Gallium nitride two-dimensional electron gas channel side wall spin injection information device structure and preparation method thereof

Abstract

The invention discloses a gallium nitride two-dimensional electron gas channel side wall spin injection information device structure and a preparation method, and belongs to the technical field of semiconductor information devices. The structure comprises a substrate layer, a buffer layer, a channel layer, a barrier layer, a ferromagnetic layer, a C1 electrode layer, a C2 electrode layer, a passivation layer and an electrode window. The preparation method comprises the following steps: preparing a substrate; epitaxial growth; performing etching; growing an electrode; carrying out ferromagnetic growth; growing an electrode; passivating the surface; and windowing and leading wires. According to the gallium nitride two-dimensional electron gas channel side wall spin injection information device structure and the preparation method provided by the invention, ultrahigh-speed information transmission and storage of the device can be realized; an extra ultra-thin insulating layer film is not needed, the ferromagnetic material is in direct contact with the side wall of the heterojunction two-dimensional electron gas channel so as to achieve efficient spin injection, the impedance matching degree with the ferromagnetic material on the side wall is improved through the low resistivity of the two-dimensional electron gas, and meanwhile the process complexity is remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor information devices, and in particular to a gallium nitride two-dimensional electron gas channel sidewall spin injection information device structure and a preparation method thereof. Background Art

[0002] Electrons have three properties: mass, charge and spin, which have been successfully used to form the cornerstone of today's information society. Researchers have successfully developed a large number of electronic information processing products using the charge characteristics of electrons, including integrated circuits, high-frequency and high-power devices, and have developed a series of high-capacity information storage devices such as hard disks, magnetic tapes, and magneto-optical disks using the spin characteristics of electrons. The two have developed independently and achieved remarkable results. However, in recent years, with the further miniaturization of electronic devices and the development of submicron and even nano science and technology, the research progress of semiconductor microelectronics based on charge carriers has been greatly restricted due to factors such as heat dissipation and process size. Moore's Law of semiconductor devices has gradually approached its physical limit. Therefore, the development of new semiconductor devices to break through the limitations of Moore's Law has become an important and extensive topic. Among them, spintronic devices have attracted widespread attention due to their advantages such as low power consumption and high processing speed. Compared with traditional charge devices, electron spin has significant advantages in non-volatility, energy loss, information processing speed, integration density, data storage and data transmission, and can be further freely incorporated into the charge state, simplifying the device structure while enhancing the device performance.

[0003] If the movement of electrons in a three-dimensional solid is blocked and restricted in one direction (such as the z direction), and can only move freely in the other two directions (x and y directions), then this type of electron is called a two-dimensional electron gas. Two-dimensional electron gas is generally easy to obtain in a heterojunction structure. Since the bond lengths formed by atoms in a wurtzite structure semiconductor and its nearest four atoms are different, the negative charge center and the positive charge center formed do not coincide, resulting in a built-in electric field that triggers a spontaneous polarization effect. When two materials with different lattice constants grow together, a lattice mismatch phenomenon will occur, which will in turn cause a piezoelectric polarization effect, generating tensile stress and compressive stress to further shift the charge center, increase the binding of the crystal surface charge, and increase the bound surface charge, thus generating a large amount of interfacial polarization charge. In order to maintain charge balance inside the semiconductor, a considerable concentration of freely movable electrons needs to accumulate near the heterojunction interface to neutralize the interfacial polarization charge. The polarization electric field and the high concentration of electrons will pull down the conduction band at the heterojunction interface to form an electronic potential well. This potential well is extremely stable at room temperature, with the bottom located at E F Therefore, the two-dimensional electron gas has a very high surface density, which can usually reach 1.0×10 13 cm -2The potential well only binds electrons in the direction perpendicular to the two-dimensional electron gas channel, while the degree of electron binding in the horizontal direction can be ignored (it can be regarded as free movement). Therefore, the two-dimensional electron gas has extremely high mobility, electron density and saturation drift velocity when conducting along the channel direction. Information devices made of two-dimensional electron gas have extremely high information propagation rate, which can effectively reduce the probability of information loss during information propagation. Therefore, the combination of two-dimensional electron gas and spin will surely have a broad market.

