial cap layer.

[0038] Figure 1A is a schematic top-plan view of the BiSbE alloy layer 100 at the time of deposition. The BiSbE alloy layer 100 at the time of deposition includes a plurality of BiSb thin layers 110 and one or more dopant element thin layers. The BiSbE alloy layer 100 includes BiSb grains and a layer of atoms / clusters 120 of dopant elements deposited uniformly over the BiSb grains. It is believed that the atoms / clusters 120 of the dopant element thin layer are formed uniformly over the BiSb thin layer 110.

[0039] Figure 1Bis a schematic diagram of a top plan view of the BiSbE alloy layer 100 after post-annealing. It is believed that the dopant element atoms / clusters 120 have redistributed to the grain boundaries of the BiSbE thin layer 110. Some portions of the dopant element atoms / clusters 120 remain in the BiSb lattice, while other portions of the dopant element atoms / clusters 120 reach the BiSb grain boundaries and the BiSbE interface. The portion of the dopant element that reaches the BiSb grain boundaries acts as a segregant, reducing the BiSb grain size and lowering the interfacial roughness of the BiSbE alloy layer 100. In certain embodiments, the portion of the dopant element, including the metal dopant element, that remains in the BiSb lattice increases the melting point of the BiSbE alloy layer compared to a BiSb layer without the dopant element. The portion of the dopant element that remains in the BiSb lattice allows the annealing temperature of the BiSbE alloy layer to be increased due to alloying (lattice hardening) and grain boundary segregation (grain size hardening) effects, which constrain and limit grain boundary movement at high temperatures. The BiSbE alloy layer can withstand annealing, such as annealing at about 280°C or above for three hours or longer.

[0040] Figure 1C FIG2 is a schematic diagram of a cross-sectional layer view of a BiSbE alloy layer 100 after post-annealing. It is believed that atoms / clusters 120 of the dopant element have been redistributed to the grain boundaries of the BiSbE thin layer 110, as well as to seed or cap layer interfaces, such as silicide seed or silicide cap layers. The portion of the dopant element that reaches the grain boundaries becomes segregants, which reduce or alter the grain size and lattice parameter of the BiSb grains 110 and reduce the interface roughness of the BiSbE alloy layer 100.

[0041] In certain embodiments, the interface roughness of the BiSbE alloy layer with the silicide seed layer and the silicide cap layer is about In certain embodiments, the interface roughness of the BiSbE alloy layer having the silicide seed layer and the silicide cap layer is reduced by about 100% compared to the BiSb material without the dopant element. Arrive at the appointment The use of metal interlayers between the BiSbE alloy layer and the silicide seed layer and between the BiSbE alloy layer and the silicide cap layer further reduces the interface roughness of the BiSbE alloy layer.

[0042] Compared to BiSb without dopant elements, the use of a BiSbE alloy layer enhances the (012) texture. For example, in certain embodiments, the (012) texture of the BiSbE alloy stack of a silicide seed layer, a metal interlayer, a BiSbE alloy layer, a metal interlayer, and a silicide capping layer has a rocking curve with a width of less than 11 degrees, such as from about 7 degrees to about 10 degrees. In contrast, the (012) texture of the BiSb stack without dopant elements in the stack of a silicide seed layer, a metal interlayer, a BiSb layer, a metal interlayer, and a silicide capping layer has a rocking curve with a width of about 10 degrees or more and a dual (001) and (012) texture.

[0043] In certain embodiments, the BiSbE alloy layer is formed to about Arrive at the appointment (such as about Arrive at the appointment ) thickness. In other embodiments, the BiSbE alloy layer is formed to any suitable thickness. In certain embodiments, the BiSbE alloy layer is deposited by physical vapor deposition (PVD) such as sputtering, molecular beam epitaxy, ion beam deposition, other suitable PVD processes, and combinations thereof. In certain embodiments, the SOT device includes a BiSbE alloy layer formed over any suitable layer, and any suitable layer formed over the BiSbE alloy layer.

[0044] In certain embodiments, the BiSbE alloy layer comprises a multilayer laminate of a plurality of BiSb lamellae and one or more dopant element lamellae. The BiSbE alloy multilayer laminate provides placement of the dopant element lamellae at specific regions of the BiSbE alloy layer to increase nucleation and growth of the (012) orientation, reduce interface roughness, and / or reduce grain size.

[0045] In one embodiment, the BiSbE alloy layer comprises 2 to 10 BiSb flake layers, wherein each BiSb flake layer has about Arrive at the appointment and includes 1 to 9 dopant element flake layers, wherein each dopant element flake layer has about Arrive at the appointment One or more dopant element flake layers are interspersed between the BiSb flake layers. In other embodiments, the BiSbE alloy layer includes any suitable number of BiSb flake layers, each BiSb flake layer being formed to any suitable thickness, and includes any suitable number of dopant element flake layers, each dopant element flake layer being formed to any suitable thickness.

[0046] Figure 2ASchematic diagram of the deposition of a BiSbE alloy layer 200 including six BiSb flake layers 210 and five dopant element flake layers 220. The dopant element flake layers 220 have been deposited between each of the BiSb flake layers 210. The dopant element flake layers 220 have been deposited throughout the BiSbE alloy layer 200. Figure 2B FIG. 2 is a schematic diagram illustrating the distribution of dopant elements within the BiSb thin layer 210 of the BiSbE alloy layer 200 as deposited or after annealing. The dopant element is distributed into each thin layer in the BiSb thin layer 210 .

