Spin orbit torque magnetic device and method of manufacturing the same

Abstract

The present invention relates to spin-orbit torque magnetic devices and methods of manufacturing the same. According to an embodiment, a magnetic device can include a magnetic bias layer, a spin Hall layer on the magnetic bias layer, a free magnetic layer on the spin Hall layer, an intermediate layer on the free magnetic layer, and a reference magnetic layer on the intermediate layer, wherein the spin Hall layer includes a first spin Hall layer and a second spin Hall layer formed of materials having opposite signs of spin Hall angle, respectively. The magnetic device can be a magnetic random access memory or a spin logic device.

Description

TECHNICAL FIELD

[0001] The present application relates generally to the field of spintronics, and more particularly, to a spin-orbit torque magnetic device with high switching efficiency and a method of manufacturing the same, which can include magnetic random access memory and spin logic devices. BACKGROUND

[0002] A spin-orbit torque (SOT) magnetic spin valve or magnetic tunnel junction is a new type of high speed, low energy consumption, long life non-volatile magnetic device, which is considered as a candidate for the next generation of magnetic devices, and is expected to be applied to spintronic devices such as magnetic random access memory and spin logic devices. At present, for a thin film with perpendicular magnetic anisotropy, the spin current caused by the spin Hall effect cannot directly flip the perpendicular magnetic moment, and usually needs the assistance of a magnetic field or an equivalent magnetic field parallel to the current to achieve SOT magnetic moment switching. Under the condition of zero external magnetic field, this auxiliary equivalent magnetic field can be provided by exchange bias effect or interlayer magnetic coupling effect. For example, the prior application patent CN105280214B entitled "Current-driven magnetic random access memory and spin logic device" of the present applicant discloses a magnetic random access memory and spin logic device using an equivalent magnetic field to assist in flipping a free magnetic layer, the whole text of which is incorporated herein by reference. SUMMARY

[0003] An embodiment of the present application provides a magnetic device, comprising: a magnetic bias layer; a spin Hall layer on the magnetic bias layer; a free magnetic layer on the spin Hall layer; an intermediate layer on the free magnetic layer; and a reference magnetic layer on the intermediate layer, wherein the spin Hall layer comprises a first spin Hall layer and a second spin Hall layer, and the first and second spin Hall layers are respectively formed by materials with opposite signs of spin Hall angle.

[0004] In some embodiments, the magnetic bias layer has in-plane magnetic anisotropy, and the free magnetic layer and the reference magnetic layer have perpendicular magnetic anisotropy.

[0005] In some embodiments, the magnetic bias layer has perpendicular magnetic anisotropy, and the free magnetic layer and the reference magnetic layer have in-plane magnetic anisotropy.

[0006] In some embodiments, the spin Hall layer has a thickness to induce ferromagnetic coupling or antiferromagnetic coupling between the bias magnetic layer and the free magnetic layer.

[0007] In some embodiments, the second spin Hall layer contacts the free magnetic layer, and the first spin Hall layer has a greater thickness than the second spin Hall layer.

[0008] In some embodiments, the first and second spin Hall layers each have a thickness in a range of 0.2 nm to 3 nm.

[0009] In some embodiments, the magnetic device is a magnetic memory or a spin logic device.

[0010] Another embodiment of the present invention provides a method of fabricating a magnetic device, comprising: a. forming a pattern of a spin Hall layer on a substrate; b. forming a photoresist pattern on the substrate and the pattern of the spin Hall layer, the photoresist pattern having an opening to expose a portion of the spin Hall layer; c. depositing a multilayer film structure on the exposed portion of the spin Hall layer and the photoresist pattern, the multilayer film structure comprising a free magnetic layer, an intermediate layer, and a reference magnetic layer deposited in sequence; d. removing the photoresist pattern, thereby removing a portion of the multilayer film structure located on the photoresist pattern, leaving a portion of the multilayer film structure located on the spin Hall layer; e. depositing an insulating material layer on the substrate with the spin Hall layer and the multilayer film structure, and etching the insulating material layer to expose at least the multilayer film structure; and f. forming a top electrode in contact with the multilayer film structure.

[0011] In some embodiments, the substrate has a first bottom electrode and a second bottom electrode formed thereon, and the pattern of the spin Hall layer formed in step a connects the first and second bottom electrodes, the portion of the spin Hall layer exposed through the opening of the photoresist pattern in step b is located between the first and second bottom electrodes.