[0004] Semiconductor spin electronics combines the advantages of existing semiconductor technology and magnetic materials. It mainly studies processes closely related to electron charge and spin. It uses the physical mechanism related to system materials and spin to realize spin injection, spin transport, spin detection and spin control of non-magnetic materials, detect single electron spin, spin coherence and spin relaxation, etc. At the same time, it can also detect magnetic fields by detecting the related states of electron spins, and finally produce new spin electronic devices to integrate different functions such as storage, detection, logic and communication on a single chip. Among them, the understanding of "spin polarized current" provides a high-tech solution to solve the power consumption problem in many current processes. In view of the new round of development boom in basic research and applied research in recent years, semiconductor spin electronics is expected to become an important direction for the development of next-generation information technology, and spin information devices based on two-dimensional electron gas will inevitably be favored by more people due to their advantages such as high electron density and high electron mobility.

[0005] Spin electronics can be basically summarized into three problems: spin injection, spin regulation and spin detection. The latter two can only be achieved on the basis of the first step. Therefore, in the research of spin electronics, spin injection has become the top priority. It is the most basic condition for realizing electronic spin devices. There are many methods for semiconductor spin injection. For example, the light injection method uses circularly polarized light to irradiate the sample. According to the light selection rule of the material, the electrons in the heavy hole band and the light hole band are excited to the conduction band electronic state with different spin orientations, and the ratio of the number of electrons with spin up and spin down changes. Due to the energy level splitting of the heavy hole state and the light hole state, the polarization state and wavelength of the incident light are appropriately selected to generate electrons and holes with different polarizabilities; using the pump injection method, the radio frequency microwave generates ferromagnetic resonance of the FM layer magnetization under a specific DC external magnetic field, and the magnetization precession related to the change of the longitudinal component of the magnetization is transported to the FM / NM interface through dynamic exchange interaction, and a vertical pure spin current is generated in the non-magnetic metal; using the hot electron injection method, a magnetic field with a ratio of E is used. FSpin-polarized electrons with much greater energy. Since majority spin electrons and minority spin electrons have very different inelastic mean free paths, hot electrons passing through the FM layer can be effectively polarized. Using the electrical injection method, electric current passes through ferromagnetic materials to generate spin-polarized current, which is then injected into ordinary semiconductor materials. In addition, there are ballistic electron spin injection methods, etc., among which the electrical injection method is particularly widely used.

[0006] However, when using the electrical injection method for spin injection, the problem of low injection efficiency due to impedance mismatch seriously hinders the further development and utilization of spin electronic devices. Countless researchers have made efforts day and night for this. Some people have proposed that the resistance mismatch problem can be solved by inserting a tunneling layer at the interface to increase the resistance of the contact interface between the ferromagnetic layer and the semiconductor material. Later, in experiments on a large number of materials, it was proved that oxides such as MgO and Al2O3 are an ideal tunneling layer, which can largely solve the resistance mismatch problem. However, this method requires the growth of a thinner tunneling barrier layer, which has high process requirements and greatly increases the process complexity. The quality of the grown film seriously affects the tunneling results and injection efficiency. Among them, in the problem of spin injection of two-dimensional electron gas, some researchers use the barrier layer as an insulating layer to increase the interface impedance while generating two-dimensional electron gas to improve the efficiency of spin injection. Therefore, the thickness of the barrier layer must be guaranteed to be within a few nanometers, and the quality of the two-dimensional electron gas generated by the thinner barrier layer is poor. Therefore, there is a certain contradiction between the two, which affects the final spin injection.