[0047] Figure 2C Schematic diagram of the deposition of a BiSbE alloy layer 200 including six BiSb lamellae 210 and four dopant element lamellae 220. The BiSbE alloy layer 200 can also be viewed as two thin BiSb lamellae 210 at the bottom edge, two thin BiSb lamellae 210 at the top edge, and one thick BiSb lamellae 210T at the center, with the dopant element lamellae 220 between them. The dopant element lamellae 220 has been deposited at the bottom and top edges of the BiSbE alloy layer 200, rather than at the center of the BiSbE alloy layer 200. Figure 2D Schematic diagram of the distribution of dopant elements within the BiSb thin plate layer 210 of the BiSbE alloy layer 200 as deposited or after annealing. The dopant elements are distributed at the bottom edge and the top edge of the BiSbE alloy layer 200.

[0048] Figure 2E Schematic diagram of the deposition of a BiSbE alloy layer 200 comprising six BiSb flake layers 210 and three dopant element flake layers 220. The BiSbE alloy layer 200 can also be viewed as one thin BiSb flake layer 210 at the bottom edge, one thin BiSb flake layer 210 at the top edge, and two thick BiSb flake layers 210T in the center, with dopant element flake layers 220 between them. The dopant element flake layers 220 are deposited every other BiSb flake layer 210. The dopant element flake layers 220 are deposited at the bottom edge, center, and top edge of the BiSbE alloy layer 200. Figure 2F FIG. 2 is a schematic diagram illustrating the distribution of dopant elements within the BiSb thin plate layer 210 of the BiSbE alloy layer 200 as deposited or after annealing. The dopant elements are distributed at the bottom edge, center, and top edge of the BiSbE alloy layer 200 .

[0049] Figure 2GSchematic diagram of the deposition of a BiSbE alloy layer 200 including six BiSb lamellae 210 and three dopant element lamellae 220. The BiSbE alloy layer 200 can be viewed as three thin BiSb lamellae 210 at the bottom edge and one thick BiSb lamellae 210T at the top edge, with the dopant element lamellae 220 between them. The dopant element lamellae 220 has been deposited at the bottom edge of the BiSbE alloy layer 200, rather than at the top edge. Figure 2H Schematic diagram of the distribution of dopant elements within the BiSb thin plate layer 210 of the BiSbE alloy layer 200 as deposited or after annealing. The dopant elements are distributed at the bottom edge of the BiSbE alloy layer 200.

[0050] Figure 13A is a schematic cross-sectional view of certain embodiments of a SOT device 10 having a BiSbE alloy layer 50 with a (012) orientation forming a SOT-based magnetoresistive random access memory (MRAM) device.

[0051] A BiSbE alloy layer 50 having a (012) orientation is formed over a substrate 20 (such as a silicon substrate, an alumina substrate, or other suitable substrate). A seed layer 30 is deposited over the substrate 20. The seed layer 30 includes a silicide layer 32 or other suitable seed layer. In certain embodiments, the silicide layer 32 comprises NiSi, NiFeSi, NiFeTaSi, NiCuSi, CoSi, CoFeSi, CoFeTaSi, CoCuSi, or a combination thereof. In certain embodiments, the seed layer 30 further includes a surface control layer 40 located between the silicide layer 32 and the BiSbE alloy layer 50. In certain embodiments, the surface control layer 40 comprises NiFe, NiFeTa, NiTa, NiW, NiFeW, NiCu, NiFeCu, CoTa, CoFeTa, NiCoTa, Co, CoM, CoNiM, CoNi, NiSi, CoSi, NiCoSi, Cu, CuAg, CuAgM, CuM, or combinations thereof, where M is Fe, Cu, Co, Ta, Ag, Ni, Mn, Cr, V, Ti, or Si.

[0052] In certain embodiments, interlayer 70 is deposited over BiSbE alloy layer 50. Interlayer 70 includes a silicide layer 72. In certain embodiments, silicide layer 72 includes NiSi, FeSi, CoSi, NiCuSi, NiFeTaSi, CoFeSi, CoCuSi, or a combination thereof. In certain embodiments, interlayer 70 further includes a surface control layer 71 located between BiSbE alloy layer 50 and silicide layer 72. Surface control layer 71 includes Cu, Ni, NiFe, Co, or a combination thereof.