[0012] In some embodiments, etching the insulating material layer in step e also includes portions of the spin Hall layer located on both sides of the multilayer film structure, and forming the first and second bottom electrodes in step f also includes forming the first and second bottom electrodes on both sides of the top electrode and in contact with the spin Hall layer, respectively.

[0013] In some embodiments, the pattern of the spin Hall layer formed in step a includes a first spin Hall layer and a second spin Hall layer.

[0014] In some embodiments, the pattern of the spin Hall layer formed in step a includes only a first spin Hall layer, and the multilayer film structure deposited in step c also includes a second spin Hall layer in contact with the first spin Hall layer.

[0015] In some embodiments, a pattern of a biasing magnetic layer between the substrate and the spin Hall layer is also formed simultaneously when forming the pattern of the spin Hall layer in step a.

[0016] In some embodiments, a bias magnetic layer pattern is formed in the substrate prior to forming the pattern of the spin Hall layer, the pattern of the bias magnetic layer corresponding to the central region of the pattern of the spin Hall layer.

[0017] The above and other features and advantages of the present invention will become apparent from the following description of exemplary embodiments taken in conjunction with the accompanying drawings. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a self-rotating torque magnetic device in the prior art.

[0019] Figure 2 This is a schematic diagram demonstrating the principle of magnetic moment reversal using the spin Hall effect.

[0020] Figure 3 This is a schematic diagram of a self-rotating torque magnetic device according to an embodiment of the present invention.

[0021] Figures 4 to 10 This is a schematic diagram of the steps of a method for manufacturing a self-rotating torque magnetic device according to an embodiment of the present invention.

[0022] Figure 11 This is a schematic diagram of the structure of a self-rotating torque magnetic device according to another embodiment of the present invention. Detailed Implementation

[0023] Hereinafter, exemplary embodiments according to this application will be described in detail with reference to the accompanying drawings. Note that the drawings may not be drawn to scale. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments of this application, and this application is not limited to the exemplary embodiments described herein.

[0024] Figure 1 A prior art spin-transfer torque magnetic device 10 is shown. For example... Figure 1 As shown, the spin-transfer torque magnetic device 10 includes a bias magnetic layer 11, a spin Hall layer 12, a free magnetic layer 13, a spacer layer 14, and a reference magnetic layer 15 sequentially formed on a substrate (not shown). A top electrode 16 may also be formed on the reference magnetic layer 15, and a first bottom electrode 17 and a second bottom electrode 18 may be formed on opposite sides of the spin Hall layer 12. The first bottom electrode 17 and the second bottom electrode 18 can be used to apply an in-plane current flowing through the spin Hall layer 12, and one of the first bottom electrode 17 and the second bottom electrode 18 can be used together with the top electrode 16 to apply a vertical current flowing through the magnetic device 10. Although Figure 1 Only two bottom electrodes are shown, but it should be understood that, as needed, such as when used as a spin logic device, as discussed in the applicant's prior invention patent CN105280214B, additional electrodes may be added to the spin Hall layer 12. Figure 2The opposite sides or the other opposite sides (i.e. perpendicular to the paper) form more bottom electrodes, for example a third bottom electrode and a fourth bottom electrode. In Figure 1 particular, the reference magnetic layer 15 is shown to have a fixed perpendicular magnetization, the free magnetic layer 13 has a reversible perpendicular magnetization, and the bias magnetic layer 11 has an in-plane magnetization to provide an auxiliary bias magnetic field to the free magnetic layer 13. However, it should be understood that the reference magnetic layer 15 and the free magnetic layer 13 can also have in-plane magnetization, in which case the bias magnetic field 11 can have a perpendicular magnetization.

[0025] Figure 2 is a schematic diagram illustrating the principle of using the spin Hall effect to perform a magnetic moment flip of the free magnetic layer. Referring to Figure 1 and Figure 2 , when an in-plane charge current I W is applied to the spin Hall layer 12, due to strong spin-orbit coupling, a spin current is generated on each surface of the spin Hall layer 12, as shown by the arrows with circles in Figure 2 . The magnitude and direction of the spin current are determined by the spin Hall angle of the material forming the spin Hall layer 12. The magnitude of the spin Hall angle defines the ratio of the spin current to the charge current, which reflects the conversion efficiency between the charge current and the spin current. The stronger the spin-orbit coupling, the larger the spin Hall angle. The sign of the spin Hall angle defines the spin polarization direction of the spin current. When the direction of the charge current I W is fixed, the spin polarization direction of the spin current generated by materials with opposite signs of the spin Hall angle are opposite to each other. For example, when a positive spin Hall angle generates a counterclockwise spin polarization direction as shown in Figure 2 , a negative spin Hall angle generates an opposite clockwise spin polarization direction. When the spin Hall layer 12 is in direct contact with the free magnetic layer 13, the spin current in the spin Hall layer 12 diffuses to the free magnetic layer 13, and exerts a spin-orbit torque (SOT) on the free magnetic layer 13, which, together with the bias magnetic field applied by the bias magnetic layer 11, causes the magnetic moment of the free magnetic layer 13 to flip.