[0007] Therefore, the present invention innovatively proposes a sidewall spin injection structure to complete sidewall spin injection. In this structure, the barrier layer can be grown at the optimal thickness to achieve the preparation of high-quality two-dimensional electron gas, and the traditional electric injection method using an insulating layer barrier is broken. The low resistivity of the two-dimensional electron gas itself is used to improve the impedance matching with the ferromagnetic material. The two-dimensional electron gas channel is in direct contact with the ferromagnetic material to complete the spin injection, without the need for an additional extremely thin insulating layer film, which significantly reduces its process complexity. Summary of the invention

[0008] The purpose of the present invention is to provide a gallium nitride two-dimensional electron gas channel sidewall spin injection information device structure and a preparation method. Different from the traditional spin vertical injection scheme, the invention realizes efficient spin electron injection through the sidewall composite structure, solves the problem that the spin injection rate of the traditional ferromagnetic material is 0 when it is directly in contact with the semiconductor material, and the contradiction between the quality of the two-dimensional electron gas and the injection efficiency in the two-dimensional electron gas spin injection structure.

[0009] To achieve the above-mentioned purpose, the present invention provides a gallium nitride two-dimensional electron gas channel sidewall spin injection information device structure, which is a dual-electrode spin information device. From bottom to top, the structure includes a substrate layer, the top of the substrate layer is connected to a buffer layer, the top of the buffer layer is connected to a channel layer, the top of the channel layer is connected to a barrier layer, one side of the barrier layer and the channel layer is connected to a C1 electrode layer, the other side walls of the barrier layer and the channel layer are connected to a ferromagnetic layer, one side of the ferromagnetic layer is connected to a C2 electrode layer, the top of the barrier layer is connected to a passivation layer, and electrode windows are provided above both the C1 electrode layer and the C2 electrode layer.

[0010] Furthermore, the channel layer is a double "convex"-shaped structure, and after the mesa isolation etching, the device active area presents a first "convex"-shaped structure. Further, before the preparation of the C1 and C2 electrode layers, the two-dimensional electron gas channel is etched on the upper part of the "convex"-shaped structure to form a second "convex" shape, and the ferromagnetic layer and the C2 electrode layer completely cover the side walls of the second "convex"-shaped structure of the two-dimensional electron gas channel.

[0011] It also includes: a gallium nitride two-dimensional electron gas channel sidewall spin injection information device structure, the structure is a dual-electrode spin information device, and the structure from bottom to top includes a substrate layer, the top of the substrate layer is connected to the buffer layer, the top of the buffer layer is connected to the channel layer, the top of the channel layer is connected to the barrier layer, both sides of the barrier layer are connected to electromagnetic layers, one side of one ferromagnetic layer is connected to the C1 electrode layer, one side of the other ferromagnetic layer is connected to the C2 electrode layer, the top of the barrier layer is connected to a passivation layer, and electrode windows are provided above the C1 electrode layer and the C2 electrode layer.

[0012] Furthermore, the channel layer is a double "convex"-shaped structure, and after the mesa isolation etching, the device active area presents a first "convex"-shaped structure. Further, before the preparation of the C1 and C2 electrode layers, the two-dimensional electron gas channel is etched on the upper part of the "convex"-shaped structure to form a second "convex" shape, and the ferromagnetic layer and the C2 electrode layer completely cover the side walls of the second "convex"-shaped structure of the two-dimensional electron gas channel.

[0013] A method for preparing a gallium nitride two-dimensional electron gas channel sidewall spin injection information device comprises the following steps:

[0014] S11, substrate preparation: prepare substrate materials and clean and remove contaminants on the substrate surface;

[0015] S12. Epitaxial growth: epitaxially grow a buffer layer and a heterojunction structure by using any of metal organic chemical vapor deposition, molecular beam epitaxy, and hydride vapor phase epitaxy. The buffer layer is AlN, GaN, or a superlattice structure. The buffer layer has a thickness of 10 nm to 500 nm, the channel layer has a thickness of 0.1 μm to 5 μm, and the barrier layer has a thickness of 1 nm to 100 nm.