[0053] A free perpendicular magnetic anisotropy (PMA) layer 80 is formed over the interlayer 70. For example, the free PMA layer 80 may include one or more stacks of Co / Pt, Co / Pd, Co / Ni, CoFeB, FePt, or other PMA-inducing layers, or combinations thereof. An insulating layer 84, such as an MgO layer, is formed over the free PMA layer 80. A reference PMA layer 88 is formed over the insulating layer 84. The reference PMA layer 88 may include one or more stacks of Co / Pt, Co / Pd, Co / Ni, CoFeB, FePt, or other PMA-inducing layers, or combinations thereof. The reference PMA layer 88 may include one or more synthetic antiferromagnetic (SAF) pinning structures. A capping layer 92 may be formed over the reference PMA layer 88. The capping layer 92 includes NiFe, SiN, Si, NiFeTa, NiTa, Pt, Co, Cu, Ni, NiCu, CoCu, Ru, Ta, Cr, Au, Rh, CoFe, CoFeB, other non-magnetic materials, other magnetic materials, and combinations thereof. The magnetic orientation of the reference PMA layer 88 can be set by annealing at a temperature of approximately 270°C or higher for two hours or longer. In certain embodiments, the BiSbE alloy layer 50 includes a metal dopant element. The metal dopant element of the BiSbE alloy layer 50 helps maintain low interfacial roughness of the BiSbE alloy layer 50 after annealing and contributes to the manufacturability, performance, and / or lifetime of the MRAM device. Compared to a BiSb material without the dopant element, the BiSbE alloy layer 50 including the metal dopant element exhibits reduced Sb migration after post-annealing.

[0054] Multiple SOT devices 10 can be configured together as part of a memory cell array, where the BiSbE alloy layer 50 is the spin-track material electrode. A top electrode (not shown) can be disposed above the reference PMA layer 88. Each memory cell can be part of a two-terminal device or a three-terminal device. The spin-track material electrode and the top electrode can serve as bit lines, word lines, read word lines, write word lines, and combinations thereof. The memory cell array can be implemented as a cross-point array or other architectures.

[0055] Figure 13B is a schematic cross-sectional view of certain embodiments of a SOT device 10 having a BiSbE alloy layer 50 with a (012) orientation forming part or component of a SOT-based EAMR write head for use in magnetic recording.

[0056] A BiSbE alloy layer 50 having a (012) orientation is formed over a substrate 20 (such as a silicon substrate, an alumina substrate, or other suitable substrate). A seed layer 30 is deposited over the substrate 20. The seed layer 30 includes a silicide layer 32 or other suitable seed layer. In certain embodiments, the silicide layer 32 comprises NiSi, NiFeSi, NiFeTaSi, NiCuSi, CoSi, CoFeSi, CoFeTaSi, CoCuSi, or a combination thereof. In certain embodiments, the seed layer 30 further includes a surface control layer 40 located between the silicide layer 32 and the BiSbE alloy layer 50. In certain embodiments, the surface control layer 40 comprises NiFe, NiFeTa, NiTa, NiW, NiFeW, NiCu, NiFeCu, CoTa, CoFeTa, NiCoTa, Co, CoM, CoNiM, CoNi, NiSi, CoSi, NiCoSi, Cu, CuAg, CuAgM, CuM, or combinations thereof, where M is Fe, Cu, Co, Ta, Ag, Ni, Mn, Cr, V, Ti, or Si.

[0057] In certain embodiments, interlayer 70 is deposited over BiSbE alloy layer 50. Interlayer 70 includes a silicide layer 72. In certain embodiments, silicide layer 72 includes NiSi, FeSi, CoSi, NiCuSi, NiFeTaSi, CoFeSi, CoCuSi, or a combination thereof. In certain embodiments, interlayer 70 further includes a surface control layer 71 located between BiSbE alloy layer 50 and silicide layer 72. Surface control layer 71 includes Cu, Ni, NiFe, Co, or a combination thereof.

[0058] A spin torque layer (STL) 60 is formed above the interlayer 70. The STL 60 comprises a ferromagnetic material, such as one or more layers of CoFe, CoIr, NiFe, and CoFeM, where M=B, Ta, Re, or Ir. A charge current flowing through the BiSbE alloy layer 50, which serves as a spin Hall layer, generates a spin current in the BiSbE layer 50. Spin-orbit coupling between the BiSbE alloy layer 50 and the spin torque layer (STL) 60 induces switching or precession of the magnetization of the STL 60 through spin-orbit coupling of the spin current from the BiSbE alloy layer 50. The switching or precession of the magnetization of the STL 60 can generate an auxiliary DC field for the write field from the main pole of a write head used in magnetic recording. Compared to microwave-assisted magnetic recording (MAMR) elements based on spin transfer torque (STT), SOT-based EAMR elements have significantly higher power efficiency. In certain embodiments, the BiSbE alloy layer 50 comprises a metal dopant element or a non-metal dopant element. For example, if the SOT-based EAMR write head is not annealed, a BiSbE alloy layer 50 containing a non-metallic dopant element may be used because degradation of the interface roughness due to post-annealing is avoided.

[0059] The SOT device includes a bismuth antimony dopant element (BiSbE) alloy layer located above a substrate. The BiSbE alloy layer is used as a topological insulator, such as for a SOT-based MRAM device or for a SOT-based EAMR write head. The BiSbE alloy layer contains bismuth, antimony, and a dopant element. The dopant element can be a non-metallic dopant element, the non-metallic dopant element including Si, P, Ge, or a combination thereof; a metal dopant element including Ni, Co, Fe, CoFe, NiFe, Cu, Al, Zn, Ag, Ga, In, or a combination thereof; or a combination of a non-metallic dopant element and a metal dopant element. The BiSbE alloy layer may include a plurality of BiSb thin plate layers and one or more dopant element thin plate layers. The BiSbE alloy layer has a (012) orientation. In certain embodiments, the BiSbE alloy layer has a higher annealing temperature, a stronger (012) texture, a smaller grain size, and / or a lower surface roughness than a BiSb material without a dopant element.

