A method for preparing a gallium nitride single crystal wafer

Abstract

The present application relates to the technical fields of semiconductor material preparation, and particularly relates to a preparation method of gallium nitride single wafer material, which comprises the following steps: placing a silicon carbide substrate sheet larger than a standard size in a containing groove of a graphite tray and assembling a cylindrical silicon nitride ceramic protective cover into the substrate tray to form a substrate tray; placing the substrate tray into a magnetron sputtering growth chamber to sequentially prepare a zinc-aluminum-oxygen polycrystalline thin film and an aluminum nitride polycrystalline thin film; placing the substrate tray into a high-temperature high-vacuum annealing furnace chamber to perform high-temperature high-vacuum annealing treatment; placing the substrate tray into a hydride vapor phase epitaxy reaction chamber to prepare a gallium nitride single thick film material; performing cutting, grinding and polishing processing on the peeled-off gallium nitride single thick film wafer larger than the standard size to obtain a standard-size gallium nitride single wafer material; and cleaning the peeled-off silicon carbide substrate sheet and the used cylindrical silicon nitride ceramic protective cover for reuse. The present application can realize low-stress, low-dislocation density, low-cost and high-yield preparation of the standard-size gallium nitride single wafer material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor material preparation, and particularly relates to a gallium nitride single wafer preparation method. BACKGROUND

[0002] The gallium nitride single crystal material is epitaxially grown on a hetero-substrate wafer by using a hydride vapor phase epitaxy process. In the prior art, a graphite tray plated with a silicon carbide protective coating is used as a substrate tray. First, the substrate wafer is placed into a containing groove on the top of the graphite tray, and then the graphite tray loaded with the substrate wafer is installed on a rotating base in a reaction chamber of a hydride vapor phase epitaxy device. After the gallium nitride single crystal thick film is rapidly prepared by using the hydride vapor phase epitaxy process, the graphite tray is taken out after cooling, and the gallium nitride single crystal thick film material is peeled off from the substrate wafer. Since the gap between the substrate wafer and the containing groove of the graphite tray is filled with gallium nitride material, it is not convenient to clean the graphite tray, and it is also not convenient to take out the prepared gallium nitride single crystal thick film material. If the gap between the substrate wafer and the containing groove of the graphite tray is completely blocked, a part of the substrate wafer will be inevitably blocked. The diameter of the gallium nitride single crystal thick film prepared by using a standard-size substrate wafer is smaller than the standard size. After the self-supporting gallium nitride single crystal thick film wafer is cut, ground and polished, the outer diameter of the gallium nitride single wafer material will also be smaller than the standard size. If the gallium nitride single wafer is used as a homo-substrate to develop and produce gallium nitride-based devices, the subsequent gallium nitride device manufacturing process will be affected, the number of gallium nitride devices produced will be reduced, and the device production cost will be high and the yield will be low. SUMMARY

[0003] The present application provides a gallium nitride single wafer preparation method to solve the problem that the outer diameter of the gallium nitride single wafer material prepared by using a standard-size substrate wafer is smaller than the standard size due to the need to block the gap between the substrate wafer and the containing groove of the graphite tray, and the device production cost is high and the yield is low if the gallium nitride single wafer is used to manufacture devices.

[0004] The present application provides a gallium nitride single wafer preparation method, which comprises the following steps:

[0005] S1: placing a silicon carbide substrate wafer larger than a standard size in a containing groove of a graphite tray, installing a cylindrical silicon nitride ceramic protective cover on the graphite tray, and assembling a substrate tray;

[0006] S2: installing the substrate tray in S1 upside down on a rotating base in a growth chamber of a magnetron sputtering device, and preparing a zinc-aluminum oxide polycrystalline thin film and an aluminum nitride polycrystalline thin film on the silicon carbide substrate wafer larger than the standard size in sequence;

