Application of high orbital flow / strong spin-orbital coupling thin film heterojunction and spin electronic device
By introducing a strong spin-orbit coupling layer onto the high-orbit flow metal film layer, a high-orbit flow/strong spin-orbit coupling film heterojunction is formed, which solves the problem that traditional electronic devices are difficult to achieve low power consumption, significantly improves spin-orbit torque efficiency, reduces device power consumption, and achieves efficient magnetic moment flip.
Patent Information
- Application Number
- CN202510003376.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-02
- Publication Date
- 2025-04-25
AI Technical Summary
Due to the Joule heat generated by the charge flow, traditional electronic devices are difficult to achieve miniaturization and low power consumption. Spinel electronics has low power consumption but the current density of flipped magnetic moment is still relatively high, and a new material system is needed to improve spin-orbit torque efficiency.
High orbital flow/strong spin-orbit coupling film heterojunction is adopted. By introducing a strong spin-orbit coupling layer on the high orbital flow metal film layer, a "high orbital flow layer/strong SOC layer" film heterojunction is formed, which effectively absorbs the orbital flow and converts it into a strong spin flow, achieving high-efficiency flip of the magnetic moment of the adjacent magnetic layer thin film.
The spin-orbit torque efficiency is significantly improved at room temperature, with a maximum increase of 100 times, reducing the power consumption of the device, and the current density of the flipped magnetic moment is reduced to the order of 10-5A/cm2, suitable for the development of low-power spin electronic devices.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of low-power spin electronic materials, devices and chips, and specifically relates to a high orbital flow / strong spin-orbit coupling thin film heterojunction and a spin electronic logic device application. Background Art
[0002] With the rapid development of information technology today, traditional electronic devices have Joule heat generated by charge flow, and the miniaturization and low power consumption of electronic devices are facing severe bottlenecks. Electron spin is another property of electrons besides charge, which can be used to transmit and process information, that is, spintronics was born. Spintronics has extremely low power consumption in transmitting information, and can even complete the processing and storage of quantum information. It is an ideal medium for building quantum information chips. Typical applications include magnetic random access memory (MRAM). Currently, MRAM implemented by spin-orbit torque (SOT) has become a research hotspot. However, the current density of SOT-MRAM flipping magnetic moment is still high, and it is urgent to invent new material systems. The spin Hall effect is the effect of applying a transverse charge flow to generate a longitudinal spin flow under the action of spin-orbit coupling (SOC). Spin flow can be achieved without the movement of charge, realizing a dissipation-free process, so that the device does not generate Joule heat. The conversion efficiency between this charge flow and spin flow is expressed by the spin Hall angle (θ SH ) represents. The fundamental source of the spin Hall effect is the orbital Hall effect. The orbital Hall effect is that when a material is subjected to an electric field, a net orbital angular momentum flow (orbital flow) is generated inside the material in a direction perpendicular to the electric field, thereby generating a net angular momentum accumulation at both ends of the material. Because the net orbital angular momentum accumulation (or orbital angular momentum flow) generated by the orbital Hall effect can be converted into pure spin current through SOC, the maximum value of the orbital Hall conductivity of different metals calculated by first principles is about four times the spin Hall conductivity, but the orbital flow is not easy to be directly used for the spin-orbit torque flipping magnetic moment, and has not yet been developed and utilized. The present invention considers introducing a strong SOC layer on a metal film layer with a high orbital flow (referred to as a "high orbital flow layer") to form a "high orbital flow layer / strong SOC layer" thin film heterojunction, thereby effectively absorbing the orbital flow and converting it into a strong spin flow. This strong spin flow achieves a high-efficiency flipping of the magnetic moment of the adjacent magnetic layer film. The present invention uses a strong spin-orbit coupling heavy metal and a high orbital Hall effect metal to construct a thin film heterojunction, providing a new path for developing orbital flow (orbital angular momentum flow) electronic devices. Summary of the invention
[0003] The purpose of the present invention is to propose a high orbital flow / strong spin-orbit coupling thin film heterojunction and spintronic device application in view of the problems existing in the background technology. The high orbital flow / strong spin-orbit coupling thin film heterojunction of the present invention can realize the effective utilization of orbital flow and orbital angular momentum at room temperature, thereby realizing a huge improvement in the efficiency of spin-orbit torque, which is increased by up to 100 times; and the heterojunction film has low resistivity, good semiconductor compatibility, and low preparation cost, and is suitable for industrial large-scale production by magnetron sputtering. Spin logic devices based on the "high orbital flow layer / strong SOC layer / magnetic layer (or antiferromagnetic layer)" thin film heterojunction, the current density of the device's flip magnetic moment is reduced to 10 -5 A / cm 2 It provides an important technical solution for future low-power spin electronic devices.