[0060] In one embodiment, a SOT device includes a bismuth-antimony dopant element (BiSbE) alloy layer located above a substrate. The BiSbE alloy layer includes bismuth, antimony, and a dopant element. The dopant element is a non-metallic dopant element, a metal dopant element, or a combination thereof. Examples of metal dopant elements include Ni, Co, Fe, CoFe, NiFe, NiCo, NiCu, CoCu, NiAg, CuAg, Cu, Al, Zn, Ag, Ga, In, or a combination thereof. Examples of non-metallic dopant elements include Si, P, Ge, or a combination thereof. The BiSbE alloy layer has a (012) orientation.

[0061] In another embodiment, a SOT device includes a bismuth antimony dopant element (BiSbE) alloy layer located above a substrate. The BiSbE alloy layer includes a plurality of BiSb lamellae and one or more dopant element lamellae. Each of the dopant element lamellae layers includes a non-metallic dopant element, a metal dopant element, and combinations thereof. Examples of metal dopant elements include Ni, Co, Fe, CoFe, NiFe, NiCo, NiCu, CoCu, NiAg, CuAg, Cu, Al, Zn, Ag, Ga, In, or combinations thereof. Examples of non-metallic dopant elements include Si, P, Ge, or combinations thereof. The BiSbE alloy layer has a (012) orientation.

[0062] In yet another embodiment, a magnetoresistive random access memory (MRAM) device includes a bismuth antimony dopant element (BiSbE) alloy layer. The BiSbE alloy layer comprises bismuth, antimony, and a metal dopant element. The metal dopant element is Ni, Co, Fe, CoFe, NiFe, NiCo, NiCu, CoCu, NiAg, CuAg, Cu, Al, Zn, Ag, Ga, In, or a combination thereof. The BiSbE alloy layer has a (012) orientation. The MRAM device further includes a perpendicular magnetic anisotropy (PMA) ferromagnetic layer.

[0063] Example

[0064] The following is shown in Figure 1, Figure 2A-2H or Figures 13A-13B

[0026] The present invention provides examples of various embodiments of BiSbE alloy layers 50, 100, 200, other SOT devices, and variations thereof. These examples are not intended to limit the scope of the claims unless explicitly stated in the claims.

[0065] Example 1

[0066] Figure 32θ XRD scans of BiSb orientation versus the logarithm of intensity for various stacks 310-360 of BiSbE alloy layers including the non-metallic dopant element Si are shown. Each of the stacks 310-360 includes a BiSbE alloy layer formed to approximately The thickness of the NiFeCu-silicide layer and the seed layer are formed to be about A copper alloy (CuAgNi) layer of thickness is formed to be approximately The BiSbE alloy layer is formed to a thickness of about The thickness of the NiFe-silicide layer is formed into a sandwich as The BiSbSi alloy layer includes a plurality of BiSb thin flake layers and a plurality of Si thin flake layers, wherein the dopant element includes Si. Each of the BiSb thin flake layers contains approximately 90 atomic % of Bi and approximately 10 atomic % of Sb.

[0067] By depositing six BiSb flake layers (where each BiSb flake layer is deposited to about thickness) and by depositing three Si thin layers (where each Si thin layer is deposited to about A BiSbE alloy layer of the stack 310 is formed by depositing a Si thin layer in the order of BiSb-BiSb-BiSb-Si-BiSb-Si-BiSb-Si-BiSb (BBBSBSBSB) at the top edge of the BiSbE alloy layer.

[0068] By depositing six BiSb flake layers (where each BiSb flake layer is deposited to about thickness) and by depositing three Si thin layers (where each Si thin layer is deposited to about A BiSbE alloy layer stack 320 is formed by depositing a Si thin layer in the order of BiSb-BiSb-Si-BiSb-Si-BiSb-Si-BiSb-BiSb (BBSBSBSBB) at the center of the BiSbE alloy layer.

[0069] By depositing six BiSb flake layers (where each BiSb flake layer is deposited to about thickness) and by depositing three Si thin layers (where each Si thin layer is deposited to about A BiSbE alloy layer of the stack 330 is formed by depositing a Si thin layer in the order of BiSb-Si-BiSb-Si-BiSb-Si-BiSb-BiSb-BiSb (BSBSBSBBB) at the bottom edge of the BiSbE alloy layer.

[0070] By depositing six BiSb flake layers (where each BiSb flake layer is deposited to about thickness) and by depositing three Si thin layers (where each Si thin layer is deposited to about The BiSbE alloy layer stack 340 is formed by stacking the Si thin layer in the BiSbE alloy layer in the order of BiSb-Si-BiSb-BiSb-Si-BiSb-BiSb-Si-BiSb (BSBBSBBSB).

[0071] By depositing six BiSb flake layers (where each BiSb flake layer is deposited to about and by depositing four Si thin layers (where each Si thin layer is deposited to a thickness of about The BiSbE alloy layer stack 350 is formed by depositing Si thin sheets in the order of BiSb-Si-BiSb-Si-BiSb-Si-BiSb-Si-BiSb-Si-BiSb (BSBSBBSBSB) at the bottom and top edges of the BiSbE alloy layer.

