Membrane stack for manufacturing spintronics device and magnetron sputtering equipment and method for manufacturing spintronics device

Abstract

The invention discloses a film stack for manufacturing a spintronics device and magnetron sputtering equipment and method of the spintronics device, and relates to the technical field of ultrahigh vacuum coating equipment.The film stack comprises a vacuum cavity and a multi-dimensional sample table arranged on the vacuum cavity, and the multi-dimensional sample table comprises a sample support used for bearing a sample; the adjusting assembly is used for driving the sample support to rotate and driving the sample support to rotate around the direction parallel to the central axis of the sample support; and the differential rotation drive is used for driving the sample support to radially rotate around the central shaft of the sample support. A dip angle rotation drive and a sample rotation drive are arranged on the multi-dimensional sample table, power transmission is carried out through a series of bevel gears, straight gears and gear shafts, autorotation and inclination of the sample support are achieved, lifting and rotation of the sample support are achieved under the action of the lifting module and differential rotation drive, different sputtering angles can be achieved, and the sputtering efficiency is improved. And high performance and high quality of different film layers are realized.

Description

Technical Field

[0001] This invention relates to the field of ultra-high vacuum coating equipment technology, specifically to magnetron sputtering equipment and methods for fabricating film stacks and devices for spintronic devices. Background Technology

[0002] The spin-orbit torque effect provides a core mechanism for realizing next-generation high-speed, low-power magnetic memories. Traditional SOT devices, such as Ta / CoFeB / MgO or Pt / Co / Pt magnetic multilayer films, exhibit symmetry in their current-induced magnetization reversals. An external in-plane magnetic field is required to break this symmetry and determine the direction of the magnetization reversal. This requirement severely hinders the practical application and high-density integration of SOT devices.

[0003] The existing products have the following defects during the processing: 1. Adding an external magnetic field coil or permanent magnet increases the complexity and power consumption of the device; 2. Providing an independent local magnetic field for each storage cell is extremely difficult to achieve in terms of manufacturing process. Summary of the Invention

[0004] The purpose of this invention is to provide a magnetron sputtering apparatus and method for fabricating spintronic devices, thereby achieving a deterministic SOT magnetization reversal method for fabricating spintronic devices without the assistance of an external magnetic field. This method, through the design of a multi-dimensional sample stage, introduces a controllable tilt angle into standard processes, resulting in a simple process with strong versatility.

[0005] The objective of this invention can be achieved through the following technical solutions: A magnetron sputtering apparatus for fabricating spintronic devices, comprising a vacuum chamber and a multidimensional sample stage disposed thereon, wherein the multidimensional sample stage includes: Sample holder, used to hold samples; An adjustment component is used to drive the sample holder to rotate and to drive the sample holder to circumferentially rotate about a direction parallel to its own central axis; A differential rotation drive is used to drive the sample holder to rotate radially about its central axis.

[0006] As a further aspect of the present invention, the multidimensional sample stage also includes a lifting module mounted on a differential rotation drive, which is used to drive the sample holder to move along its central axis axial direction.

[0007] As a further aspect of the present invention: the adjustment component includes: A sample rotation drive is installed on the guide shaft flange above the lifting module. The sample rotation drive is connected to and drives the sample holder to rotate via a first transmission chain. An angle rotation drive is installed on the guide flange above the lifting module. The angle rotation drive is connected through a second transmission chain and drives the sample holder to tilt and swing about its direction parallel to the central axis.

[0008] As a further aspect of the present invention: the first transmission chain includes a second drive shaft, a first gear shaft, a first spur gear shaft, a second spur gear shaft, a first bevel gear shaft, and a spur gear coaxially arranged with the sample holder, which are meshed and transmitted in sequence.

[0009] As a further aspect of the present invention: the second transmission chain includes a first drive shaft, a second gear shaft, a second bevel gear shaft, and a large bevel gear arranged perpendicular to the sample holder, which mesh and transmit power in sequence.

[0010] As a further aspect of the present invention: a support plate is installed in the vertical direction of the large bevel gear, and a spur gear is rotatably connected to the bottom of the support plate. The lower surface of the spur gear is connected to the sample holder through a connecting rod. A heating device is fixedly installed on the lower surface of the support plate.

