Methods of making platinum-based high spin hall angle materials, alloy thin films, and applications

Abstract

The application provides a method for preparing a platinum-based high-spin Hall angle material, an alloy film and application, the method comprising: adding impurities to form an alloy film with a polycrystalline or single crystal structure by the impurities and platinum during the growth of a platinum-based metal film; wherein the impurities are one or more of a non-platinum metal, a metal carbide, a metal nitride or a metal oxide and silicon or a silicon compound; the volume percentage of the impurities is 1%-60%; the platinum in the platinum-based metal film is used to provide a spin Hall effect; and the impurities are used to enhance the electron scattering and resistivity of the platinum in the platinum-based metal film. The alloy film has the advantages of low resistivity, a large spin Hall angle, uniformity, low cost, stable structure and properties, compatibility with integrated circuits and CMOS semiconductor processes and the like. The magnetic random access memory, oscillator, logic device, raceway storage and computing device and the like developed based on the alloy film have the advantages of high energy efficiency, long service life, low impedance and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of information technology and integrated circuits, and in particular to a method for preparing a platinum-based high spin Hall angle material, an alloy film and applications. BACKGROUND

[0002] In recent years, information technology has made great progress, and the demand for high-speed information storage and transmission is increasing. Spin-orbit torque driven non-volatile storage, computing and sensing technologies are considered to be one of the most promising solutions in the "post-Moore era". The performance requirements of power consumption, speed, life and integration density of such applications require that the spin-orbit torque source material must have both high resistivity and high spin Hall angle. This is because high resistivity materials (such as topological insulators, strongly correlated oxides, beta-W and beta-Ta, etc.) will cause a large amount of driving current to diffuse into adjacent conductive layers, resulting in a substantial increase in total current, transistor size and Joule heat, which in turn affects the efficiency, life and integration density of the device. Therefore, low-impedance spin Hall metal Pt has become a star material in spintronics research, but the spin Hall angle of pure Pt is relatively low. How to prepare a thin film material with low impedance and high spin Hall angle has become a key problem for the industrialization of spin-orbit torque technology. SUMMARY

[0003] Based on this, the present application proposes a method for preparing a platinum-based high spin Hall angle material, an alloy film and applications, which simultaneously realizes low impedance and high spin Hall angle, and is expected to be applied to high-energy-efficient, long-life, low-impedance magnetic random access memory, logic devices, race track storage and computing devices, etc.

[0004] According to a first aspect of the present application, a method for preparing a platinum-based high spin Hall angle material is provided, comprising:

[0005] In the growth process of the platinum-based metal film, an impurity is added to form an alloy thin film with a polycrystalline or single crystal structure with the platinum;

[0006] The impurity is one or more of a metal other than platinum, a carbide of the metal, a nitride of the metal or an oxide of the metal, and silicon or a compound of silicon;

[0007] The volume percentage of the impurity is 1%-60%;

[0008] The platinum in the platinum-based metal film is used to provide a spin Hall effect;

[0009] The impurity is used to enhance the electron scattering and resistivity of the platinum in the platinum-based metal film.

[0010] According to an embodiment of the present application, the impurities are one or more of Si3N4, AlN, GaN, MgO, SiO2, ZnO, CdO, SnO2, Fe2O3, Cr2O3, Al2O3, SiC, Si, Ge, Mn, Pd, Ti, Cu, Cr.

[0011] According to an embodiment of the present application, the resistivity of the alloy thin film is no more than 120 micro-ohm centimeter.

[0012] According to an embodiment of the present application, the alloy thin film is grown by a deposition technique selected from the group consisting of magnetron sputtering, molecular beam epitaxy, thermal evaporation, ion beam evaporation, and laser pulse.

[0013] According to an embodiment of the present application, the alloy thin film is grown by a deposition technique selected from the group consisting of magnetron sputtering, including

[0014] The alloy thin film is grown by co-sputtering one or more targets containing the platinum and / or the impurities;

[0015] The flow rate of argon gas into the magnetron sputtering is 5-50 sccm.

[0016] The working pressure is 1-8 mTorr.

[0017] According to a second aspect of the present application, there is provided an alloy thin film prepared by the method described above.

[0018] According to a third aspect of the present application, there is provided an application of the alloy thin film described above as a carrier for information generation, processing, storage, and transmission in at least one of spin-orbit torque magnetic tunnel junction, spin Hall oscillator, and racetrack memory device.

[0019] According to an embodiment of the present application, there is provided:

[0020] The alloy thin film is combined with a magnetic thin film to form the carrier.