[0072] By depositing six BiSb flake layers (where each BiSb flake layer is deposited to about thickness) and by depositing five Si thin layers (where each Si thin layer is deposited to about The BiSbE alloy layer stack 360 is formed by depositing Si thin sheet layers in the order of BiSb-Si-BiSb-Si-BiSb-Si-BiSb-Si-BiSb-Si-BiSb (BSBSBSBSBSB) throughout the BiSbE alloy layer.

[0073] Stack 310 with a top edge distribution of the dopant element Si and stack 320 with a center distribution of the dopant element Si do not promote a strong BiSbSi(012) orientation. Stack 330 with a bottom edge distribution of the dopant element Si, stack 340 with a modulated distribution of the dopant element Si, stack 350 with both bottom and top edge distributions of the dopant element Si, and stack 360 with a distribution of the dopant element Si throughout the BiSbE alloy layer promote a strong BiSbSi(012) orientation.

[0074] Example 2

[0075] Figure 42θ XRD scans of BiSb orientation versus the logarithm of intensity for various stacks 410-460 of BiSbE alloy layers comprising the metal dopant element CuAgNi are shown. The BiSbE alloy layers include a plurality of BiSb lamellae and a plurality of lamellae of the metal dopant element CuAgNi. Each of the BiSb lamellae includes approximately 90 atomic % Bi and approximately 10 atomic % Sb. Each of the stacks 410-460 includes a BiSb lamellae formed into approximately The seed layer of NiFeCu-silicide layer is formed to a thickness of about The thickness of the BiSbE alloy layer is formed to be about The thickness of the NiFe-silicide layer is formed into a sandwich as The thickness of the SiN cap layer is .

[0076] By depositing six BiSb flake layers (where each BiSb flake layer is deposited to about thickness) and by depositing three CuAgNi thin layers (wherein each CuAgNi thin layer is deposited to about A BiSbE alloy layer of the stack 410 is formed by depositing a CuAgNi thin layer in the order of BiSb-BiSb-BiSb-CuAgNi-BiSb-CuAgNi-BiSb-CuAgNi-BiSb (BBBCBCBB) at the top edge of the BiSbE alloy layer.

[0077] By depositing six BiSb flake layers (where each BiSb flake layer is deposited to about thickness) and by depositing three CuAgNi thin layers (wherein each CuAgNi thin layer is deposited to about A BiSbE alloy layer of the stack 420 is formed by depositing a CuAgNi thin sheet layer in the order of BiSb-BiSb-CuAgNi-BiSb-CuAgNi-BiSb-CuAgNi-BiSb-BiSb (BBCBCBCBB) at the center of the BiSbE alloy layer.

[0078] By depositing six BiSb flake layers (where each BiSb flake layer is deposited to about thickness) and by depositing three CuAgNi thin layers (wherein each CuAgNi thin layer is deposited to about A BiSbE alloy layer of the stack 430 is formed by depositing a CuAgNi thin sheet layer in the order of BiSb-CuAgNi-BiSb-CuAgNi-BiSb-CuAgNi-BiSb-BiSb-BiSb (BCBCBCBBB) at the bottom edge of the BiSbE alloy layer.

[0079] By depositing six BiSb flake layers (where each BiSb flake layer is deposited to about thickness) and by depositing three CuAgNi thin layers (wherein each CuAgNi thin layer is deposited to about The BiSbE alloy layer of the stack 440 is formed by stacking the CuAgNi thin sheet layer in the BiSbE alloy layer in the order of BiSb-CuAgNi-BiSb-BiSb-CuAgNi-BiSb-BiSb-CuAgNi-BiSb (BCBBCBBCB).

[0080] By depositing six BiSb flake layers (where each BiSb flake layer is deposited to about thickness) and by depositing four CuAgNi thin layers (wherein each CuAgNi thin layer is deposited to about The BiSbE alloy layer stack 450 is formed by depositing CuAgNi thin sheets in the order of BiSb-CuAgNi-BiSb-CuAgNi-BiSb-CuAgNi-BiSb-CuAgNi-BiSb-CuAgNi-BiSb (BCBCBB-CBCB) at the bottom and top edges of the BiSbE alloy layer.

[0081] By depositing six BiSb flake layers (where each BiSb flake layer is deposited to about thickness) and by depositing five CuAgNi thin layers (wherein each CuAgNi thin layer is deposited to about The BiSbE alloy layer of the stack 460 is formed by depositing CuAgNi thin sheets in the order of BiSb-CuAgNi-BiSb-CuAgNi-BiSb-CuAgNi-BiSb-CuAgNi-BiSb-CuAgNi-BiSb (BCBCBCBCBCB) throughout the BiSbE alloy layer.

[0082] Stack 410 with a top edge distribution of CuAgNi, stack 420 with a center distribution of CuAgNi, and stack 440 with a modulated distribution of CuAgNi do not promote a strong BiSbE (012) orientation. Stack 430 with a bottom edge distribution of CuAgNi, stack 450 with a bottom and top edge distribution of CuAgNi, and stack 460 with a distribution of CuAgNi throughout the BiSbE alloy layer promote a strong BiSbE (012) orientation.