[0007] S3: After the substrate tray in S2 is taken out and cooled, it is placed in a high-temperature high-vacuum annealing furnace chamber to perform high-temperature high-vacuum annealing treatment, so that the zinc-aluminum oxide polycrystalline thin film is converted into a porous aluminum oxide weakly-bonded decoupling layer, and the aluminum nitride polycrystalline thin film is converted into an aluminum nitride single-crystal template layer;

[0008] S4: After the substrate tray in S3 is taken out and cooled, it is inverted and mounted on a substrate rotating base in a hydride vapor phase epitaxy device reaction chamber, and a hydride vapor phase epitaxy process is used to deposit a gallium nitride single-crystal thick film on the aluminum nitride single-crystal template layer.

[0009] S5: The substrate tray in S4 is taken out and cooled, the cylindrical silicon nitride ceramic protective cover is removed, and a greater-than-standard-size gallium nitride single-crystal thick film wafer is peeled off from the greater-than-standard-size silicon carbide substrate sheet.

[0010] S6: The greater-than-standard-size silicon nitride single-crystal thick film wafer is cut, ground and polished to obtain a standard-size gallium nitride single-crystal wafer material.

[0011] S7: The greater-than-standard-size silicon carbide substrate sheet and the silicon nitride ceramic protective cover are subjected to high-temperature high-vacuum baking and cleaning in a chlorine atmosphere.

[0012] S8: Steps S1 to S7 are repeated.

[0013] In some embodiments, in step S1, a deposition window is formed in the cylindrical silicon nitride ceramic protective cover, and the cylindrical silicon nitride ceramic protective cover is flexibly connected to the graphite tray.

[0014] In some embodiments, in step S2, when the zinc-aluminum oxide polycrystalline thin film is prepared, argon is used as the sputtering gas, oxygen is used as the reaction gas, and a zinc-aluminum oxide polycrystalline thin film with a thickness of 10-50 nm and an aluminum content of 20-80% is prepared by using a metal zinc target and a metal aluminum target to perform reactive co-sputtering.

[0015] In some embodiments, in step S2, when the aluminum nitride polycrystalline thin film is prepared, argon is used as the sputtering gas, nitrogen is used as the reaction gas, and an aluminum nitride polycrystalline thin film with a thickness of 100-1000 nm is prepared by using a metal aluminum target to perform reactive sputtering.

[0016] In some embodiments, in step S3, the high-temperature high-vacuum annealing treatment is performed by heating to 1400-1600℃ in a hydrogen atmosphere and maintaining for 5-10 hours in a vacuum state.

[0017] In some embodiments, in step S3, the dislocation density of the aluminum nitride single-crystal template layer is less than 5×10 7 cm -2 .

[0018] In some embodiments, the thickness of the gallium nitride single crystal thick film in step S4 is 300-2000µm.

[0019] In some embodiments, the dislocation density of the standard size gallium nitride single crystal wafer in step S6 is less than or equal to 1×10 6 cm -2 .

[0020] In some embodiments, the size of the standard size silicon carbide substrate wafer in step S1 includes but is not limited to 2, 4, 6, 8, 12 inches.

[0021] In some embodiments, the size of the standard size gallium nitride single crystal wafer material includes but is not limited to 2, 4, 6, 8, 12 inches.

[0022] The beneficial effects of the present application are as follows: the gallium nitride single crystal wafer preparation method provided by the present application uses a silicon carbide substrate wafer larger than the standard size, a cylindrical silicon nitride ceramic protective cover, and introduces a suitable weakly bonded decoupling layer, which can prepare a standard size gallium nitride single crystal wafer, facilitate subsequent homoepitaxial preparation of gallium nitride devices on the gallium nitride single crystal wafer, and realize the reuse of non-standard size silicon carbide substrate wafers, thereby reducing the preparation cost of standard size gallium nitride single crystal wafer materials and improving the yield of gallium nitride single crystal wafers. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a flowchart of a gallium nitride single crystal wafer preparation method of the present application;

[0024] Figure 2 is a structural schematic diagram of a graphite tray installed with a cylindrical silicon nitride ceramic protective cover;

[0025] Figure 3 is Figure 2 a structural schematic diagram of a flexible connecting piece.