[0016] S13, etching: after the epitaxially grown sample is coated, photolithographically and developed, the heterojunction is etched by an inductively coupled plasma etcher, the etching power is 10W to 300W, 50sccm to 300sccm of Cl-based gas is introduced for etching for 150s to 3000s, and the etching depth is 50nm to 1000nm, so as to form the first "convex"-shaped structure of the active area table; then after coating, photolithographically and developed, the active area heterojunction is etched by an inductively coupled plasma etcher, the etching power is 10W to 300W, 50sccm to 300sccm of Cl-based gas is introduced for etching for 150s to 3000s, and the etching depth is 50nm to 500nm, so as to form the second "convex"-shaped structure;

[0017] S14, Ohmic contact electrode growth: by photolithography stripping technology, using electron beam evaporation, thermal evaporation, atomic layer deposition or magnetron sputtering to deposit metal, and annealing to form an ohmic contact. In step S14, the power of the metal preparation is 10W to 300W and the gas pressure is 0.5Pa to 5.0Pa;

[0018] S15, ferromagnetic layer growth: by photolithography stripping technology, using electron beam evaporation, thermal evaporation, atomic layer deposition or magnetron sputtering to prepare a ferromagnetic material film on the side wall, the thickness of the ferromagnetic material film is 5nm to 100nm;

[0019] S16, Ferromagnetic layer electrode growth: Deposit metal by electron beam evaporation, thermal evaporation, atomic layer deposition or magnetron sputtering through photolithography lift-off technology;

[0020] S17, surface passivation: Deposit the passivation layer by atomic layer deposition, plasma enhanced chemical vapor deposition or magnetron sputtering;

[0021] S18, window lead: Corrode the passivation layer in each electrode area to open a window lead.

[0022] Therefore, the present invention adopts a gallium nitride two-dimensional electron gas channel sidewall spin injection information device structure and preparation method of the above structure, which has the following beneficial effects:

[0023] (1) Compared with the existing method of using an extremely thin barrier layer as an insulating layer and sacrificing a certain amount of two-dimensional electron gas quality to complete spin injection, the barrier layer in the scheme proposed by the present invention can be grown at an optimal thickness, so it has better two-dimensional electron gas quality and can directly achieve spin injection of two-dimensional electron gas with better quality.

[0024] (2) The electron mobility of the two-dimensional electron gas is much greater than that of conventional semiconductors, and the electron density is relatively high. Therefore, the conductivity is much greater than that of conventional semiconductors, and the resistivity is much less than that of conventional semiconductors. Therefore, compared with the situation where the spin injection efficiency is 0 in direct contact between the traditional ferromagnetic metal and the semiconductor, the sidewall-type ferromagnetic metal-high-quality two-dimensional electron gas proposed in the present invention has better impedance matching, which is beneficial to improving the spin injection efficiency.

[0025] (3) The channel layer in the present invention is a highly "convex" structure with a large etching depth, which ensures that all the two-dimensional electron gas on the entire side of the interface is in full contact with the ferromagnetic material, resulting in a larger contact area and higher injection efficiency.

[0026] (4) In the solution proposed by the present invention, the ferromagnetic material is innovatively grown on the side wall to complete the side wall spin injection, and the electrons are directly injected laterally through the right electrode and transported, avoiding the loss of traditional longitudinal injection and achieving higher injection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a front view of a gallium nitride two-dimensional electron gas channel sidewall spin injection information device structure of the present invention;

[0028] Figure 2 A top view of a gallium nitride two-dimensional electron gas channel sidewall spin injection information device structure of the present invention;

[0029] Figure 3 This is a structural flow chart of a gallium nitride two-dimensional electron gas channel sidewall spin injection information device in Example 1 of the present invention;

[0030] Figure 4 This is a front view of the structure of a gallium nitride two-dimensional electron gas channel sidewall spin injection information device in Example 1 of the present invention;

[0031] Figure 5 This is a structural flow chart of a gallium nitride two-dimensional electron gas channel sidewall spin injection information device in Example 2 of the present invention;