[0021] The carrier generates, processes, stores, and transmits information under the action of the spin-orbit torque generated by the alloy thin film.

[0022] According to an embodiment of the present application, the magnetic thin film contains one or more elements selected from the group consisting of Fe, Co, Ni, Cr, and Mn.

[0023] According to an embodiment of the present application, the thickness of the magnetic thin film is 0.2-50 nanometers.

[0024] As can be seen from the above technical solutions, the method for preparing a platinum-based high spin Hall angle material, the alloy thin film, and the application provided by the present application have the following beneficial effects:

[0025] The Pt-X alloy thin film prepared by the method has the advantages of polycrystalline or single crystal structure, low resistivity (≤120 mu Omega cm), huge spin Hall angle (up to 0.8), uniform and smooth (up to atomic level), low cost, stable structure and properties, compatible with integrated circuits and CMOS semiconductor processes and the like. The magnetic random access memory, oscillator, logic device, race track storage and computing device and the like based on the low impedance high spin Hall angle material have the advantages of high energy efficiency, long service life, low impedance and the like. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 Structure diagram of the Pt x X 1-x alloy thin film of the embodiment of the present application;

[0027] Figure 2 Spin Hall angle and spin-orbit torque of the Pt x X 1-x alloy thin film of the embodiment of the present application;

[0028] Figure 3 Resistivity of the Pt x (Si3N4) 1-x alloy thin film of the embodiment of the present application;

[0029] Figure 4 Surface morphology atomic force microscope image of the Pt x (Si3N4) 1-x alloy thin film of the embodiment of the present application;

[0030] Figure 5 High-resolution transmission electron microscope image of the Pt x (Si3N4) 1-x alloy thin film of the embodiment of the present application;

[0031] Figure 6 Spin-orbit torque efficiency of the Pt x (Si3N4) 1-x / Co 0.65 Tb 0.35 device of the embodiment of the present application;

[0032] Figure 7 Current flip chart of the Pt 0.7 (Si3N4) 0.3 / Co 0.65 Tb 0.35 device of the embodiment of the present application;

[0033] Figure 8 Structure diagram of the magnetic tunnel junction device and spin Hall oscillator core of the embodiment of the present application;

[0034] Figure 9 A schematic diagram of a racetrack memory device according to an embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to specific embodiments and drawings.

[0036] The power consumption, speed, life, integration density and other performance requirements of spin-orbit torque driven non-volatile storage, computing and sensing technologies require that the spin-orbit torque source material must have both resistivity and high spin Hall angle.

[0037] This is because high resistivity materials (such as topological insulators, strongly correlated oxides, beta-W and beta-Ta, etc.) will cause a large amount of driving current to diffuse into adjacent conductive layers, resulting in a substantial increase in total current, transistor size and Joule heat, which in turn affects the efficiency, life and integration density of the device.

[0038] Low-impedance spin Hall metal Pt has attracted much attention in spintronics. The spin Hall effect is a physical effect originating from spin-orbit related scattering of electrons, in which Fermi surface electrons are the carriers of spin. However, the spin Hall angle of pure Pt is relatively low. And the spin Hall conductivity of Pt is the largest among known conductors, and decreases nonlinearly with increasing resistivity, that is, the greater the resistivity, the faster the decrease.

[0039] Therefore, how to prepare a thin film material with low impedance and high spin Hall angle has become a key problem for the industrialization of spin-orbit torque technology.

[0040] According to the general inventive concept of the first aspect of the present application, a preparation method of a platinum-based high spin Hall angle material is provided, comprising:

[0041] During the growth of the platinum-based metal film, impurities are added to form an alloy thin film with a polycrystalline or single crystal structure by the impurities and platinum;

[0042] Among them, the impurities are one or more of non-platinum metals, metal carbides, metal nitrides or metal oxides, and silicon or silicon compounds;

[0043] The volume percentage of the impurities is 1%-60%;

[0044] The platinum in the platinum-based metal film is used to provide the spin Hall effect;

[0045] The impurities are used to enhance the electron scattering and resistivity of platinum in the platinum-based metal film.

[0046] The platinum (Pt) can form a Pt-X alloy with the impurity (X), can have a polycrystalline or single crystal structure, and preferably has a face-centered cubic structure in which Pt serves as a host material and provides a spin Hall effect, and X is used to enhance electron scattering and resistivity in the host Pt in a manner of impurity.

[0047] The Pt-X alloy thin film prepared by the method has a polycrystalline or single crystal structure, low resistivity (≤120 μΩcm), a large spin Hall angle (up to 0.8), uniform flatness (up to atomic level flatness), low cost, stable structure and properties, and is compatible with integrated circuit and CMOS semiconductor processes. The magnetic random access memory, oscillator, logic device, race track storage and computing device and other devices based on the low-impedance high-spin Hall angle material have high energy efficiency, long service life, low impedance and other advantages.