[0026] In the drawings, 1 is a graphite tray; 11 is a containing groove; 12 is a positioning hole; 13 is a graphite base; 2 is a cylindrical silicon nitride ceramic protective cover; 21 is a deposition window; 22 is a mounting hole; 3 is a substrate wafer; 4 is a gallium nitride single crystal thick film; 5 is a flexible connecting piece; 51 is a positioning bolt; 52 is a fastening bolt; 53 is a ceramic spring; 6 is a porous alumina weakly bonded decoupling layer; 7 is an aluminum nitride single crystal template layer; 8 is a rotating base; 9 is a screw rod. DETAILED DESCRIPTION

[0027] The technical solutions of the present application will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0028] In the embodiments of the present application, various high-purity substances are used. The purity of zinc in the high-purity zinc metal target is greater than 99.99%; the purity of aluminum in the high-purity aluminum metal target is greater than 99.99%; the purity of gallium in the high-purity gallium metal is greater than 99.99%; the purity of nitrogen in the high-purity nitrogen gas is greater than 99.9999%; the purity of argon in the high-purity argon gas is greater than 99.999%; the purity of hydrogen in the high-purity hydrogen gas is greater than 99.9999%; and the purity of hydrogen chloride in the high-purity hydrogen chloride gas is greater than 99.9999%.

[0029] As described in the background, after the gap between the shielding substrate sheet and the graphite tray containing groove is shielded, the outer diameter of the gallium nitride single crystal thick film prepared by using the standard size substrate is less than the standard size, and then the device is manufactured by using the same, resulting in the problems of high production cost and low yield. Therefore, how to prepare a standard size gallium nitride single crystal thick film, reduce the production cost and improve the yield has become a technical problem to be solved by those skilled in the art.

[0030] To solve the above problems, with reference to Figure 1 , Figure 2 and Figure 3 , the present application provides a gallium nitride single crystal sheet preparation method, comprising the following steps:

[0031] S1: placing a silicon carbide substrate sheet 3 larger than the standard size in the containing groove 11 of the graphite tray 1, installing a cylindrical silicon nitride ceramic protective cover 2 on the graphite tray 1, and assembling to obtain a substrate tray;

[0032] S2: installing the substrate tray in S1 upside down on the rotating base 8 of the growth chamber of the magnetron sputtering equipment, and preparing a zinc-aluminum oxide polycrystalline thin film and an aluminum nitride polycrystalline thin film on the silicon carbide substrate sheet 3 larger than the standard size in sequence;

[0033] S3: after cooling the substrate tray in S2, taking it out and placing it into a high-temperature high-vacuum annealing furnace chamber, and performing high-temperature high-vacuum annealing treatment, the zinc-aluminum oxide polycrystalline thin film is converted into a porous aluminum oxide weakly bonded decoupling layer 6, and the aluminum nitride polycrystalline thin film is converted into an aluminum nitride single crystal template layer 7;

[0034] S4: after cooling and taking out the substrate tray in S3, installing it upside down on the substrate rotating base 8 in the reaction chamber of the hydride vapor phase epitaxy equipment, and depositing a gallium nitride single crystal thick film 4 on the aluminum nitride single crystal template layer 7 by using a hydride vapor phase epitaxy process;

[0035] S5: After the substrate tray in S4 is cooled and taken out, the cylindrical silicon nitride ceramic protective cover 2 is removed, the gallium nitride single crystal thick film 4 is peeled off from the silicon carbide substrate sheet 3, and a gallium nitride single crystal thick film wafer 4 larger than a standard size is obtained;

[0036] S6: The gallium nitride single crystal thick film wafer 4 larger than the standard size is cut, ground, and polished to obtain a gallium nitride single crystal sheet material of a standard size;

[0037] S7: The silicon carbide substrate sheet 3 larger than the standard size and the cylindrical silicon nitride ceramic protective cover 2 are subjected to high-temperature high-vacuum baking and cleaning in a chlorine gas atmosphere;

[0038] S8: Steps S1 to S7 are repeated.