[0032] Figure 6 A front view of the structure of a gallium nitride two-dimensional electron gas channel sidewall spin injection information device in Example 2 of the present invention

[0033] Figure 7 A barrier height comparison diagram of a gallium nitride two-dimensional electron gas channel sidewall spin injection information device structure and a preparation method of the present invention with and without an AlN layer structure;

[0034] Figure 8A graph showing the relationship between doping concentration and spin injection rate of a gallium nitride two-dimensional electron gas channel sidewall spin injection information device structure and a preparation method thereof according to the present invention;

[0035] Fig. 9 A graph showing the relationship between electron mobility and spin injection rate of a gallium nitride two-dimensional electron gas channel sidewall spin injection information device structure and a preparation method thereof according to the present invention;

[0036] Reference numerals

[0037] 1. Substrate layer, 2. Buffer layer, 3. Channel layer, 4. Barrier layer, 5. Ferromagnetic layer, 6. C1 electrode layer, 7. C2 electrode layer, 8. Passivation layer, 9. Electrode window. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0039] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0040] Example 1

[0041] like Figure 1-Figure 2 As shown, the present invention provides a gallium nitride two-dimensional electron gas channel sidewall spin injection information device structure, the structure is a dual-electrode spin information device, and the structure from bottom to top includes a substrate layer 1, the upper part of the substrate layer 1 is connected to the buffer layer 2, the upper part of the buffer layer 2 is connected to the channel layer 3, the upper part of the channel layer 3 is connected to the barrier layer 4, one side of the barrier layer 4 and the channel layer is connected to a C1 electrode layer 6, the other side wall of the barrier layer 4 and the channel layer is connected to a ferromagnetic layer 5, one side of the ferromagnetic layer 5 is connected to a C2 electrode layer 7, the upper part of the barrier layer 4 is connected to a passivation layer 8, and electrode windows 9 are provided above the C1 electrode layer 6 and the C2 electrode layer 7.

[0042] like Figure 3-Figure 4 As shown, a method for preparing a gallium nitride two-dimensional electron gas channel sidewall spin injection information device comprises the following steps:

[0043] S11. Substrate preparation: prepare a 2-inch Si substrate material, perform ultrasonic cleaning in acetone (MOS grade) for 2 minutes, boil in 60°C positive photoresist stripping solution for 10 minutes, perform ultrasonic cleaning on the sample in acetone and ethanol for 3 minutes each, clean with HF:H2O=1:5 hydrofluoric acid solution for 30s, rinse with deionized water and blow dry with pure N2.

[0044] S12. Epitaxial growth: epitaxially grow buffer layer AlN and AlGaN / GaN heterojunction structure by metal organic chemical vapor deposition, wherein the thickness of the channel layer is 4 μm, the thickness of the barrier layer is 25 nm, the Al component in the barrier layer is 0.25, and the thickness of the AlN buffer layer is 15 nm.

[0045] S13, etching: after the epitaxially grown samples are coated with glue (using AZ6130 positive photoresist), spread (forward rotation 600rpm-3s, rear rotation 1000rmp-20s, the final photoresist thickness is 2um), photolithography, and development (90s), the heterojunction is etched by an inductively coupled plasma etcher, with an etching power of 200W, 150sccm of Cl-based gas is introduced for etching for 250s, and the etching depth is 100nm, forming the active area table of the first "convex" type structure; then after coating, photolithography, and development, the active area heterojunction is etched by an inductively coupled plasma etcher, with an etching power of 10W~300W, 50sccm~300sccm of Cl-based gas is introduced for etching for 150s~3000s, and the etching depth is 50nm~500nm, forming the second "convex" type structure.

[0046] S14, Ohmic contact electrode growth: After coating (using AZ6130 positive photoresist), spreading (forward rotation 600rpm-3s, rear rotation 1000rmp-20s, the final photoresist thickness is 2um), photolithography, and development (90s), 250nm Ti / Al / W metal is deposited by magnetron sputtering, and annealed at 550℃ for 70s under vacuum conditions to form an ohmic contact, thereby forming an electrode C1.