[0048] According to an embodiment of the present application, the impurity is one or more of Si3N4, AlN, GaN, MgO, SiO2, ZnO, CdO, SnO2, Fe2O3, Cr2O3, Al2O3, SiC, Si, Ge, Mn, Pd, Ti, Cu and Cr.

[0049] According to an embodiment of the present application, the resistivity of the alloy thin film is not greater than 120 μΩcm.

[0050] According to an embodiment of the present application, when the resistivity is 80-120 μΩcm, the spin Hall angle of the alloy thin film reaches a maximum value, up to 0.8.

[0051] According to an embodiment of the present application, the alloy thin film is grown and prepared based on a magnetron sputtering, molecular beam epitaxy, thermal evaporation, ion beam evaporation or laser pulse deposition technology.

[0052] According to an embodiment of the present application, the alloy thin film is grown and prepared based on a magnetron sputtering technology, including

[0053] The alloy thin film is grown by co-sputtering one or more targets containing platinum and / or impurity components;

[0054] The argon gas flow rate for the magnetron sputtering is 5-50 sccm;

[0055] The working gas pressure is 1-8 mTorr.

[0056] According to an embodiment of the present application, the argon gas flow rate for the magnetron sputtering can be 5 sccm, 10 sccm, 20 sccm, 30 sccm, 40 sccm or 50 sccm.

[0057] According to the embodiment of the present application, the working pressure can be 1 mTorr, 2 mTorr, 3 mTorr, 4 mTorr, 5 mTorr, 6 mTorr, 7 mTorr, 8 mTorr.

[0058] According to the embodiment of the present application, the growth process grows an adhesion layer and keeps the substrate rotating at a uniform speed, which can improve uniformity.

[0059] According to the embodiment of the present application, the alloy thin film can be grown on a substrate, which can be SiO2, Si3N4, MgO, Si, SiC, GaN, AlN, GaAs, quartz or sapphire.

[0060] According to the second aspect of the present application, an alloy thin film prepared by the above method is provided.

[0061] The Pt-X alloy thin film prepared by the method provided by the present application has the advantages of polycrystalline or single crystal structure, low resistivity (≤120 μΩcm), large spin Hall angle (up to 0.8), uniform and smooth (up to atomic level), low cost, stable structure and properties, compatible with integrated circuits and CMOS semiconductor processes, etc. Based on the low impedance high spin Hall angle material, the magnetic random access memory, oscillator, logic device, race track storage and computing device, etc. have the advantages of high energy efficiency, long service life, low impedance, etc.

[0062] Figure 1 The Pt x X 1-x alloy thin film of the embodiment of the present application.

[0063] As Figure 1 shown, in the Pt x X 1-x material, X is uniformly distributed in Pt as an impurity, so that the electrons in Pt receive higher intensity and more frequent collisions and scattering when moving under an electric field, thereby reducing the relaxation time of the electrons in Pt and increasing the resistivity of Pt, thereby regulating the spin Hall effect. Because the spin Hall effect is a physical effect originating from spin-orbit related scattering of electrons, in which the electrons on the Fermi surface are the carriers of spin. The spin Hall conductivity of Pt is the largest among known conductors, and decreases nonlinearly with the increase of resistivity, that is, the greater the resistivity, the faster the decrease.

[0064] Figure 2 The Pt x X 1-x material of the embodiment of the present application.

[0065] As Figure 2As shown, when the resistivity is in the range of 80-120 micro-ohm centimeter, the spin Hall angle of the material reaches a maximum (about 0.8), and the spin-orbit torque efficiency is generally less than the spin Hall angle which also reaches a maximum in this range. This is because the spin Hall angle is the product of the spin Hall conductivity and the resistivity, and the spin Hall conductivity decreases nonlinearly with the increase of the resistivity, and the two factors together cause the spin Hall angle to appear as Figure 2 a non-monotonic change relationship as shown, and reaches a maximum when the resistivity is in the range of 80-120 micro-ohm centimeter. The spin-orbit torque efficiency is positively correlated with the size of the spin Hall angle, but because the spin current is scattered during transmission, the spin-orbit torque efficiency is generally less than the spin Hall angle.

[0066] According to the third aspect of the overall inventive concept of the present application, an application of using the alloy thin film described above as a carrier for information generation, processing, storage and transmission in at least one of the following: spin-orbit torque magnetic tunnel junction, spin Hall oscillator, racetrack memory and computing device.