[0039] The present application uses a silicon carbide substrate sheet 3 larger than a standard size to grow a gallium nitride single crystal thick film 4 larger than a standard size on a substrate tray with a cylindrical silicon nitride ceramic protective cover 2, and a gallium nitride single crystal sheet material of a standard size is obtained through cutting, grinding, and polishing, so that gallium nitride devices can be prepared on the gallium nitride single crystal sheet material through homoepitaxy, thereby reducing production cost and improving yield.

[0040] Preferably, in step S1, a deposition window 21 is formed on the cylindrical silicon nitride ceramic protective cover 2, and the outer side wall of the cylindrical silicon nitride ceramic protective cover 2 is flexibly connected to the graphite tray 1. For example, the silicon carbide substrate sheet 3 is placed in the accommodating groove 11 of the graphite tray 1, the outer diameter of the silicon carbide substrate sheet 3 is 3-6 mm larger than the outer diameter of the standard-size silicon carbide substrate sheet 3, the inner diameter of the accommodating groove 11 is 1-2 mm larger than the outer diameter of the non-standard-size silicon carbide substrate sheet 3, the inner diameter of the deposition window 21 is 2-3 mm smaller than the outer diameter of the non-standard-size silicon carbide substrate sheet 3, the cylindrical silicon nitride ceramic protective cover 2 is installed on the graphite tray 1 with the non-standard-size silicon carbide substrate sheet 3, and the graphite tray 1 is connected to the cylindrical silicon nitride ceramic protective cover 2 by using a flexible connecting piece 5 to achieve non-rigid connection.

[0041] Preferably, in step S2, the substrate tray is invertedly installed on the substrate rotating base 8 in the growth chamber of the magnetron sputtering device, the connection and fixation of the rotating base 8 and the graphite tray 1 can be achieved by the screw rod 9, specifically by connecting the rotating base 8 with the graphite base 13. For example, first, the sputtering gas argon and the reaction gas oxygen are introduced into the growth chamber of the magnetron sputtering device, and the super-thin zinc-aluminum oxide polycrystalline thin film is prepared by using the metal zinc target and the metal aluminum target reaction co-sputtering process, the thickness of the zinc-aluminum oxide polycrystalline thin film is 10-50 nm, and the aluminum component content is 20-80%, after the preparation of the zinc-aluminum oxide polycrystalline thin film, the magnetron sputtering is stopped, and the introduction of the sputtering gas argon and the reaction gas oxygen is also stopped; then, the sputtering gas argon and the reaction gas nitrogen are introduced into the growth chamber of the magnetron sputtering device, and the aluminum nitride polycrystalline thin film is prepared by using the metal aluminum target reaction sputtering process, the thickness of the aluminum nitride polycrystalline thin film is 100-1000 nm, after the preparation of the aluminum nitride polycrystalline thin film, the magnetron sputtering is stopped, and the introduction of the sputtering gas argon and the reaction gas nitrogen is also stopped.

[0042] Preferably, in step S3, the substrate tray after cooling is taken out from the growth chamber of the magnetron sputtering device, and then is placed into the high-temperature high-vacuum annealing furnace chamber, the hydrogen gas is introduced to slowly heat to 1400-1600℃, and the high-temperature high-vacuum annealing treatment is carried out for 5-10 hours, the zinc component in the super-thin zinc-aluminum oxide polycrystalline thin film is decomposed and analyzed to form the super-thin porous alumina weakly-bonded decoupling layer 6, and the thin aluminum nitride polycrystalline thin film is recrystallized to form the thin aluminum nitride single-crystal thin film template layer 7 with a dislocation density not higher than 5×10 7 cm -2 thin aluminum nitride single-crystal thin film template layer 7.