[0004] To achieve the above purpose, the technical solution adopted by the present invention is as follows:
[0005] A high orbital flow / strong spin-orbit coupling thin film heterojunction is a "high orbital flow thin film / strong spin-orbit coupling thin film" heterostructure formed by a thin film with huge orbital flow and a thin film with strong spin-orbit coupling grown on a substrate; in the heterojunction thin film system, the bottom layer is a thin film layer with huge orbital flow, with a thickness of 10 to 120 nm, and the upper layer is a thin film layer with strong spin-orbit coupling, with a thickness of 0.5 to 2.0 nm; wherein the ratio of the thickness of the thin film layer with huge orbital flow to the thickness of the thin film layer with strong spin-orbit coupling is greater than 10:1.
[0006] Furthermore, the thin film layer material with high orbital flow has a large orbital Hall effect or orbital Rashba effect, specifically a single substance such as Ti, V, Cr, Mn, and their alloys or compound films.
[0007] Furthermore, the thin film layer material with strong spin-orbit coupling is W, Pt, Ta, Bi2Te3, etc.
[0008] Furthermore, the substrate is a silicon wafer or a sapphire substrate with a thermally oxidized surface; the thin film layer with high orbital flow and the thin film layer with strong spin-orbit coupling are grown on the substrate by physical vapor deposition or magnetron sputtering.
[0009] Preferably, the high orbital flow / strong spin-orbit coupling thin film heterojunction is prepared by magnetron sputtering of a high-purity metal target, and the specific process is: -5Pa, argon gas is introduced into the vacuum chamber at a flow rate of 20 Sccm. After the gas pressure stabilizes to 0.27-0.32 Pa, the magnetron sputtering power supply is turned on, and each target is pre-sputtered for 10 minutes at a DC power of 30 W. The purpose is to use argon ion bombardment to clean the target surface to remove the surface oxide layer and other impurities. After the pre-sputtering is completed, the target baffle is opened for coating. First, a thin film material with high orbital flow is grown at a power of 10 W, and then a thin film material with strong spin-orbit coupling is grown at a power of 5 W. After the set growth time is reached, the target baffle and the sputtering power supply are turned off to obtain a high orbital flow / strong spin-orbit coupling thin film heterojunction.
[0010] A spin electronic device comprises a substrate, a high orbital flow / strong spin-orbit coupling thin film heterojunction formed on the substrate, and a magnetic film layer or an antiferromagnetic film layer formed on the high orbital flow / strong spin-orbit coupling thin film heterojunction; wherein, in the high orbital flow / strong spin-orbit coupling thin film heterojunction, the thickness of the high orbital flow layer film is 10 to 120 nm, and the thickness of the strong spin-orbit coupling layer film is 0.5 to 2.0 nm.
[0011] Furthermore, the magnetic film layer is Co, CoFe, NiFe, CoFeB or Y3Fe5O 12 etc., the antiferromagnetic thin film layer is IrMn, Mn3Sn, NiO or CrO2 etc.