[0026] To achieve the magnetic moment flip of the free magnetic layer 13, it is required that the bias magnetic layer 11 applies a sufficient bias magnetic field, and at the same time, there is a sufficient current density in the spin Hall layer 12 to apply a sufficient spin-orbit torque to the free magnetic layer 13. To increase the current density in the spin Hall layer 12, the spin Hall layer 12 is usually made very thin, for example in the range of 1-4 nm. However, this causes many problems, for example, it increases the manufacturing difficulty, and the flip energy consumption is high, etc. In the following, some exemplary embodiments of the present application will be discussed in detail with reference to the accompanying drawings, which can solve or alleviate the above and other problems in the prior art, but the present application is not limited thereto.

[0027] Figure 3 is a schematic diagram of a structure of a spin transfer torque magnetic device according to an embodiment of the present application. As shown inFigure 3 As shown, the spin-transfer torque magnetic device 20 includes a biasing magnetic layer 21, a first spin-Hall layer 22A, a second spin-Hall layer 22B, a free magnetic layer 23, a spacer layer 24, and a reference magnetic layer 25, which are formed in sequence on an insulating substrate (not shown). A top electrode 26 can also be formed on the reference magnetic layer 25, and a first bottom electrode 27 and a second bottom electrode 28 can be formed on opposite sides of the first and second spin-Hall layers 22A and 22B. The first and second bottom electrodes 27 and 28 can be used to apply in-plane currents through the first and second spin-Hall layers 22A and 22B, and one of the first and second bottom electrodes 27 and 28 can be used together with the top electrode 26 to apply a perpendicular current through the magnetic device 20. Although Figure 3 Only two bottom electrodes are shown, but it should be understood that more bottom electrodes, such as a third bottom electrode and a fourth bottom electrode, can be formed on the opposite sides or on the other (i.e., out-of-plane) opposite sides of the spin-Hall layers 22, as discussed in the applicant’s prior invention patent CN105280214B, for example, when used as a spin-logic device. Figure 3 More bottom electrodes, such as a third bottom electrode and a fourth bottom electrode, can be formed on the opposite sides or on the other (i.e., out-of-plane) opposite sides of the spin-Hall layers 22, as discussed in the applicant’s prior invention patent CN105280214B, for example, when used as a spin-logic device. Figure 3 In the embodiment shown, the reference magnetic layer 25 is shown to have a fixed perpendicular magnetization, the free magnetic layer 23 has a reversible perpendicular magnetization, and the biasing magnetic layer 21 has an in-plane magnetization to provide an auxiliary bias magnetic field to the free magnetic layer 23. However, it should be understood that the reference magnetic layer 25 and the free magnetic layer 23 can also have in-plane magnetization, in which case the biasing magnetic layer 21 can have a perpendicular magnetization.

[0028] The biasing magnetic layer 21 can be formed of a ferromagnetic material, including but not limited to Co, Fe, Ni, and alloys including one or more of them. The magnetization of the biasing magnetic layer 21 remains unchanged during the operation of the magnetic device 20, so the biasing magnetic layer 21 can be formed using a material with a large coercivity, or can be formed to have a large thickness. In some embodiments of the present invention, the thickness of the biasing magnetic layer 21 can be in the range of 1 nm to 30 nm, preferably in the range of 2 nm to 20 nm. In other embodiments, an anti-ferromagnetic pinning layer can also be provided between the biasing magnetic layer 21 and the substrate to pin the magnetization direction of the biasing magnetic layer 21, or the biasing magnetic layer 21 can adopt a synthetic anti-ferromagnetic (SAF) structure. When the biasing magnetic layer 21 has a perpendicular magnetization, one or more buffer layers can also be formed between the biasing magnetic layer 21 and the substrate.