[0011] As a further aspect of the present invention: the large bevel gear is in the shape of a semi-bevel gear and is driven by a second transmission chain to oscillate around its radial axis.

[0012] As a further aspect of the present invention: the angle of the tilt swing is from -45 degrees to 45 degrees.

[0013] As a further aspect of the present invention: the multidimensional sample stage also includes a transition flange fixed on the vacuum chamber, and the transition flange is provided with a differential rotation drive, which is composed of a worm gear.

[0014] As a further aspect of the present invention: a method for fabricating a spintronic device film stack and the device specifically includes the following steps: S1. The cleaned substrate is transferred into the vacuum chamber of the magnetron sputtering equipment and fixed on the sample holder of the multidimensional sample stage; S2. In the vacuum chamber, the multidimensional sample stage is adjusted to drive the sample holder to rotate, circumferentially rotate, tilt and rise and fall, and to deposit a multilayer film stack including at least a heavy metal layer, a magnetic layer and an oxide protective layer in sequence. S3. Under vacuum conditions, start the heating device to anneal the substrate with deposited film stacks; S4. The annealed substrate is removed, and the device pattern is defined on the film stack through photolithography and etching processes. Then, electrodes are fabricated to obtain a spintronic device.

[0015] The beneficial effects of this invention are: This invention features a tilt rotation drive and a sample rotation drive on a multi-dimensional sample stage. Power is transmitted through a series of bevel gears, spur gears, and gear shafts to achieve the rotation and tilting of the sample holder. Under the action of a lifting module and a differential rotation drive, the sample holder is lifted and rotated, enabling different sputtering angles to achieve high performance and high quality for different film layers. It introduces controllable film quality and thickness gradients, achieves deterministic magnetic field-free reversal, fundamentally eliminates dependence on external magnetic fields, simplifies device structure and circuit design, and ensures that all motion functions are realized in an ultra-high vacuum environment, meeting the requirements for high-quality film preparation.

[0016] In the sputtering step of this invention, the tiltable sample stage can be angled with the sputtering cathode to perform sputtering, thereby creating a multi-layer quality and thickness stacking gradient. This gradient causes a gradient distribution of the diffusion degree of heavy metal atoms into the magnetic layer during subsequent annealing, or induces a gradient interface quality at the interface, thus generating an equivalent built-in field in the magnetic layer, breaking the symmetry of SOT flipping and achieving deterministic flipping without a field. Attached Figure Description

[0017] The invention will now be further described with reference to the accompanying drawings.

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the overall structure of the multidimensional sample stage of the present invention; Figure 3 This is a front view schematic diagram of the multidimensional sample stage of the present invention; Figure 4 This is a partial structural schematic diagram of the adjustment component of the present invention; Figure 5 This is a schematic diagram of the overall structure of the rotary drive of the present invention; Figure 6 This is a schematic diagram of the overall structure of the sample holder and heating device of the present invention; Figure 7 This is a schematic diagram of the swing structure of the sample holder of the present invention; Figure 8 This is a test schematic diagram of Embodiment 2 of the present invention; Figure 9 This is a test schematic diagram of Embodiment 3 of the present invention; Figure 10 This is a test schematic diagram of Embodiment 4 of the present invention.