[0083] Example 3

[0084] Figure 5A graph showing the TOF-SIMS net intensity of the dopant E-Cs+ clusters across the BiSbE alloy layer as a function of sputtering time in seconds for the dopant elements NiFe, Si, and CuAgNi. BiSbE sample 510 has an atomic percentage content of the dopant element silicon of approximately 17%, BiSbE sample 520 has an atomic percentage content of the dopant element CuAgNi of approximately 14%, and BiSbE sample 530 has an atomic percentage content of the dopant element NiFe of approximately 14%. BiSbE sample 510 is formed with a modulated distribution of the Si dopant element. BiSbE sample 520 is formed with an edge distribution of the CuAgNi dopant element. BiSbE sample 530 is formed with an edge distribution of the NiFe dopant element. The net intensity is the absolute intensity of the E-Cs+ clusters of BiSbE minus the intensity of the E-Cs+ clusters of BiSbE without the dopant element. Each of samples 510-530 includes approximately NiFeCu silicide seed layer, about Cu, about NiFe, about Cu, and about Cu, Si and The positions of the centers of the NiFeCu silicide seed layer, the NiFeCu silicide cap layer, and the BiSbE alloy layer are indicated by vertical black dashed lines.

[0085] Figure 5 This shows that a portion of the dopant element is pushed out of the BiSbE alloy layer. Figure 5 A non-zero net TOF-SIMS intensity is shown inside the BiSbE alloy layer, indicating that a portion of the dopant element remains in the BiSbE lattice after deposition.

[0086] Example 4

[0087] Figure 6 A TEM Cu EELS scan is shown across a BiSbE stack comprising a silicide capping layer, a BiSbE alloy layer containing a metal dopant CuAgNi, and a silicide seed layer. The BiSbE alloy layer contains the metal dopant CuAgNi at a concentration of approximately 6 atomic percent. The metal dopant CuAgNi contains Ag at a concentration of approximately 5 atomic percent and Ni at a concentration of approximately 10 atomic percent. The BiSbE stack comprises approximately NiFeCu silicide seed layer, about Cu, about BiSbE alloy layer, about NiFeCu silicide cap layer and about SiN layer.

[0088] The BiSbE alloy layer includes a metal dopant element located at the center of the BiSbE alloy layer, which is higher toward the interface for both room temperature and after post-annealing at approximately 280°C for 3 hours. A portion of the CuAgNi dopant element leaves the BiSb lattice, and even after post-annealing near the melting point of the BiSbE alloy layer, a portion of the CuAgNi dopant element remains in the BiSb lattice.

[0089] A portion of the dopant element remains in the lattice after near melting. It is believed that upon annealing, the BiSbE lattice relaxes the lattice parameters, with a portion of the dopant element residing within the BiSbE lattice to form an alloy, while a portion diffuses to the interlayer interfaces or grain boundaries.

[0090] Example 5

[0091] Figure 7 The as-deposited conductivity of the BiSbE alloy layers 710-750 containing metal dopants is shown as a function of thickness as measured by XRR / XRF. Each of the BiSbE alloy layers 710-750 is formed on a substrate having a thickness of approximately The surface of the Si seed layer was covered with a thickness of 1000 nm. The conductivity (1 / resistance) was measured using a four-point probe. The fitting curve showed a 2-resistor model for the surface conductive layer and the bulk conductive layer, and was fitted with an "A+B / thickness model".

[0092] BiSb layer 710 is a pure BiSb layer without dopant elements. BiSbE alloy layer 720 comprises BiSbCu with a Cu content of approximately 10 atomic percent. BiSbE alloy layer 730 comprises BiSbCu with a Cu content of approximately 14 atomic percent. BiSbE alloy layer 740 comprises BiSbCu with a Cu content of approximately 20 atomic percent. BiSbE alloy layer 750 comprises BiSb-NiFe with a NiFe content of approximately 10 atomic percent.

[0093] The BiSbE alloy layers 720, 730, 750 exhibit good topological insulator properties similar to the reference BiSb layer 710. The BiSbE alloy layer 740 exhibits bulk conduction rather than topological insulator properties.

[0094] Example 6

[0095] Figure 8The relationship between the as-deposited conductivity of various BiSbE alloy layers 820-860 containing the non-metallic dopant element Si and their thickness as measured by XRR / XRF is shown. The thickness of each of the BiSbE alloy layers 820-860 was measured by XRR and was formed on a substrate having a thickness of about The surface of the Si seed layer was covered with a thickness of 1000 nm. The conductivity (1 / resistance) was measured using a four-point probe. The fitting curve showed a 2-resistor model for the surface conductive layer and the bulk conductive layer, and was fitted with an "A+B / thickness model".

[0096] BiSb alloy layer 810 includes BiSb as a reference layer. BiSbE alloy layer 820 includes BiSbSi with a Si content of approximately 4 atomic percent. BiSbE alloy layer 830 includes BiSbSi with a Si content of approximately 5 atomic percent. BiSbE alloy layer 840 includes BiSbSi with a Si content of approximately 9 atomic percent. BiSbE alloy layer 850 includes BiSbSi with a Si content of approximately 13 atomic percent. BiSbE alloy layer 860 includes BiSbSi with a Si content of approximately 15 atomic percent.