[0012] Furthermore, the thin film layer material with high orbital flow has a large orbital Hall effect or orbital Rashba effect, specifically a single substance such as Ti, V, Cr, Mn, and their alloys or compound films.
[0013] Furthermore, the thin film layer material with strong spin-orbit coupling is W, Pt, Ta, Bi2Te3, etc.
[0014] Furthermore, the thin film layer with high orbital flow and the thin film layer with strong spin-orbit coupling are grown on the substrate by physical vapor deposition or magnetron sputtering, and the thickness of different thin film layers in the heterojunction is adjusted by controlling the sputtering pressure, power and time of the metal target.
[0015] Furthermore, the strong spin-orbit coupling thin film target is a heavy metal target with a purity of not less than 99.99wt%, and the high orbital flow thin film target is a metal target with a purity of not less than 99.99wt%.
[0016] Furthermore, an RF current is passed through the high orbital flow / strong spin-orbit coupling film heterojunction. Due to the combined effects of the orbital Hall effect and the spin Hall effect, the orbital flow (the thicker the thickness, the greater the orbital flow) generated in the high orbital flow film is injected into the strong spin-orbit coupling film in the heterojunction and converted into a strong spin current. The spin current flows into the adjacent magnetic layer film, and the spin current generates a spin torque on the magnetic moment in the magnetic layer, causing the Larmor precession of the magnetic moment. Due to the anisotropic magnetoresistance effect of the magnetic layer, the total resistance of the device oscillates. The RF current and the oscillating resistance jointly generate a DC voltage signal in the sample, allowing us to quantitatively test the spin current absorbed by the ferromagnetic layer. Therefore, the spin torque-ferromagnetic resonance voltage (V ST-FMR ), the spin-orbit torque generation efficiency of the “high orbital flow film / strong spin-orbit coupling film” heterostructure can be fitted.
[0017] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:
[0018] The invention provides a high orbital flow / strong spin-orbit coupling thin film heterojunction and a spin electronic device application. The method is simple and easy to implement. The prepared high orbital flow / strong spin-orbit coupling thin film heterojunction has a significantly improved spin-orbit torque at room temperature compared with pure strong spin Hall effect heavy metal Pt, W, Ta and other thin films. Compared with pure strong spin Hall effect heavy metal material Pt, the spin flow generation efficiency of the high orbital flow / strong spin-orbit coupling thin film heterojunction is improved by more than 300%. By using the "high orbital flow thin film / strong spin-orbit coupling thin film" heterojunction, the reversal current density of the spin electronic device is reduced to 10 for the first time in a non-topological system. 5 A / cm 2 The power consumption of the device is greatly reduced. At the same time, the preparation cost of the thin film heterojunction is low, and uniform preparation can be achieved on large-area (8-inch and 12-inch) semiconductor wafers. The present invention forms a nano-thin film heterostructure by introducing high orbital flow materials and strong spin-orbit coupling materials, which provides a new technical method for making full use of orbital flow (orbital angular momentum) and improving spin-orbit torque. It has broad application prospects in many fields such as low-power spin electronics devices, such as current-driven magnetic moment reversal, spin-orbit torque magnetic tunnel junction memory, and spin logic devices. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 Ti(d Ti nm) / Pt(1nm) heterojunction spin-orbit torque generation efficiency variation law;
[0020] Figure 2This is the current density curve of magnetic moment reversal in the Ti(120nm) / Pt(1nm) / Co device of the embodiment. DETAILED DESCRIPTION
[0021] The technical solution of the present invention will be described in detail below in conjunction with specific embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present invention.
[0022] A high orbital flow / strong spin-orbit coupling thin film heterojunction is a "high orbital flow thin film / strong spin-orbit coupling thin film" heterostructure formed by a thin film with huge orbital flow and a thin film with strong spin-orbit coupling grown on a substrate; in the heterojunction thin film system, the bottom layer is a thin film layer with huge orbital flow, with a thickness of 10 to 120 nm, and the upper layer is a thin film layer with strong spin-orbit coupling, with a thickness of 0.5 to 2.0 nm; wherein the ratio of the thickness of the thin film layer with huge orbital flow to the thickness of the thin film layer with strong spin-orbit coupling is greater than 10:1.