[0019] In the diagram: 1. Vacuum chamber; 2. Observation window; 3. Magnetron sputtering cathode; 4. Vacuum measurement module; 5. Pressure control valve; 6. Vacuum pump; 7. Multidimensional sample stage; 71. Adapter flange; 72. Differential rotary drive; 73. Lifting module; 74. Connecting flange; 75. Guide shaft flange; 76. Sample rotation drive; 77. Tilt rotation drive; 78. First drive shaft; 79. Second drive shaft; 701. First gear shaft; 702. Second gear shaft; 703. Fixing base; 704. First spur gear shaft; 705. Second spur gear shaft; 706. First bevel gear shaft; 707. Spur gear; 708. Sample holder; 709. Second bevel gear shaft; 710. Large bevel gear; 711. Support plate; 712. Bearing; 713. Heating device. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1 Please see Figure 1 As shown, the present invention is a film stack for fabricating spintronic devices and a magnetron sputtering device, including a vacuum chamber 1, an observation window 2, a magnetron sputtering cathode 3, a vacuum measurement module 4, a pressure control valve 5, a vacuum pump 6, and a multidimensional sample stage 7. Vacuum chamber 1 is an ultra-high vacuum sealed chamber made of 304 stainless steel with low vacuum outgassing rate. It features all-metal CF sealed knife-edge interfaces on the top, bottom, left, right, front, and back for connecting different components. An observation window 2, made of quartz glass, is installed at the front for real-time observation of the internal sample and heating status during vacuum deposition. Several CF interfaces are evenly distributed at the bottom of vacuum chamber 1 for mounting magnetron sputtering cathodes 3, serving as connection points for the core components of thin film deposition. Each flange is distributed at a 30-degree angle relative to the axis of the vacuum chamber, converging at a single point within the chamber as the intersection point for the thin film sputtering position. A vacuum measurement module 4 is installed on the left rear side of vacuum chamber 1 to detect the internal vacuum state, ranging from standard atmospheric pressure to ultra-high vacuum pressures of 1E-7 Pa. A pressure control valve 5 and a vacuum pump 6 are sequentially connected at the rear of vacuum chamber 1. The pressure control valve 5 is a butterfly valve; by changing the cross-sectional area of ​​the vacuum pump 6 and the vacuum chamber 1's extraction pipe, the internal pressure of vacuum chamber 1 is controlled to achieve ideal process pressure conditions. Vacuum pump 6 is installed immediately after pressure control valve 5 to extract molecules from the vacuum chamber 1 to create a vacuum environment. Before starting the vacuuming process, all flanges and windows must be inspected to ensure that all connections are properly sealed. Generally, a roughing pump is connected to the molecular pump pre-portion or the pre-reserved interface in the vacuum chamber to obtain a rough vacuum. When the vacuum gauge reading reaches the molecular pump's starting pressure, the molecular pump is started to achieve the required vacuum level in the vacuum chamber. In this embodiment, refer to Figure 1-3 As shown, a multi-dimensional sample stage 7 is installed on the vacuum chamber 1. The multi-dimensional sample stage 7 allows for various adjustments to meet the high requirements of thin film preparation. The multi-dimensional sample stage 7 includes a transition flange 71, a differential rotation drive 72, a lifting module 73, a connecting flange 74, a guide shaft flange 75, a sample rotation drive 76, a tilt rotation drive 77, a first drive shaft 78, and a second drive shaft 79. The transition flange 71 is a flange with two reducing diameters; one end has a CF200 interface for a sealed connection to the vacuum chamber 1, and the other end has a CF150 interface for connection to the differential rotation drive. The differential rotary drive 72 is a precision moving component designed to reduce vacuum leakage and meet high load requirements. Its principle is to allow a rotating shaft to rotate continuously between ultra-high vacuum chambers, isolating atmospheric or pre-vacuum contaminants outside the vacuum chamber. Its lower flange is fixed, while the upper flange is rotating. The component fixed to the upper flange can rotate periodically to drive the sample holder 708 to rotate radially around its central axis. The differential rotary drive 72 is composed of a worm gear, which drives the entire multi-dimensional sample stage 7 to rotate periodically through the transmission of the worm gear.

[0022] A differential rotary drive 72 has a lifting module 73 mounted on its rotating flange. This module enables a high-precision, leak-free, and long-life reciprocating motion displacement unit in the vertical direction within a vacuum environment. The displacement distance is 0~100mm. The lifting module 73 includes a motor mounting bracket on which a lifting motor is fixedly mounted. The lifting motor drives a vertically positioned lead screw to rotate. The lead screw is connected to a bellows via a threaded sleeve. The lower end of the bellows is connected to the rotating flange, and the upper end is connected to a knife-edge flange. A connecting flange 74 is fixedly mounted on the knife-edge flange. A guide shaft flange 75 is mounted on the adapter flange 71. The guide shaft flange 75 extends into the vacuum chamber 1. The bottom of the guide shaft flange 75 is bolted to a fixing seat 703 for mounting other components. A sample adjustment assembly is fixedly mounted on the guide shaft flange 75 to drive the sample holder to rotate radially around its own central axis and to rotate axially around its central axis. By starting the drive motor, the lead screw rotates, which in turn causes the bellows to rise and fall, and in turn causes the adjustment component structure above it to rise and fall.