[0047] S15, ferromagnetic layer growth: after coating (using AZ6130 positive photoresist), spreading (forward rotation 600rpm-3s, rear rotation 1000rmp-20s, the final photoresist thickness is 2um), photolithography, and development (90s), a ferromagnetic material film with a side wall thickness of 20nm was prepared by magnetron sputtering. The sputtering power was 110W, the sputtering pressure was 1.5Pa, the target spacing was 80mm, and the background vacuum was 2×10 - 5 Pa.

[0048] S16, ferromagnetic layer electrode growth: after coating (using AZ6130 positive photoresist), leveling (forward rotation 600rpm-3s, rear rotation 1000rmp-20s, the final photoresist thickness is 2um), photolithography, and development (90s), the magnetron sputtering method is used to prepare Au with a thickness of 100nm as the electrode C2.

[0049] S17, surface passivation: plasma enhanced chemical vapor deposition is used to deposit a 300nm thick Si3N4 passivation layer at 300℃ to weaken the influence of the ambient atmosphere on the device characteristics.

[0050] S18, opening window leads: utilizing photolithography and development technology, using hydrofluoric acid solution to corrode the passivation layer of the electrode regions C1 and C2, thereby opening window leads.

[0051] Example 2

[0052] like Figure 5-Figure 6 As shown, the present invention provides a gallium nitride two-dimensional electron gas channel sidewall spin injection information device structure, which is a dual-electrode spin information device. From bottom to top, the structure includes a substrate layer 1, the upper part of the substrate layer 1 is connected to the buffer layer 2, the upper part of the buffer layer 2 is connected to the channel layer 3, the upper part of the channel layer 3 is connected to the barrier layer 4, and both sides of the barrier layer 4 are connected to electromagnetic layers 5, one side of one ferromagnetic layer 5 is connected to the C1 electrode layer 6, and one side of the other ferromagnetic layer 5 is connected to the C2 electrode layer 7, the upper part of the barrier layer 4 is connected to the passivation layer 8, and the upper parts of the C1 electrode layer 6 and the C2 electrode layer 7 are provided with electrode windows 9.

[0053] A method for preparing a gallium nitride two-dimensional electron gas channel sidewall spin injection information device comprises the following steps:

[0054] S21. Substrate preparation: prepare a 2-inch Si substrate material, perform ultrasonic cleaning in acetone (MOS grade) for 2 minutes, boil in 60°C positive resist stripping solution for 10 minutes, perform ultrasonic cleaning on the sample in acetone and ethanol for 3 minutes each, clean with HF:H2O=1:5 hydrofluoric acid solution for 30 seconds, rinse with deionized water and blow dry with pure N2.

[0055] S22. Epitaxial growth: epitaxially grow a buffer layer AlN and an AlGaN / GaN heterojunction structure by metal organic chemical vapor deposition, wherein the thickness of the channel layer is 4 μm, the thickness of the barrier layer is 25 nm, the Al component in the barrier layer is 0.25, and the thickness of the AlN buffer layer is 15 nm.

[0056] S23, etching: after the epitaxially grown samples are coated with glue (using AZ6130 positive photoresist), spread (forward rotation 600rpm-3s, rear rotation 1000rmp-20s, the final photoresist thickness is 2um), photolithography, and development (90s), the heterojunction is etched by an inductively coupled plasma etcher, with an etching power of 200W, 150sccm of Cl-based gas is introduced for etching for 250s, and the etching depth is 100nm, forming the active area table of the first "convex" type structure; then after coating, photolithography, and development, the active area heterojunction is etched by an inductively coupled plasma etcher, with an etching power of 10W~300W, 50sccm~300sccm of Cl-based gas is introduced for etching for 150s~3000s, and the etching depth is 50nm~500nm, forming the second "convex" type structure.