[0097] The BiSbE alloy layers 820-860 show good topological insulator properties after deposition similar to the BiSb reference layer 810. The BiSbE alloy layers comprising BiSbSi with a Si atomic percentage content of 0% to about 15% show good topological insulator properties.

[0098] Example 7

[0099] Figure 9 The relationship between the Si dopant element concentration of the BiSbSi alloy and the BiSbSi grain size is shown, as measured by in-plane XRD patterns acquired at an incident angle of 1 degree for various BiSbSi alloy layers. Each of the BiSbSi alloy layers is formed on a substrate having a thickness of approximately A Si seed layer having a thickness of about The BiSbSi alloy layer is formed above a BiSbSi alloy layer having a thickness of 100 nm. The BiSbSi alloy layer shows a large grain size reduction trend as the Si atomic percentage increases from 0% to about 10%. The BiSbSi alloy layer shows a small grain size reduction trend as the Si atomic percentage increases from above 10%. Although the grain size of the BiSbSi alloy with a Si content of about 10 atomic% is greatly reduced compared to a BiSb material without a dopant element, further increasing the Si atomic percentage content above 10% produces only a small additional reduction in grain size.

[0100] Example 8

[0101] Figure 10 The surface roughness of the BiSbE alloy layers 610, 620 as a function of the atomic percent content of the non-metallic dopant element Si as determined by XRR is shown.

[0102] Each of the BiSbE alloy layers is formed on a substrate having approximately A Si seed layer having a thickness of about Each of the BiSbE alloy layers is deposited to a thickness of about The BiSbE alloy layer 610 includes BiSbSi with varying silicon atomic percentages. The BiSbE alloy layer 620 includes BiSbCu with varying copper atomic percentages.

[0103] Figure 10 The results show that dopant elements reduce interface roughness compared to BiSb layers without the dopant element. BiSbE alloy layers containing dopant elements ranging from approximately 3 to 12 atomic percent produce a significant reduction in surface roughness compared to BiSb materials without the dopant element. BiSbE alloy layers containing dopant elements greater than 12 atomic percent have comparable interface roughness to BiSb materials without the dopant element.

[0104] Example 9

[0105] Figure 11 Estimated grain size of BiSbE alloys from in-plane XRD patterns acquired at an angle of incidence of approximately 1 degree for the non-metallic dopant element Si, the metallic dopant element Cu, and the metallic dopant element NiFe, compared to BiSb without the dopant element, is shown as a function of the estimated BiSbE thickness obtained by XRD. The graphs provide the estimated concentration of the dopant element deposited into the film. BiSb layer 1110 comprises BiSb without the dopant element. BiSbE alloy layer 1120 comprises Si as the dopant element at approximately 5 atomic percent. BiSbE alloy layer 1130 comprises Cu as the dopant element at approximately 10 atomic percent. BiSbE alloy layer 1140 comprises Cu as the dopant element at approximately 6 atomic percent, which was annealed at approximately 280°C for 3 hours. BiSbE alloy layer 1150 comprises NiFe as the dopant element at approximately 10 atomic percent. For all BiSbE alloy thicknesses, the dopant element reduces grain size.

[0106] Example 10

[0107] Figure 12Graphs showing the logarithm of the intensity versus 2θ XRD out-of-plane or coupled scans for BiSbE stacks 1210 and 1220. The BiSbE alloy layer includes a CuAgNi metal dopant at approximately 6 atomic percent. The CuAgNi metal dopant includes approximately 5 atomic percent Ag and approximately 10 atomic percent Ni. The BiSbE alloy layer is formed by depositing six BiSb flake layers and four CuAgNi flake layers. The CuAgNi flake layers are deposited at the bottom and top edges of the BiSbE alloy layer in the order BiSb-CuAgNi-BiSb-CuAgNi-BiSb-CuAgNi-BiSb-CuAgNi-BiSb-CuAgNi-BiSb (BCBCBBCBCB).

[0108] Each of the stacks 1210, 1220 includes a plurality of stacks formed to approximately The thickness of the NiFeCu-silicide layer is formed to be about The copper layer is formed to a thickness of about The thickness of the BiSbE alloy layer is formed to be about The thickness of the NiFeCu-silicide layer is formed to be about The BiSbE stack 1210 is before annealing. The BiSbE stack 1220 is after annealing at about 280°C near the melting point of BiSb for about 3 hours. The BiSbE stacks 1210 and 1220 both show a strong (012) texture before and after annealing. The BiSbE stack 1220 shows a strong (012) texture with a rocking curve of about 11 degrees or less (such as 7 to 11 degrees) even after annealing near the melting point of BiSb. XRR measurements of the BiSbE stack 1220 after annealing show a strong (012) texture of about 11 degrees or less (such as 7 to 11 degrees). or less low surface roughness.

[0109] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be envisaged without departing from the basic scope thereof, and the scope of the disclosure is determined by the claims that follow.