[0023] In this embodiment, the adjustment assembly includes a sample rotation drive 76 and a tilt rotation drive 77. The sample rotation drive 76 is fixed at the top center of the guide shaft flange 75, and the tilt rotation drive 77 is tilted at the top of the guide shaft flange 75. The sample rotation drive 76 is connected to and drives the sample holder 708 to rotate radially around its own central axis through a first transmission chain. The tilt rotation drive 77 is connected to and drives the sample holder 708 to tilt and swing about an angle parallel to its central axis through a second transmission chain. The sample rotation drive 76 and the tilt rotation drive 77 are both drive motors.

[0024] In this embodiment, refer to Figure 4-6As shown, the multidimensional sample stage 7 also includes a first gear shaft 701, a second gear shaft 702, a fixed base 703, a first spur gear shaft 704, a second spur gear shaft 705, a first bevel gear shaft 706, a spur gear 707, a sample holder 708, a second bevel gear shaft 709, a large bevel gear 710, a support plate 711, a bearing 712, and a heating device 713. A second drive shaft 79 is fixedly mounted on the bottom of the sample rotation drive 76. The second drive shaft 79 passes through a guide flange 75 and has a bevel gear mounted on its bottom. The bevel gear at the bottom of the second drive shaft 79 meshes with the left gear of the first gear shaft 701 for 90-degree torque transmission to the right spur gear. The right spur gear of the first gear shaft 701 meshes with the spur gear on the first spur gear shaft 704 mounted on the fixed base 703. The spur gear on the first spur gear shaft 704 meshes with the spur gear on the lower second spur gear shaft 705 for transmission. A bevel gear is installed on the left side of the second spur gear shaft 705. A large bevel gear 710 is also connected to the second spur gear shaft 705 via a bearing. A vertically arranged support plate 711 is bolted to the left side plane of the large bevel gear 710. A bearing 712 is installed at the lower part of the support plate 711. A spur gear 707 is installed in the mounting hole of the outer ring of the bearing 712 and can rotate freely. The bottom of the spur gear 707 is connected to the sample holder 708 via a connecting rod. The upper surface of the support plate 711 is vertically mounted with a first bevel gear shaft 706. A bevel gear matching the bevel gear placed on the left side of the second spur gear shaft 705 is fixedly mounted on the bottom of the first bevel gear shaft 706. A small spur gear is also mounted on the first bevel gear shaft 706. The small spur gear meshes with the spur gear 707 to drive the sample holder 708 to rotate.

[0025] Specifically, the sample rotation drive 76 is activated, which drives the first gear shaft 701 to rotate via the second drive shaft 79, and then drives the first spur gear shaft 704 and the second spur gear shaft 705 to rotate in sequence. The second spur gear shaft 705 drives the second spur gear shaft 705 to rotate, which in turn drives the spur gear 707 to rotate via the small spur gear, and then drives the sample holder 708 to rotate.

[0026] In this embodiment, refer to Figure 3As shown, the bottom of the tilting rotation drive 77 is connected to the first drive shaft 78 via a universal joint. The bevel gear mounted at the bottom of the first drive shaft 78 meshes with the left bevel gear of the second gear shaft 702 to form a 90-degree transmission. The right bevel gear of the second gear shaft 702 meshes with the upper bevel gear of the second bevel gear shaft 709 for transmission. The lower gear of the second bevel gear shaft 709 meshes with the large bevel gear 710 to drive its rotation, while simultaneously driving the heating device 713 and the sample holder 708 to rotate as a whole around the center fulcrum of the large bevel gear 710. The large bevel gear 710 is coaxially mounted on the fixed seat 703 via bearings and can rotate radially. Its shape is a half bevel gear. A support plate 711 is fixedly installed on one side of the large bevel gear 710. A heating device 713 is fixedly installed on the lower surface of the support plate 711. The heating device 713 is fixed on the support plate 711 and cannot be rotated or displaced. The heating device 713 has a cylindrical structure. The sample holder 708 is located below the heating device 713 and is used to heat the sample surface.