[0023] A spin electronic device includes a substrate, a high orbital flow / strong spin-orbit coupling thin film heterojunction formed on the substrate, and a magnetic film layer or an antiferromagnetic film layer formed on the high orbital flow / strong spin-orbit coupling thin film heterojunction. The strong spin-orbit coupling thin film layer forms an interface contact with the magnetic layer. The high orbital flow thin film layer is used to generate a large orbital flow, which is converted into a huge spin flow through the strong spin-orbit coupling thin film layer. The spin flow enters the adjacent magnetic film layer and achieves efficient reversal of the adjacent magnetic moment through the spin-orbit torque. After testing, the current density of the current reversal magnetic moment of the "high orbital flow film / strong spin-orbit coupling film" heterojunction in the embodiment at room temperature is reduced to 5.7×10 5 A / cm 2 , which is 10 times higher than that of a single strong spin-orbit coupling film (such as Pt). 7 A / cm 2 It has been reduced by nearly two orders of magnitude.
[0024] Example
[0025] A method for preparing a high orbital flow / strong spin-orbit coupling thin film heterojunction specifically comprises the following steps:
[0026] S1. Loading high-purity giant orbital Hall effect titanium (Ti) target and high-purity strong spin-orbit coupling platinum (Pt) target into the target position of the magnetron sputtering equipment cavity;
[0027] S2, using a surface thermally oxidized Si substrate as a substrate, cleaning it with acetone, alcohol and deionized water, and drying it with nitrogen to ensure that the surface of the Si substrate is clean;
[0028] S3, placing the substrate cleaned in step S2 into a magnetron sputtering device to grow "Ti(d Ti nm) / Pt(1nm)” thin film heterojunction, the specific process is:
[0029] (1) In 2×10 -5 Under a background vacuum of 1.5 Pa, argon gas was introduced into the vacuum chamber at a flow rate of 20 Sccm until the pressure stabilized to 0.27-0.32 Pa;
[0030] (2) Under an argon pressure of 0.27-0.32 Pa, turn on the magnetron sputtering power supply, pre-sputter each target for 10 minutes at a DC power of 30 W, and use argon ion bombardment to clean the target surface to ensure that impurities such as the oxide layer on the target surface are completely removed;
[0031] (3) Open the target baffle and sputter Ti (10W) and Pt (5W) respectively. After reaching the set growth time, close the target baffle and sputtering power supply to obtain Ti (d Ti nm) / Pt(1nm) thin film heterojunction;
[0032] The present invention uses spin-orbit torque to drive the ferromagnetic resonance of nickel-iron (Py) nanofilm to evaluate the equivalent orbital Hall angle, and changes the thickness of different Ti nanolayers d Ti ,like Figure 1 As shown, we get Ti(d Ti The law of the spin-orbit torque generation efficiency ξ of Ti(d Ti When Ti is 120nm in the Ti(120nm) / Pt(1nm) heterojunction material, the spin-orbit torque generation efficiency tends to saturation, and the spin-orbit torque generation efficiency ξ reaches 2.541±0.668. We calculate that the magnetic moment reversal efficiency η in the Ti(120nm) / Pt(1nm) / Py system is 3.094±0.044.