[0067] The Pt-X alloy thin film prepared by the method provided by the present application has the advantages of polycrystalline or single crystal structure, low resistivity (≤120 μΩcm), large spin Hall angle (up to 0.8), uniform and smooth (up to atomic level), low cost, stable structure and properties, and compatibility with integrated circuits and CMOS semiconductor processes. The magnetic random access memory, oscillator, logic device, racetrack memory and computing device based on the low-impedance high-spin Hall angle material have the advantages of high energy efficiency, long service life, low impedance, etc.

[0068] According to an embodiment of the present application, comprising:

[0069] The alloy thin film is combined with the magnetic thin film to form a carrier;

[0070] The carrier generates, processes, stores and transmits information under the action of the spin-orbit torque generated by the alloy thin film.

[0071] According to an embodiment of the present application, the magnetic thin film is located above or below the alloy thin film.

[0072] According to an embodiment of the present application, the magnetic thin film comprises one or more elements of Fe, Co, Ni, Cr and Mn.

[0073] According to an embodiment of the present application, the thickness of the magnetic thin film is 0.2-50 nanometers.

[0074] According to an embodiment of the present application, the thickness of the magnetic thin film can be 0.2, 1, 10, 20, 30, 40, 50 nanometers.

[0075] The technical solutions of the present application are described in detail below through preferred embodiments. It should be noted that the specific embodiments below are only used for illustration and do not limit the present application.

[0076] Example 1: Pt x (Si3N4) 1-x The alloy thin film sample is detected.

[0077] Figure 3 The Pt x (Si3N4) 1-x The resistivity of the alloy thin film changes with the composition.

[0078] Figure 4 The Pt x (Si3N4) 1-x The surface morphology atomic force microscope image of the alloy thin film.

[0079] Figure 5 The Pt x (Si3N4) 1-x The high-resolution transmission electron microscope image of the alloy thin film.

[0080] The alloy thin film is prepared by adding Si3N4 as an impurity in the growth process of the platinum-based metal film by using a magnetron sputtering technology, and the composition of the alloy thin film is Pt x (Si3N4) 1-x .

[0081] Figure 3 The resistivity of the Pt x (Si3N4) 1-x alloy thin film changes with the Pt concentration. x (Si3N4) 1-x The resistivity of the alloy thin film decreases with the increase of the Pt concentration, and based on the Pt x (Si3N4) 1-x The change of the resistivity of the alloy thin film and the Pt concentration is approximately linear, which can explain that the resistivity of the Pt x (Si3N4) 1-x alloy thin film prepared in this embodiment can be regulated by changing the Pt concentration, and as shown in the figure, the resistivity of the Pt x (Si3N4) 1-x alloy thin film prepared in this embodiment is low, and the resistivity of the Pt x (Si3N4) 1-x alloy thin film is always within 30-90 μΩcm.

[0082] As Figure 4 shown, the Ptx (Si3N4) 1-x The surface morphology of the alloy thin film was obtained by atomic force microscopy. The arithmetic mean roughness of the material was only 0.12 nanometers, indicating that the material prepared by this embodiment has good flatness, which is beneficial for the fabrication of nanoscale devices.

[0083] like Figure 5 As shown, the Pt prepared in this invention x (Si3N4) 1-x High-resolution transmission electron microscopy images of the alloy thin film reveal the Pt content. x (Si3N4) 1-x The alloy film exhibits a clearly regular polycrystalline structure, indicating that the material prepared in this embodiment has a stable structure and properties.

[0084] Example 2: Ferromagnetic Pt x (Si3N4) 1-x / Co 0.65 Tb 0.35 Device testing

[0085] Figure 6 This is a schematic diagram of the core structure of the magnetic tunnel junction device and the spin Hall oscillator according to an embodiment of the present invention.

[0086] Figure 7 This is a schematic diagram of the track-based in-memory computing device according to an embodiment of the present invention.

[0087] Figure 8 Pt is an embodiment of the present invention. x (Si3N4) 1-x / Co 0.65 Tb 0.35 The relationship between the spin-orbit moment efficiency of the device.

[0088] Figure 9 Pt is an embodiment of the present invention. 0.7 (Si3N4) 0.3 / Co 0.65 Tb 0.35 Current reversal diagram of the device.

[0089] The present invention also provides a low-impedance, high-spin Hall angle device, comprising: Pt x (Si3N4) 1-x Alloy thin films and Co 0.65 Tb 0.35 A magnetic thin film is composited to form a carrier. This carrier is then used in spin-orbit magnetic tunnel junctions, spin Hall oscillators, and track-based in-memory computing devices to obtain Pt. 0.7 (Si3N4) 0.3 / Co 0.65 Tb 0.35Device.