[0027] Specifically, the tilt rotation drive 77 is activated, which drives the first drive shaft 78 to rotate. The first drive shaft 78 drives the second gear shaft 702 to rotate, which in turn drives the second bevel gear shaft 709 to rotate. The second bevel gear shaft 709 drives the large bevel gear 710 to rotate, and the large bevel gear 710 drives the support plate 711 to rotate, which in turn drives the heating device 713 and the sample holder 708 to swing.

[0028] In summary, the overall structure consists of a differential rotation drive 72 that drives the sample holder 708 to rotate along the vertical axis, a lifting module 73 that controls the overall lifting and lowering movement of the heating device 713 and the sample holder 708, a sample rotation drive 76 that drives the sample holder 708 to rotate continuously in the circumference, and a tilt rotation drive 77 that controls the heating device 713 and the sample holder 708 to rotate at -45 to +45 degrees along the horizontal axis. (See reference...) Figure 7 As shown.

[0029] In practical implementation, the magnetron sputtering cathode 3 installed on the vacuum chamber 1 has a fixed angle and distance, and the convergence point of its pointing angle is also fixed. Therefore, a multi-dimensional sample stage 7 is needed to achieve various adjustments to meet the high requirements of thin film preparation. To this end, the multi-dimensional sample stage 7 is equipped with sample holder lifting, rotation, tilting, and self-rotation functions to adjust the thin film deposition rate and uniformity. It also has a heating function to improve the crystallinity, density, and mechanical properties of the thin film.

[0030] Process steps: In traditional SOT (spin-optical material) film stacks and fabrication methods, achieving current-driven magnetization reversal requires an in-plane magnetic field. By using an adjustable-angle sample stage, magnetization reversal can be achieved at the device level without the need for an in-plane magnetic field. This approach helps improve the fabrication and process flow of SOT-based spintronic devices. The following are the specific implementation methods: A method for fabricating a spin-orbit torque film stack and device with perpendicular magnetic anisotropy and field-free reversal capability, taking a Pt / CoFeB / MgO film stack and device as an example, includes the following specific steps: Example 2: S1. After ultrasonically cleaning the single-crystal Si substrate with alcohol, place it in the sample transfer chamber. Wait until the sample transfer chamber and sputtering chamber are within two orders of magnitude of each other, then use the sample transfer system to transfer the substrate to the sample position on the sample holder 708. When the vacuum environment of the chamber meets the sputtering requirements (≤5×10⁻⁶), the substrate is then transferred to the sample position on the sample holder 708. -6 At Pa), Pt, CoFeB and MgO films are sputtered sequentially. S2. When sputtering is used to provide a heavy metal layer Pt for SOT spin flow, it is controlled by a sample stage lifting motor. The sample stage height is 30mm, the tilt angle is +30°, the rotation speed is 90° / s, the DC power supply sputtering power is 30W, the sputtering gas pressure is 0.5Pa, and the Pt thickness is 5nm. S3. Sputtering is used to achieve a magnetic CoFeB layer with magnetization reversal and perpendicular anisotropy. It is controlled by a sample stage lifting motor. The sample stage height is 50 mm, the tilt angle is 0°, the rotation speed is 120° / s, and a DC power supply is used for sputtering with a power of 20 W and a sputtering gas pressure of 0.5 Pa. The CoFeB thickness is 1 nm. S4. Sputtering for the protective MgO layer: Sputtering is performed using an RF power supply and controlled by a sample stage lifting motor. The sample stage height is 20 mm, the tilt angle is -45°, the rotation speed is 90° / s, the power is 60 W, the sputtering pressure is 1 Pa, and the MgO thickness is 2 nm. S5. Turn on the sample stage heating function and anneal in situ at 300℃ for 20 minutes. S6. Transfer the coated substrate to a clean room and clean it ultrasonically with alcohol; S7. Spin coat the photoresist onto the substrate surface, first spin coat slowly for 3s at a speed of 450 rad / min, then spin coat at high speed for 17s at a speed of 4000 rad / min; S8. Place the substrate on the baking tray and bake at 100°C for 22 seconds to remove impurities; S9. Place the substrate under a UV lithography machine and expose it to UV light for 8 seconds to transfer the Hallbar pattern onto the photoresist. S10. Transfer the exposed substrate to the developer and develop for 8 seconds; S11. Transfer the developed sample to the argon ion etching machine, place it on the etching stage, and turn on the vacuum pump group to make the vacuum environment in the chamber meet the etching requirements. S12. Turn on the etching stage rotation function, turn on the ion source, etching current 15A, etching time 270s; S13. Transfer the etched substrate to a clean room and repeat process 7-10 to transfer the electrode pattern onto the photoresist; S14. Transfer the substrate with electrodes and Hallbar pattern to the sample position to be coated below the sample stage of the magnetron sputtering cavity; S15. Sputtered Ti / Au composite electrode, DC power supply sputtering power 30W, sputtering gas pressure 0.5Pa, Ti thickness 10nm, Au thickness 100nm; S16. Remove the substrate and ultrasonically clean away the residual photoresist with alcohol to obtain a complete SOT device pattern that can be used for field-free flipping; S17. The anomalous Hall curve of the SOT device can be measured using an electrical transport measurement system, and the anomalous Hall voltage value ΔRHall can be obtained; S18. Use an electrical transport measurement system to perform current-driven field-free flip-flop testing on SOT devices, i.e., during the test, do not apply an in-plane magnetic field in the X direction to the device; Get as Figure 8 The curve shape shown indicates that SOT devices cannot achieve field-free switching.