[0029] The first spin-Hall layer 22A and the second spin-Hall layer 22B are both formed of a conductor material with strong spin-orbit coupling properties, which can also be collectively referred to as the spin-Hall layer 22. As previously discussed with reference to the applicant’s prior invention patent CN105280214B, the spin-Hall layer 22 can be formed of a material with strong spin-orbit coupling properties, such as Pt, W, Ta, and alloys including one or more of them. Figure 1 and 2As described above, when a current flows through a conductor material having a strong spin-orbit coupling property, a spin current can be formed on the surface of the conductor material due to the spin Hall effect. Examples of such a conductor material include, but are not limited to, metals or alloys such as Pt, Au, Ta, Pd, Ir, W, Bi, Pb, Hf, IrMn, PtMn, AuMn, topological insulators such as Bi2Se3and Bi2Te3, and rare earth materials such as Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Te, Dy, Ho, Er, Tm, Yi, Lu, etc., among which Y, Nd, Sm, Eu, Gd, Te, Dy, Ho, Er, and Tm are preferable because they have a strong spin-orbit coupling and thus have a large spin Hall angle. As described above, in order to achieve a large current density, the thickness of the spin Hall layer 22 can be small, for example, in the range of 0.4 nm to 10 nm, preferably in the range of 0.4 nm to 6 nm, and more preferably in the range of 0.5 nm to 4 nm. Further, preferably, the thickness of each of the first spin Hall layer 22A and the second spin Hall layer 22B can be in the range of 0.2 nm to 5 nm, preferably in the range of 0.2 nm to 3 nm, and the thickness of the second spin Hall layer 22B can be smaller than the thickness of the first spin Hall layer 22A. In some embodiments, the thicknesses of the first spin Hall layer 22A and the second spin Hall layer 22B can be selected so that it induces an anti-ferromagnetic coupling or a ferromagnetic coupling between the bias magnetic layer 21 and the free magnetic layer 23.

[0030] It should be noted that, in the present application, the material forming the first spin Hall layer 22A and the material forming the second spin Hall layer 22B have opposite spin Hall angles, i.e., the signs of the spin Hall angles are opposite to each other. That is, when the same current is applied in the first spin Hall layer 22A and the second spin Hall layer 22B, the spin polarization direction of the spin current accumulated on the surface of the first spin Hall layer 22A is opposite to the spin polarization direction of the spin current accumulated on the surface of the second spin Hall layer 22B. For example, one of the first spin Hall layer 22A and the second spin Hall layer 22B can be formed of Pt or Ir, and the other can be formed of Ta or W. Of course, they can also be formed of other materials having a spin Hall effect listed above or developed in the future, as long as the signs of the spin Hall angles of the two are opposite to each other.

[0031] Although Figure 3It is shown that the first spin Hall layer 22A and the second spin Hall layer 22B have the same shape, but the present application is not limited thereto. For example, in some embodiments, the second spin Hall layer 22B can be deposited and etched together with the spin valve or tunnel junction structure thereon, so as to have the same shape as the spin valve or tunnel junction, while the first spin Hall layer 22A can be deposited and etched separately, extending from two or four sides of the spin valve or tunnel junction to be electrically connected to the bottom electrode. In addition, the biasing magnetic layer 21 can have the same shape as the first spin Hall layer 22A, for example, the biasing magnetic layer 21 can be deposited and etched together with the first spin Hall layer 22A.

[0032] Located above the second spin Hall layer 22B is a spin valve or tunnel junction structure composed of a free magnetic layer 23, an intermediate layer 24 and a reference magnetic layer 25, wherein the free magnetic layer 23 is in direct contact with the second spin Hall layer 22B. The free magnetic layer 23 and the reference magnetic layer 25 can both be formed of ferromagnetic materials, wherein the free magnetic layer 23 has a reversible magnetic moment, and the reference magnetic layer 25 has a fixed magnetic moment. For a spin valve, the intermediate layer 24 is formed of a non-magnetic conductive material; for a tunnel junction, the intermediate layer 24 is formed of a non-magnetic insulator such as a metal oxide. Since the structure of the spin valve and the tunnel junction is known in the art, it will not be described in detail here. It should be understood that the existing or future developed spin valve and tunnel junction structure can be applied to the embodiments of the present application as long as the free layer is in contact with the spin Hall layer, and the present application is not limited to any particular spin valve and tunnel junction structure.

[0033] Some examples of structures that can be used in the present application are described below, wherein the numbers in the brackets behind the materials are the thickness of the material layer, in nanometers.