[0033] In order to verify the efficiency of current reversal of magnetic moment in heterojunction film, a 1nm thick magnetic Co film was grown on Ti(120nm) / Pt(1nm) film heterojunction by S3 preparation process to form Ti(120nm) / Pt(1nm) / Co(1nm) multilayer film. The multilayer film was processed into a micro Hall device by photolithography process. A 15mA pulse current (pulse width) was applied to the device. The spin current generated by Ti(120nm) / Pt(1nm) heterojunction was injected into the magnetic layer Co film. The current reversal of magnetic moment in Co film was realized by spin-orbit torque. The current density of magnetic moment reversal of Co by Ti(120nm) / Pt(1nm) heterojunction film was calculated to be 5.7×10 5 A / cm 2 (like Figure 2This value is nearly two orders of magnitude lower than that of single Pt material, comparable to topological insulator films, and can be grown on a large area using simple processes such as magnetron sputtering. It is compatible with semiconductor CMOS processes. The heterojunction system of the present invention can be applied to the development of low-power spin logic chips.
[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.
Claims
1. A high orbital flow / strong spin-orbit coupling thin film heterojunction, characterized in that: The thin film heterojunction comprises a high orbital flow film and a strong spin-orbit coupling film sequentially grown on a substrate, the thickness of the high orbital flow film is 10 to 120 nm, and the thickness of the strong spin-orbit coupling film is 0.5 to 2 nm; wherein the thickness ratio of the high orbital flow film to the strong spin-orbit coupling film is greater than 10:
1.
2. The high orbital flow / strong spin-orbit coupling thin film heterojunction according to claim 1, characterized in that: The high orbital flow film is Ti, V, Cr, Mn and alloys thereof.
3. The high orbital flow / strong spin-orbit coupling thin film heterojunction according to claim 1, characterized in that: The strong spin-orbit coupling film is W, Pt, Ta or Bi2Te3.
4. The high orbital flow / strong spin-orbit coupling thin film heterojunction according to claim 1, characterized in that: The substrate is a silicon wafer or a sapphire substrate with a thermally oxidized surface.
5. The high orbital flow / strong spin-orbit coupling thin film heterojunction according to claim 1, characterized in that: The high orbital flow film and the strong spin-orbit coupling film are grown on a substrate by physical vapor deposition or magnetron sputtering.
6. The high orbital flow / strong spin-orbit coupling thin film heterojunction according to claim 1, characterized in that: The preparation process of the high orbital flow / strong spin-orbit coupling thin film heterojunction is as follows: -5 Pa, argon gas is introduced into the vacuum chamber at a flow rate of 20 Sccm, and the magnetron sputtering power supply is turned on after the gas pressure stabilizes to 0.27-0.32 Pa, and each target material is pre-sputtered for 10 minutes with a DC power of 30 W; after the pre-sputtering is completed, the target material baffle is opened for coating, and the thin film material with high orbital flow is first grown with a power of 10 W, and then the thin film material with strong spin-orbit coupling is grown with a power of 5 W; after the set growth time is reached, the target material baffle and the sputtering power supply are turned off to obtain a high orbital flow / strong spin-orbit coupling thin film heterojunction.
7. A spin electronic device, characterized in that: It includes a substrate, a high orbital flow / strong spin-orbit coupling thin film heterojunction formed on the substrate, and a magnetic film layer or an antiferromagnetic film layer formed on the high orbital flow / strong spin-orbit coupling thin film heterojunction; wherein, in the high orbital flow / strong spin-orbit coupling thin film heterojunction, the thickness of the high orbital flow layer is 10 to 120 nm, and the thickness of the strong spin-orbit coupling layer is 0.5 to 2.0 nm.
8. The spintronic device according to claim 7, characterized in that: The magnetic film layer is Co, CoFe, NiFe, CoFeB or Y3Fe5O 12 The antiferromagnetic thin film layer is IrMn, Mn3Sn, NiO or CrO2.
9. The spintronic device according to claim 7, characterized in that: By testing the spin torque-ferromagnetic resonance voltage of high orbital flow / strong spin-orbit coupling thin film heterojunctions of different thicknesses, the spin-orbit torque generation efficiency of high orbital flow / strong spin-orbit coupling thin film heterojunctions is obtained by fitting.