[0031] Example 3: S1. After ultrasonically cleaning the single-crystal Si substrate with alcohol, place it in the sample transfer chamber. Wait until the sample transfer chamber and sputtering chamber are within two orders of magnitude of each other, then use the sample transfer system to transfer the substrate to the sample position on the sample holder 708. When the vacuum environment of the chamber meets the sputtering requirements (≤5×10⁻⁶), the substrate is then transferred to the sample position on the sample holder 708. -6 At Pa), Pt, CoFeB and MgO films are sputtered sequentially. S2. When sputtering is used to provide a heavy metal layer Pt for SOT spin flow, it is controlled by a sample stage lifting motor. The sample stage height is 30mm, the tilt angle is +30°, the rotation speed is 90° / s, the DC power supply sputtering power is 30W, the sputtering gas pressure is 0.5Pa, and the Pt thickness is 5nm. S3. Sputtering is used to achieve a magnetic CoFeB layer with magnetization reversal and perpendicular anisotropy. It is controlled by a sample stage lifting motor. The sample stage height is 50 mm, the tilt angle is +20°, the rotation speed is 120° / s, and a DC power supply is used for sputtering with a power of 20 W and a sputtering gas pressure of 0.5 Pa. The CoFeB thickness is 1 nm. S4. Sputtering for the protective MgO layer: Sputtering is performed using an RF power supply and controlled by a sample stage lifting motor. The sample stage height is 20 mm, the tilt angle is -45°, the rotation speed is 90° / s, the power is 60 W, the sputtering pressure is 1 Pa, and the MgO thickness is 2 nm. S5. Turn on the sample stage heating function and anneal in situ at 300℃ for 20 minutes. S6. Transfer the coated substrate to a clean room and clean it ultrasonically with alcohol; S7. Spin coat the photoresist onto the substrate surface, first spin coat slowly for 3s at a speed of 450 rad / min, then spin coat at high speed for 17s at a speed of 4000 rad / min; S8. Place the substrate on the baking tray and bake at 100°C for 22 seconds to remove impurities; S9. Place the substrate under a UV lithography machine and expose it to UV light for 8 seconds to transfer the Hallbar pattern onto the photoresist. S10. Transfer the exposed substrate to the developer and develop for 8 seconds; S11. Transfer the developed sample to the argon ion etching machine, place it on the etching stage, and turn on the vacuum pump group to make the vacuum environment in the chamber meet the etching requirements. S12. Turn on the etching stage rotation function, turn on the ion source, etching current 15A, etching time 270s; S13. Transfer the etched substrate to a clean room and repeat process 7-10 to transfer the electrode pattern onto the photoresist; S14. Transfer the substrate with electrodes and Hallbar pattern to the sample position to be coated below the sample stage of the magnetron sputtering cavity; S15. Sputtered Ti / Au composite electrode, DC power supply sputtering power 30W, sputtering gas pressure 0.5Pa, Ti thickness 10nm, Au thickness 100nm; S16. Remove the substrate and ultrasonically clean away the residual photoresist with alcohol to obtain a complete SOT device pattern that can be used for field-free flipping; S17. The anomalous Hall curve of the SOT device can be measured using an electrical transport measurement system, and the anomalous Hall voltage value ΔRHall can be obtained; S18. Use an electrical transport measurement system to perform current-driven field-free flip-flop testing on SOT devices, i.e., during the test, do not apply an in-plane magnetic field in the X direction to the device; Get as Figure 9 The curve shape shown can achieve field-free SOT magnetization reversal curve.