[0034] Example 1: Ta(5) / Co(2) / Ir(1) / W(0.6) / CoFeB(0.9) / MgO(2) / CoFeB(1.1) / W(0.4) / [Co0.4) / Pt(0.8)]3 / Pt(3)

[0035] wherein 5 nm of Ta is a buffer layer, also called a seed layer, 2 nm of Co is a biasing magnetic layer with in-plane magnetic anisotropy, 1 nm of Ir is a first spin Hall layer, 0.6 nm of W is a second spin Hall layer, both with opposite sign of the spin Hall angle, 0.9 nm of CoFeB is a free magnetic layer with perpendicular magnetic anisotropy, 2 nm of MgO is an intermediate layer, i.e. a non-magnetic insulating tunneling layer, 1.1 nm of CoFeB is a reference magnetic layer, 0.4 nm of W layer is used to induce an anti-ferromagnetic coupling, [Co0.4) / Pt(0.8)]3 multilayer structure is used as a pinning layer, comprising 0.4 nm of Co layer and 0.8 nm of Pt layer and repeated three times, with perpendicular magnetic anisotropy, and the magnetic moment of the CoFeB reference magnetic layer is pinned by the anti-ferromagnetic coupling induced by the W layer, 3 nm of Pt layer can be used as a protective cap layer.

[0036] Example 2: Ta(5) / Co(2) / Ir(1) / Ta(0.8) / CoFeB(0.9) / MgO(2) / CoFeB(1.1) / W(0.4) / [Co0.4) / Pt(0.8)]3 / Ru(0.85) / [Co0.4) / Pt(0.8)]5 / Pt(3)

[0037] Example 2 is basically similar to Example 1, except for the following points: the second spin Hall layer is a 0.8 nm Ta layer; the pinning layer has a synthetic anti-ferromagnetic (SAF) structure, with a 0.85 nm Ru layer in the middle to induce an anti-ferromagnetic coupling, so that the two ferromagnetic multilayer films on the sides are anti-ferromagnetically coupled to each other.

[0038] The following is a comparison between the magnetic device 10 shown in Figure 1 and the magnetic device 10 shown in Figure 3The magnetic device 20 is shown to illustrate the features and principles of embodiments of the present application. In the magnetic device 10, the single spin Hall layer 12 is located between the free magnetic layer 13 and the bias magnetic layer 11, and in order to flip the free magnetic layer 13, the magnetic anisotropy energy k1 of the free magnetic layer 13 must be overcome, where the magnetic anisotropy energy k2 of the bias magnetic layer 11 is greater than the magnetic anisotropy energy k1 of the free magnetic layer 13, so that the free magnetic layer 13 is flipped while the bias magnetic layer 11 is not flipped. The present inventors have found that because the spin polarization directions of the accumulated spin current on the upper surface and the lower surface of the spin Hall layer 12 are opposite to each other, the torque exerted by the spin Hall layer 12 on the upper free magnetic layer 13 and the torque exerted on the lower bias magnetic layer 11 are in opposite directions. For example, when the spin current in the spin Hall layer 12 exerts a torque of ΔT on the free magnetic layer 13, the torque exerted on the bias magnetic layer 11 is -ΔT. Further, when the bias magnetic layer 11 exerts an auxiliary bias magnetic field on the free magnetic layer 13 through exchange bias or interlayer coupling, the opposite torque -ΔT exerted by the spin Hall layer 12 on the bias magnetic layer 11 has a negative effect on the flipping of the free magnetic layer 13, which is not conducive to the flipping of the magnetic moment of the free magnetic layer 13. Therefore, a greater current density needs to be provided on the spin Hall layer 12 to successfully realize the flipping of the magnetic moment of the free magnetic layer 13, which also requires the bias magnetic layer 11 to have a large magnetic anisotropy energy k2.

[0039] Unlike the magnetic device 10, in the magnetic device 20 of an embodiment of the present application, the first spin Hall layer 22A and the second spin Hall layer 22B are formed of materials with opposite signs of the spin Hall angle. That is, the torque exerted by the second spin Hall layer 22B on the free magnetic layer 23 and the torque exerted by the first spin Hall layer 22A on the bias magnetic layer 21 are in the same direction. Therefore, when the bias magnetic layer 21 exerts an auxiliary bias magnetic field on the free magnetic layer 23 through exchange bias or interlayer coupling, the torque exerted by the first spin Hall layer 22A on the bias magnetic layer 21 has a positive effect on the flipping of the free magnetic layer 23, further promoting the flipping of the magnetic moment of the free magnetic layer 23. Therefore, compared with the magnetic device 10, the magnetic device 20 of the present application can reduce the current density applied to the spin Hall layer 22 (including 22A and 22B), while also reducing the magnetic anisotropy requirement of the bias magnetic layer 21.