[0057] S24, Ferromagnetic layer growth: A ferromagnetic material film is grown on the sample by magnetron sputtering. The sputtering power is 110W, the sputtering pressure is 1.5Pa, the target spacing is 80mm, and the background vacuum is 2×10 -5 Pa.

[0058] S25. Ferromagnetic layer treatment: Bombard the sample surface with plasma to remove the surface ferromagnetic material and complete the preparation of the sidewall film.

[0059] S26. Ferromagnetic layer electrode growth: After coating (using AZ6130 positive photoresist), leveling (forward rotation 600rpm-3s, rear rotation 1000rmp-20s, the final photoresist thickness is 2um), photolithography, and development (90s), magnetron sputtering is used to prepare Au with a thickness of 100nm as electrodes C1 and C2.

[0060] S27, surface passivation: plasma enhanced chemical vapor deposition is used to deposit a 300nm thick Si3N4 passivation layer at 300℃ to weaken the influence of the ambient atmosphere on the device characteristics.

[0061] S28. Opening window leads: utilizing photolithography and development technology, using hydrofluoric acid solution to corrode the passivation layer of the electrode regions C1 and C2, thereby opening window leads.

[0062] Figure 7 The comparison of barrier heights with and without AlN layer structures is given. Previous studies have shown that spin-polarized electrons passing through the ferromagnetic layer can enter the two-dimensional electron gas through a thinner AlN layer for spin transport. Figure 7 The solid black line indicates that the two-dimensional electron gas first contacts the 3nm AlN and then contacts the electrode. The dashed line indicates that the two-dimensional electron gas directly contacts the electrode. The dotted line indicates the Fermi level. Figure 7It can be clearly seen that the thickness of the barrier without the addition of AlN material is significantly smaller than that with the addition of AlN material. Therefore, if electrons can enter the two-dimensional electron gas through the AlN layer barrier, they can certainly enter the two-dimensional electron gas through the thin barrier without the addition of AlN layer.

[0063] Figure 8 The variation of spin injection rate with doping concentration is given. Increasing the doping concentration and thus increasing the electron concentration can simulate the increase of electron concentration in the two-dimensional electron gas. Figure 8 It can be seen that as the doping concentration increases, the electron concentration gradually increases, and the spin injection rate also gradually increases, and can even reach more than ten percent. Fig. 9 The variation of spin injection rate with electron mobility is given by Fig. 9 It can be seen that increasing the electron mobility can increase the spin injection rate. Figure 8-Figure 9 In summary, the greater the electron concentration, the higher the electron mobility and the greater the spin injection rate, that is, the better the quality of the prepared two-dimensional electron gas and the higher the spin injection rate.

[0064] It can be seen that the barrier layer can be grown at the optimal thickness to achieve the preparation of high-quality two-dimensional electron gas, and break the traditional electrical injection method using an insulating layer barrier. The low resistivity of the two-dimensional electron gas itself is used to improve the impedance matching with the ferromagnetic material. The two-dimensional electron gas channel is in direct contact with the ferromagnetic material to complete the spin injection. No additional extremely thin insulating layer film is required, which significantly reduces the process complexity. In addition, the growth of sidewall ferromagnetic material is innovatively proposed to complete the sidewall spin injection.

[0065] In the gallium nitride two-dimensional electron gas channel sidewall spin injection information device structure and preparation method thereof described in the present invention, the high mobility of the two-dimensional electron gas can enable the device to achieve ultra-high-speed transmission and ultra-fast response, thereby improving the transmission and storage efficiency of information; spin injection of the two-dimensional electron gas can simultaneously control the charge properties and spin properties of the electrons, thereby increasing the freedom of information processing, reducing power consumption, and increasing integration, and has broad application prospects.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A gallium nitride two-dimensional electron gas channel sidewall spin injection information device structure, characterized in that: The structure is a dual-electrode spin information device, which includes a substrate layer from bottom to top. The upper part of the substrate layer is connected to the buffer layer, the upper part of the buffer layer is connected to the channel layer, the upper part of the channel layer is connected to the barrier layer, one side of the barrier layer and the channel layer is connected to a C1 electrode layer, the other side walls of the barrier layer and the channel layer are connected to a ferromagnetic layer, one side of the ferromagnetic layer is connected to a C2 electrode layer, the upper part of the barrier layer is connected to a passivation layer, and electrode windows are provided above the C1 electrode layer and the C2 electrode layer.