Claims

1. A spin-orbit torque (SOT) device, comprising: substrate; and a bismuth antimony dopant element (BiSbE) alloy layer, the BiSbE alloy layer being located above the substrate, the BiSbE alloy layer having a (012) orientation, the BiSbE alloy layer comprising, bismuth; antimony; and One or more dopant element flake layers located at least at a top edge of the BiSbE alloy layer, each of the one or more dopant element flake layers comprising a dopant element selected from the group consisting of a non-metallic dopant element, a metallic dopant element, and combinations thereof.

2. The SOT device of claim 1 , wherein the dopant element is the metal dopant element selected from the group consisting of Ni, Co, Fe, CoFe, NiFe, NiCo, NiCu, CoCu, NiAg, CuAg, Cu, Al, Zn, Ag, Ga, In, and combinations thereof. 3 . The SOT device of claim 1 , wherein the dopant element is the non-metallic dopant element selected from the group consisting of Si, P, Ge, and combinations thereof. 4 . The SOT device according to claim 1 , wherein the BiSbE alloy layer contains 0.5 atomic % to 15 atomic % of the dopant element.

5. The SOT device according to claim 1, wherein the BiSbE alloy layer comprises Bi 1-x Sb x E, where x is 0.05 <x<0.22。 6. The SOT device according to claim 1, wherein the BiSbE alloy layer is formed as arrive thickness. 7 . The SOT device of claim 1 , wherein the BiSbE alloy layer further comprises the one or more dopant element flake layers throughout the BiSbE alloy layer.

8. A SOT MRAM device comprising the SOT device according to claim 1, wherein the BiSbE alloy layer is a spin-orbit material electrode close to a free perpendicular magnetic anisotropic ferromagnetic layer.

9. A SOT-based energy-assisted magnetic recording (EAMR) write head, the write head comprising the SOT device according to claim 1, wherein the BiSbE alloy layer is proximate to a spin torque layer.

10. A spin-orbit torque (SOT) device, comprising: substrate; and a bismuth antimony dopant element (BiSbE) alloy layer, the BiSbE alloy layer being located above the substrate, the BiSbE alloy layer having a (012) orientation, the BiSbE alloy layer comprising, a plurality of BiSb flake layers; and One or more dopant element flake layers, each of the dopant element flake layers comprising a material selected from the group consisting of non-metallic dopant elements, metallic dopant elements, and combinations thereof, wherein the one or more dopant element flake layers are located at a bottom edge of the BiSbE alloy layer and throughout the BiSbE alloy layer.

11. The SOT device of claim 10 , wherein each of the dopant element flake layers comprises the metal dopant element selected from the group consisting of Ni, Co, Fe, CoFe, NiFe, NiCo, NiCu, CoCu, NiAg, CuAg, Cu, Al, Zn, Ag, Ga, In, and combinations thereof. 12 . The SOT device of claim 10 , wherein each of the dopant element thin sheet layers comprises the non-metallic dopant element selected from the group consisting of Si, P, Ge, and combinations thereof. 13 . The SOT device of claim 10 , wherein the BiSbE alloy layer further comprises the one or more dopant element flake layers located at a top edge of the BiSbE alloy layer.

14. The SOT device of claim 10, wherein the BiSbE alloy layer further comprises the one or more dopant element flake layers modulated in the BiSbE alloy layer.

15. The SOT device according to claim 10, wherein the BiSbE alloy layer comprises Bi 1-x Sb x E, where x is 0.05 <x<0.22。 16 . A SOT MRAM device comprising the SOT device according to claim 10 , wherein the BiSbE alloy layer is a spin-orbit material electrode close to a free perpendicular magnetic anisotropic ferromagnetic layer.

17. A SOT-based energy-assisted magnetic recording (EAMR) write head comprising the SOT device according to claim 10, wherein the BiSbE alloy layer is proximate to a spin torque layer.

18. A magnetoresistive random access memory (MRAM) device, the MRAM device comprising: a bismuth antimony dopant element (BiSbE) alloy layer, the BiSbE alloy layer having a (012) orientation, the BiSbE alloy layer comprising, bismuth; antimony; and one or more dopant element lamellae throughout the BiSbE alloy layer, each of the one or more dopant element lamellae comprising a metal dopant element selected from the group consisting of Ni, Co, Fe, CoFe, NiFe, NiCo, NiCu, CoCu, NiAg, CuAg, Cu, Al, Zn, Ag, Ga, In, and combinations thereof; and Perpendicular magnetic anisotropy (PMA) ferromagnetic layer.

19. The MRAM device of claim 18, wherein the BiSbE alloy layer comprises: A plurality of BiSb flake layers, wherein the plurality of BiSb flake layers contain the bismuth and the antimony. 20 . The MRAM device of claim 19 , wherein the BiSbE alloy layer includes the one or more metal dopant element flake layers at least at a bottom edge of the BiSbE alloy layer.

21. The MRAM device of claim 18, wherein the PMA ferromagnetic layer is an annealed PMA ferromagnetic layer.

22. The MRAM device of claim 18, wherein after annealing the PMA ferromagnetic layer, the BiSbE alloy layer has or less roughness (R a ).

23. The MRAM device of claim 18, wherein the BiSbE alloy layer has a rocking curve of 11 degrees or less.

24. The MRAM device of claim 18, wherein after annealing the PMA ferromagnetic layer, the BiSbE alloy layer is a topological insulator.

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