[0040] As a fabrication process of the above magnetic devices, generally includes deposition of each film layer and corresponding photolithography etching process, generally can adopt electron beam etching, reactive ion etching, chemical reaction etching, chemical discrimination etching, etc. One difficulty of etching process is to etch accurately to the desired depth, which generally can be achieved by using etching stop layer, controlling etching time and rate, or selecting specific chemical reaction etching solution. As mentioned above, in the magnetic devices 10 and 20, in order to improve current density, the spin Hall layer generally has very thin thickness, for example in the range of 1-6 nm. The wafer adopted by semiconductor process can reach the size of 12 inches, on such a large wafer, it is difficult to control the etching process to stop accurately at, for example, the spin Hall layer. For example, in some parts of the wafer, when etching the spin valve or tunnel junction, the spin Hall layer below it can also be etched off due to over-etching, which can cause the circuit connection between the electrode and the spin valve or magnetic tunnel junction to be disconnected, so that the storage cell or logic device is disabled. Therefore, how to manufacture the above magnetic devices with high yield is still a difficult problem. The following will discuss embodiments of the method for manufacturing magnetic devices, which can solve one or more of the above problems, but the present application is not limited thereto.

[0041] Figures 4 to 10 is a schematic diagram of the method steps for manufacturing a spin transfer torque magnetic device according to an embodiment of the present application, where the left side is a cross-sectional view and the right side is a top view. Referring to Figure 4 , first, the first bottom electrode 31 and the second bottom electrode 32 can be formed on the substrate 30. For example, a mask pattern of photoresist can be formed on the substrate 30, a portion of the substrate 30 is etched, and then an electrode metal layer is deposited in the etched portion, the electrode metal layer on the mask pattern is removed by lift-off process, leaving the first bottom electrode 31 and the second bottom electrode 32, resulting in the structure shown in Figure 4 . In another embodiment, instead, an electrode metal layer can be deposited on the substrate 30, a mask pattern of photoresist is formed on the electrode metal layer, a portion of the electrode metal layer is etched to generate the first bottom electrode 31 and the second bottom electrode 32, and then an insulating material such as SiO2 or the like is deposited on the substrate 30 and the mask pattern to fill the surrounding area of the first bottom electrode 31 and the second bottom electrode 32, and finally the mask pattern is removed to obtain the structure shown in Figure 4 . Of course, the first bottom electrode 31 and the second bottom electrode 32 can also be formed by other methods. Although not shown, the first bottom electrode 31 and the second bottom electrode 32 can be extended to connect to other circuit structures, for example. In some embodiments, as will be discussed in further detail below, the step of forming the first bottom electrode 31 and the second bottom electrode 32 can be omitted.

[0042] Referring to Figure 5A spin Hall layer 33 is deposited on the substrate 30 with the first bottom electrode 31 and the second bottom electrode 32. In some embodiments, the spin Hall layer 33 can include two spin Hall layers with spin Hall angles of opposite signs. Although not shown, in some embodiments, a biasing magnetic layer can be deposited on the substrate 30 with and below the spin Hall layer 33. In some embodiments, instead, the biasing magnetic layer can be deposited and etched separately before depositing the spin Hall layer 33, for example it can be formed on the substrate 30 between the first bottom electrode 31 and the second bottom electrode 32, before depositing the spin Hall layer 33. Referring back to Figure 5 A mask pattern 34 of photoresist can be formed on the spin Hall layer 33.

[0043] Referring back to Figure 6 The spin Hall layer 33 covering the substrate 30 is etched using the mask pattern 34 of photoresist to obtain a spin Hall layer 33 of desired shape. In Figure 6 The spin Hall layer 33 extends from the first bottom electrode 31 to the second bottom electrode 32 so that an in-plane current can be applied to the spin Hall layer 33 using the first bottom electrode 31 and the second bottom electrode 32.

[0044] Referring back to Figure 7 A mask pattern 35 of photoresist is formed on the substrate 30 with the spin Hall layer 33, exposing only a portion of the spin Hall layer 33 between the first bottom electrode 31 and the second bottom electrode 32, for example it can have an elliptical or rectangular shape. Then, a spin valve or tunnel junction structure layer 36 can be deposited on the exposed portion of the spin Hall layer 33 and the mask pattern 35. Preferably, the spin valve or tunnel junction structure layer 36 is deposited by a directional deposition process and the mask pattern 35 has a greater thickness than the structure layer 36 so that the structure layer 36 on the mask pattern 35 is not connected to the structure layer 36 on the spin Hall layer 33.