2. A gallium nitride two-dimensional electron gas channel sidewall spin injection information device structure, characterized in that: The structure is a dual-electrode spin information device, which includes a substrate layer from bottom to top. The top of the substrate layer is connected to the buffer layer, the top of the buffer layer is connected to the channel layer, the top of the channel layer is connected to the barrier layer, both sides of the barrier layer are connected to electromagnetic layers, one side of one ferromagnetic layer is connected to the C1 electrode layer, one side of the other ferromagnetic layer is connected to the C2 electrode layer, the top of the barrier layer is connected to a passivation layer, and electrode windows are provided above the C1 electrode layer and the C2 electrode layer.

3. A gallium nitride two-dimensional electron gas channel sidewall spin injection information device structure according to claim 1 or 2, characterized in that: The channel layer is a double "convex"-shaped structure. After the mesa isolation etching, the device active area presents a first "convex"-shaped structure. Further, before the C1 and C2 electrode layers are prepared, the two-dimensional electron gas channel is etched on the upper part of the "convex"-shaped structure to form a second "convex" shape. The ferromagnetic layer and the C2 electrode layer completely cover the side walls of the two-dimensional electron gas channel of the second "convex"-shaped structure.

4. A method for preparing a gallium nitride two-dimensional electron gas channel sidewall spin injection information device, characterized in that: The following steps are involved: S11, substrate preparation: prepare substrate materials and clean and remove contaminants on the substrate surface; S12. Epitaxial growth: epitaxially grow a buffer layer and a heterojunction structure by using any of metal organic chemical vapor deposition, molecular beam epitaxy, and hydride vapor phase epitaxy. The buffer layer is AlN, GaN, or a superlattice structure. The buffer layer has a thickness of 10 nm to 500 nm, the channel layer has a thickness of 0.1 μm to 5 μm, and the barrier layer has a thickness of 1 nm to 100 nm. S13, etching: after the epitaxially grown sample is coated, photolithographically and developed, the heterojunction is etched by an inductively coupled plasma etcher, with an etching power of 10W to 300W, 50sccm to 300sccm of Cl-based gas is introduced for etching for 150s to 3000s, and the etching depth is 50nm to 1000nm, so as to form the first "convex"-shaped structure of the active area table; then after coating, photolithographically and developed, the active area heterojunction is etched by an inductively coupled plasma etcher, with an etching power of 10W to 300W, 50sccm to 300sccm of Cl-based gas is introduced for etching for 150s to 3000s, and the etching depth is 50nm to 500nm, so as to form the second "convex"-shaped structure; S14, Ohmic contact electrode growth: by photolithography stripping technology, using electron beam evaporation, thermal evaporation, atomic layer deposition or magnetron sputtering to deposit metal, and annealing to form an ohmic contact. In step S14, the power of the metal preparation is 10W to 300W and the gas pressure is 0.5Pa to 5.0Pa; S15, ferromagnetic layer growth: by photolithography stripping technology, using electron beam evaporation, thermal evaporation, atomic layer deposition or magnetron sputtering to prepare a ferromagnetic material film on the side wall, the thickness of the ferromagnetic material film is 5nm to 100nm; S16, Ferromagnetic layer electrode growth: Deposit metal by electron beam evaporation, thermal evaporation, atomic layer deposition or magnetron sputtering through photolithography lift-off technology; S17, surface passivation: Deposit the passivation layer by atomic layer deposition, plasma enhanced chemical vapor deposition or magnetron sputtering; S18, window lead: Corrode the passivation layer in each electrode area to open a window lead.

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