[0032] Example 4 S1. After ultrasonically cleaning the single-crystal Si substrate with alcohol, place it in the sample transfer chamber. Wait until the sample transfer chamber and sputtering chamber are within two orders of magnitude of each other, then use the sample transfer system to transfer the substrate to the sample position on the sample holder 708. When the vacuum environment of the chamber meets the sputtering requirements (≤5×10⁻⁶), the substrate is then transferred to the sample position on the sample holder 708. -6 At Pa), Pt, CoFeB and MgO films are sputtered sequentially. S2. When sputtering is used to provide a heavy metal layer Pt for SOT spin flow, it is controlled by a sample stage lifting motor. The sample stage height is 30mm, the tilt angle is +30°, the rotation speed is 90° / s, the DC power supply sputtering power is 30W, the sputtering gas pressure is 0.5Pa, and the Pt thickness is 5nm. S3. Sputtering is used to achieve a magnetic CoFeB layer with magnetization reversal and perpendicular anisotropy. It is controlled by a sample stage lifting motor. The sample stage height is 50 mm, the tilt angle is +45°, the rotation speed is 120° / s, and a DC power supply is used for sputtering with a power of 20 W and a sputtering gas pressure of 0.5 Pa. The CoFeB thickness is 1 nm. S4. Sputtering for the protective MgO layer: Sputtering is performed using an RF power supply and controlled by a sample stage lifting motor. The sample stage height is 20 mm, the tilt angle is -45°, the rotation speed is 90° / s, the power is 60 W, the sputtering pressure is 1 Pa, and the MgO thickness is 2 nm. S5. Turn on the sample stage heating function and anneal in situ at 300℃ for 20 minutes. S6. Transfer the coated substrate to a clean room and clean it ultrasonically with alcohol; S7. Spin coat the photoresist onto the substrate surface, first spin coat slowly for 3s at a speed of 450 rad / min, then spin coat at high speed for 17s at a speed of 4000 rad / min; S8. Place the substrate on the baking tray and bake at 100°C for 22 seconds to remove impurities; S9. Place the substrate under a UV lithography machine and expose it to UV light for 8 seconds to transfer the Hallbar pattern onto the photoresist. S10. Transfer the exposed substrate to the developer and develop for 8 seconds; S11. Transfer the developed sample to the argon ion etching machine, place it on the etching stage, and turn on the vacuum pump group to make the vacuum environment in the chamber meet the etching requirements. S12. Turn on the etching stage rotation function, turn on the ion source, etching current 15A, etching time 270s; S13. Transfer the etched substrate to a clean room and repeat process 7-10 to transfer the electrode pattern onto the photoresist; S14. Transfer the substrate with electrodes and Hallbar pattern to the sample position to be coated below the sample stage of the magnetron sputtering cavity; S15. Sputtered Ti / Au composite electrode, DC power supply sputtering power 30W, sputtering gas pressure 0.5Pa, Ti thickness 10nm, Au thickness 100nm; S16. Remove the substrate and ultrasonically clean away the residual photoresist with alcohol to obtain a complete SOT device pattern that can be used for field-free flipping; S17. The anomalous Hall curve of the SOT device can be measured using an electrical transport measurement system, and the anomalous Hall voltage value ΔRHall can be obtained; S18. Use an electrical transport measurement system to perform current-driven field-free flip-flop testing on SOT devices, i.e., during the test, do not apply an in-plane magnetic field in the X direction to the device; Get as Figure 10 The curve shape shown can achieve a partially field-free SOT magnetization reversal curve.