[0045] Thus, referring back to Figure 8 The spin valve or tunnel junction structure layer 36 on the mask pattern 35 can be removed at the same time as the mask pattern 35 is removed, in a so-called lift-off process, leaving the spin valve or tunnel junction structure layer 36 on the spin Hall layer 33. Since the structure layer 36 is deposited by a directional deposition process so that portions of the sidewalls of the mask pattern 35 are not covered by the structure layer 26 but are exposed to the outside, the lift-off process can be easily performed, for example using a suitable chemical solution such as acetone to dissolve the mask pattern 35, thereby removing the mask pattern 35 and the structure layer 36 on it.

[0046] In some embodiments, the spin valve or tunnel junction structure layer 36 can include a free layer in direct contact with the spin Hall layer 33, an intermediate layer on the free layer, and a reference magnetic layer on the intermediate layer, as previously described with reference to Figure 1 and Figure 3 In some embodiments, when the spin Hall layer 33 deposited in Figure 6 includes only a single first spin Hall layer, the spin valve or tunnel junction structure layer 36 can also include a second spin Hall layer below the free layer to contact the first spin Hall layer. That is, the first and second spin Hall layers can be deposited and etched separately to have different shapes. Of course, as previously described, the first and second spin Hall layers can also be deposited consecutively and etched in the same step to have the same shape.

[0047] With continuing reference to Figure 9 , a layer of non-magnetic insulating material 37 is deposited on the resulting structure, and a portion of the insulating material layer 37 is etched away using a mask pattern (not shown) to expose the spin valve or tunnel junction structure layer 36. Although Figure 9 the insulating layer 37 is shown as being higher than the structure layer 36, the two can also have substantially the same height.

[0048] Finally, with reference to Figure 10 , a top electrode metal layer 38 is deposited on the insulating layer 37, and a portion of the metal layer 38 is etched away using a mask pattern (not shown) to leave a pattern of top electrodes 38.

[0049] In the above fabrication method, the spin valve or tunnel junction structure layer 36 and the spin Hall layer 33 (which can include a single layer or double layers) are deposited and patterned separately, the spin Hall layer 33 can be patterned using conventional mask patterns and etching processes, while the spin valve or tunnel junction structure layer 36 is patterned using a lift-off process so that the patterning of the structure layer 36 does not affect, for example, etching away of the spin Hall layer 33 thereunder, reducing process difficulty and improving product yield.

[0050] As previously described, the first and second bottom electrodes 31 and 32 can also not be formed in the substrate 30, Figure 11 such embodiments are shown. With reference to Figure 11 , a biasing magnetic layer 40 can be formed in the substrate 30 prior to deposition of the spin Hall layer 33. The other fabrication method can then be as described above with reference to Figures 4-8The description is substantially the same. After deposition of the non-magnetic insulating layer 37, portions of the insulating layer 37 can be removed by a mask etching process, exposing portions of the spin valve or tunnel junction structure layer 36 and the spin hall layer 33 for forming bottom electrodes. Since the insulating layer 37 can use an oxide such as Si02, while the spin valve or tunnel junction structure layer 36 and the spin hall layer 33 are both metals, an anisotropic dry or wet etch can be utilized such that portions of the oxide insulating layer 37 are etched away while the etch stops when reaching the metal layers. Then, a conformal deposition process can be employed to deposit electrode layers that contact the spin hall layer 33 and the spin valve or tunnel junction structure layer 36. Finally, the electrode metal layers are etched using a mask pattern to obtain the top electrode 38, the first bottom electrode 41 and the second bottom electrode 42, as shown in Figure 11

[0051] The above describes the basic principles of the present application in conjunction with specific embodiments, however, it should be noted that the advantages, benefits, effects and the like mentioned in the present application are only examples and are not limiting, and these advantages, benefits, effects and the like cannot be considered as necessary for each embodiment of the present application. In addition, the above specific details disclosed are only for the purpose of example and understanding, and are not limiting, and the above details do not limit the present application to be necessarily implemented with the above specific details.

[0052] The block diagrams of the devices, apparatuses, equipment, systems involved in the present application are only illustrative examples and are not intended to require or imply that the connections, arrangements, configurations shown in the block diagrams must be connected, arranged, configured. As those skilled in the art will recognize, these devices, apparatuses, equipment, systems can be connected, arranged, configured in any manner. Words such as "include", "contain", "have" and the like are open-ended words, mean "including but not limited to", and can be used interchangeably. The words "or" and "and" used herein mean the word "and / or", and can be used interchangeably unless the context clearly indicates otherwise. The word "such as" used herein means the phrase "such as but not limited to", and can be used interchangeably.