[0090] As Figure 6 shown, the carrier can be applied to various spin-orbit torque driven functional devices and chips, such as Co 0.65 Tb 0.35 In the spin-orbit torque magnetic tunnel junction of the magnetic thin film, Pt x (Si3N4) 1-x The alloy thin film is driven by the spin-orbit torque to flip the direction of the magnetic moment, and the spin-orbit torque is used to realize fast and reliable magnetization flipping, which can effectively improve the writing speed. Or in the spin Hall oscillator, the spin-orbit torque drives the magnetic moment to precess along the dotted line to form an oscillation of a specific frequency. x (Si3N4) 1-x

[0091] As Figure 7 shown, the carrier can also be applied to a racetrack computing device. The same scattering mechanism that produces an anomalous Hall effect in a magnetic field will preferentially scatter electrons carrying spins in a direction perpendicular to the current flow. In one direction, all electrons are spin-up, and in the other direction, all electrons are spin-down. There will be an accumulation effect on the boundaries on both sides, so that the spin-orbit torque drives the Co 0.65 Tb 0.35 Magnetic domain movement of the magnetic thin film.

[0092] As Figure 8 shown, the ferrimagnetic Pt x (Si3N4) 1-x / Co 0.65 Tb 0.35 The spin-orbit torque efficiency of the device monotonically increases with the decrease of the Pt x (Si3N4) 1-x concentration in Pt x (Si3N4) 1-x / Co 0.65 Tb 0.35 The spin-orbit torque of the device can be controlled by changing the Pt concentration.

[0093] As Figure 9 shown, the Pt x (Si3N4) 1-x alloy thin film produces an anomalous Hall effect in a magnetic field by the same scattering mechanism, which preferentially scatters electrons carrying spins in a direction perpendicular to the current flow. In one direction, all electrons are spin-up, and in the other direction, all electrons are spin-down, so that the Pt 0.7 (Si3N4) 0.3 / Co0​0.65 Tb 0.35 At the same current density of the device, the magnetic field direction along the current direction is opposite, Pt x (Si3N4) 1-x The alloy thin film is driven by the spin-orbit torque to reverse the direction of the magnetic moment, and the spin-orbit torque is used to realize fast and reliable magnetization reversal, so that the Pt 0.7 (Si3N4) 0.3 / Co0 0.65 Tb 0.35 The device can be driven by current to realize flip, which shows that the Pt-X alloy thin film and the device have application potential in spin-orbit torque magnetic tunnel junction, spin Hall oscillator, race track storage and computing device.

[0094] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application, and it should be understood that the above description is only a specific embodiment of the present application and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a platinum-based high spin Hall angle material, comprising: adding an impurity to grow a platinum-based metal film, so that the impurity and platinum form an alloy thin film with a polycrystalline or single crystal structure; wherein the impurity is one or more of Si 3N 4, AlN, GaN, SiC; the volume percentage of the impurity is 1%-60%; the platinum in the platinum-based metal film is used to provide a spin Hall effect; the impurity is used to enhance the electron scattering and resistivity of platinum in the platinum-based metal film.

2. The method of claim 1, wherein, The resistivity of the alloy thin film is not more than 120 micro-ohm centimeters.

3. The method of claim 1, wherein, The alloy thin film is grown by a deposition technique based on magnetron sputtering, molecular beam epitaxy, thermal evaporation, ion beam evaporation or laser pulse.

4. The method of claim 3, wherein, The alloy thin film is grown by a deposition technique based on magnetron sputtering, comprising co-sputtering the alloy thin film using one or more targets containing the platinum and / or the impurity components; wherein the argon flow rate for magnetron sputtering is 5-50 sccm; the working gas pressure is 1-8 mTorr. 5.An alloy thin film prepared by the method of any one of claims 1-4. 6.Use of the alloy thin film of claim 5 as a carrier for information generation, processing, storage and transmission in at least one of the following: spin-orbit torque magnetic tunnel junction, spin Hall oscillator, racetrack memory device. 7.The use of claim 6, comprising: compositing the alloy thin film with a magnetic thin film to form the carrier; the carrier generates, processes, stores and transmits information under the action of the spin-orbit torque generated by the alloy thin film.

8. Use according to claim 7, wherein, The magnetic thin film contains one or more of Fe, Co, Ni, Cr, Mn.

9. Use according to claim 7, wherein, The thickness of the magnetic thin film is 0.2-50 nanometers.

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