[0033] As can be seen from Examples 2-4 above, when using this method to fabricate spin-orbit torque film stacks and devices with perpendicular magnetic anisotropy and field-free reversal capability, the angle between the cathode and the adjustable sample stage can be customized during sputtering to achieve a gradient distribution in the SOT film stack. After annealing, a gradient interface quality is induced at the interface, thereby generating an equivalent built-in field in the magnetic layer, breaking the symmetry of SOT reversal and achieving deterministic reversal without a field. This approach helps improve the process and fabrication flow of SOT-based spintronic devices. This method constructs an intrinsic spin current gradient within the device using sputtering, thus achieving deterministic SOT magnetization reversal without external magnetic field assistance. Through a sophisticated sample stage design, a controllable tilt angle is introduced into the standard process without modifying the complex film stack structure or introducing special materials. It is fully compatible with existing semiconductor manufacturing processes, simple in process, and highly universal.

[0034] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A magnetron sputtering apparatus for fabricating spintronic devices, comprising a vacuum chamber and a multidimensional sample stage disposed thereon, characterized in that, The multidimensional sample stage includes: Sample holder, used to hold samples; An adjustment component is used to drive the sample holder to rotate and to drive the sample holder to circumferentially rotate about a direction parallel to its own central axis; A differential rotation drive is used to drive the sample holder to rotate radially about its central axis.

2. The magnetron sputtering apparatus for fabricating spintronic devices and the devices according to claim 1, characterized in that, The multidimensional sample stage also includes a lifting module mounted on a differential rotary drive, which is used to drive the sample holder to move along its central axis axial direction.

3. The magnetron sputtering apparatus for fabricating spintronic devices and the device according to claim 1, characterized in that, The adjustment component includes: A sample rotation drive is installed on the guide shaft flange above the lifting module. The sample rotation drive is connected to and drives the sample holder to rotate via a first transmission chain. An angle rotation drive is installed on the guide flange above the lifting module. The angle rotation drive is connected through a second transmission chain and drives the sample holder to tilt and swing about its direction parallel to the central axis.

4. The magnetron sputtering apparatus for fabricating spintronic devices and the devices according to claim 3, characterized in that, The first transmission chain includes a second drive shaft, a first gear shaft, a first spur gear shaft, a second spur gear shaft, a first bevel gear shaft, and a spur gear coaxially arranged with the sample holder, which mesh and transmit power in sequence.

5. The magnetron sputtering apparatus for fabricating spintronic devices and the devices according to claim 3, characterized in that, The second transmission chain includes a first drive shaft, a second gear shaft, a second bevel gear shaft, and a large bevel gear arranged perpendicular to the sample holder, which mesh and transmit power in sequence.

6. The magnetron sputtering apparatus for fabricating spintronic devices and the devices according to claim 5, characterized in that, A support plate is installed vertically on the large bevel gear, and a spur gear is rotatably connected to the bottom of the support plate. The lower surface of the spur gear is connected to the sample holder via a connecting rod. A heating device is fixedly installed on the lower surface of the support plate for heating the sample on the sample holder.

7. The magnetron sputtering apparatus for fabricating spintronic devices and the devices according to claim 6, characterized in that, The large bevel gear is in the shape of a semi-bevel gear and is driven by the second transmission chain to oscillate around its radial axis.

8. The magnetron sputtering apparatus for fabricating spintronic devices and the devices according to claim 7, characterized in that, The angle of the tilt swing is from -45 degrees to 45 degrees.

9. The magnetron sputtering apparatus for fabricating spintronic devices and the devices according to claim 1, characterized in that, The multidimensional sample stage also includes a transition flange fixed on the vacuum chamber, and a differential rotary drive is provided on the transition flange, which is composed of a worm gear.

10. A method for fabricating a thin film stack and a device for spintronic devices, characterized in that, The method of using the magnetron sputtering equipment for fabricating spintronic devices as described in claim 1 specifically includes the following steps: S1. The cleaned substrate is transferred into the vacuum chamber of the magnetron sputtering equipment and fixed on the sample holder of the multidimensional sample stage; S2. In the vacuum chamber, the multidimensional sample stage is adjusted to drive the sample holder to rotate, circumferentially rotate, tilt and rise and fall, and to deposit a multilayer film stack including at least a heavy metal layer, a magnetic layer and an oxide protective layer in sequence. S3. Under vacuum conditions, start the heating device to anneal the substrate with deposited film stacks; S4. The annealed substrate is removed, and the device pattern is defined on the film stack through photolithography and etching processes. Then, electrodes are fabricated to obtain a spintronic device.

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