[0053] It should also be noted that in the devices, equipment and methods of the present application, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be considered as equivalent solutions of the present application.

[0054] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other aspects without departing from the scope of the application. Thus, the present application is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. ​

[0055] The foregoing description has been presented for the purposes of illustration and description. Furthermore, the description is not intended to limit the embodiments of the application to the forms disclosed herein. Although the above discussion has focused on various example aspects and embodiments, those skilled in the art will recognize certain modifications, permutations, additions, and sub-combinations thereof.

Claims

1. A magnetic device, comprising: a magnetic bias layer; a spin Hall layer on the magnetic bias layer; a free magnetic layer on the spin Hall layer; an intermediate layer on the free magnetic layer; and a reference magnetic layer on the intermediate layer, wherein the spin Hall layer comprises a first spin Hall layer and a second spin Hall layer, the first and second spin Hall layers are formed of materials with opposite signs of spin Hall angle, the first spin Hall layer is in contact with the magnetic bias layer, and the second spin Hall layer is in contact with the free magnetic layer, the spin Hall layer has a thickness to induce ferromagnetic or anti-ferromagnetic coupling between the magnetic bias layer and the free magnetic layer. the magnetic bias layer has in-plane magnetic anisotropy, and the free magnetic layer and the reference magnetic layer have perpendicular magnetic anisotropy, or 2. The magnetic device of claim 1, wherein, the magnetic bias layer has perpendicular magnetic anisotropy, and the free magnetic layer and the reference magnetic layer have in-plane magnetic anisotropy. the thickness of each of the first and second spin Hall layers is in a range of 0.2 nm to 3 nm.

3. The magnetic device of claim 1, wherein, the magnetic device is a magnetic memory or a spin logic device.

4. The magnetic device of claim 1, wherein, 5. A method of fabricating the magnetic device of any one of claims 1 to 4, comprising: a. forming a pattern of a spin Hall layer on a substrate; b. forming a photoresist pattern on the substrate and the pattern of the spin Hall layer, the photoresist pattern having openings to expose a portion of the spin Hall layer; c. depositing a multi-layer film structure on the exposed portion of the spin Hall layer and the photoresist pattern, the multi-layer film structure comprising a free magnetic layer, an intermediate layer, and a reference magnetic layer deposited in sequence; d. removing the photoresist pattern, thereby removing a portion of the multi-layer film structure on the photoresist pattern, leaving a portion of the multi-layer film structure on the spin Hall layer; e. depositing an insulating material layer on the substrate with the spin Hall layer and the multi-layer film structure, and etching the insulating material layer to expose at least the multi-layer film structure; and f. forming a top electrode in contact with the multi-layer film structure, wherein the pattern of the spin Hall layer is formed in step a, and simultaneously a pattern of a magnetic bias layer between the substrate and the spin Hall layer is formed, or the pattern of the magnetic bias layer is formed in the substrate before the pattern of the spin Hall layer is formed, the pattern of the magnetic bias layer corresponding to a middle region of the pattern of the spin Hall layer, the spin Hall layer having a thickness to induce ferromagnetic or anti-ferromagnetic coupling between the magnetic bias layer and the free magnetic layer. the substrate has a first bottom electrode and a second bottom electrode formed thereon, and the pattern of the spin Hall layer formed in step a connects the first and second bottom electrodes, and the portion of the spin Hall layer exposed through the openings of the photoresist pattern in step b is between the first bottom electrode and the second bottom electrode, or 6. The method of claim 5, wherein, ​ Etching the insulating material layer in step e also includes portions of the spin Hall layer located on both sides of the multilayer film structure, and in step f, a first bottom electrode and a second bottom electrode are also formed, respectively on both sides of the top electrode and in contact with the spin Hall layer.

7. The method of claim 5, wherein, The pattern of the spin Hall layer formed in step a includes a first spin Hall layer and a second spin Hall layer, or The pattern of the spin Hall layer formed in step a includes only a first spin Hall layer, and the multilayer film structure deposited in step c also includes a second spin Hall layer in contact with the first spin Hall layer.

8. The method of claim 7, wherein, The thickness of each of the first spin Hall layer and the second spin Hall layer is in the range of 0.2 nm to 3 nm. The thickness of each of the first spin Hall layer and the second spin Hall layer is in the range of 0.2 nm to 3 nm.

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