[0043] Preferably, in step S4, the substrate tray after cooling is taken out from the high-temperature high-vacuum annealing furnace chamber, the cylindrical silicon nitride ceramic protective cover 2 is first taken off, and then another cylindrical silicon nitride ceramic protective cover 2 is installed, the substrate tray is invertedly installed on the substrate rotating base 8 in the hydride vapor phase epitaxy device reaction chamber, and the gallium nitride single-crystal thick film 4 with a thickness of 300-2000µm is prepared by using the hydride vapor phase epitaxy process.

[0044] Preferably, in step S5, the substrate tray after cooling in the hydride vapor phase epitaxy reaction chamber is taken out, the cylindrical silicon nitride ceramic protective cover 2 is first taken off, the non-standard size silicon carbide substrate sheet 3 with the prepared gallium nitride single-crystal thick film 4 is taken out from the containing groove 11 of the graphite tray 1, and the gallium nitride single-crystal thick film 4 is peeled off from the super-thin porous alumina weakly-bonded decoupling layer 6 to obtain the complete self-supporting non-standard size gallium nitride single-crystal thick film 4.

[0045] Preferably, in step S6, the self-supporting non-standard size gallium nitride single crystal thick film 4 is cut, ground and polished to remove the excess edge, part of the high dislocation density gallium nitride single crystal thick film 4 containing the residual aluminum oxide weakly bonded decoupling layer 6 and the aluminum nitride single crystal thin film template layer 7, to obtain a standard size gallium nitride single crystal wafer material without warping, low stress and low dislocation density. The dislocation density of the standard size gallium nitride single crystal wafer material is less than or equal to 1×10 6 cm -2 .

[0046] Preferably, in step S7, the non-standard size silicon carbide substrate wafer 3 peeled off is subjected to high temperature and high vacuum baking and cleaning in a chlorine atmosphere to completely remove the residual aluminum oxide weakly bonded decoupling layer 6 on the surface, and the cylindrical silicon nitride ceramic protective cover 2 is subjected to high temperature and high vacuum baking in a chlorine atmosphere to completely remove the deposited gallium nitride material in part of the surface area.

[0047] Preferably, in step S8, steps S1 to S7 are repeated to realize the repeated use of the non-standard size silicon carbide substrate wafer.

[0048] Preferably, in step S1, the size of the standard size silicon carbide substrate wafer 3 includes but is not limited to 2, 4, 6, 8, 12 inches, and the size of the standard size gallium nitride single crystal wafer includes but is not limited to 2, 4, 6, 8, 12 inches.

[0049] It should be noted that the specific scheme for shielding the gap between the substrate wafer 3 and the graphite tray groove 11 can be to set a cylindrical silicon nitride ceramic protective cover 2 on the graphite tray 1, such as Figure 2 and Figure 3As shown, the top of the graphite tray 1 is provided with a containing groove 11 for placing the substrate sheet 3, and the size of the containing groove 11 is greater than that of the substrate sheet 3. The cylindrical silicon nitride ceramic protective cover 2 is sleeved on the graphite tray 1, the top of the cylindrical silicon nitride ceramic protective cover 2 is provided with a deposition window 21, the deposition window 21 is coaxially arranged with the containing groove 11, that is, the center of the deposition window 21 and the containing groove 11 is in the same position in the vertical direction, and the inner diameter of the deposition window 21 is less than or equal to the outer diameter of the substrate sheet 3. The height of the substrate sheet 3 is less than or equal to the depth of the containing groove 11. The depth of the deposition window 21 is greater than or equal to the thickness of the gallium nitride single crystal thick film 4. The flexible connecting piece 5 is used to connect the graphite tray 1 and the cylindrical silicon nitride ceramic protective cover 2, thereby realizing non-rigid connection. The flexible connecting piece 5 comprises a positioning bolt 51, a fastening bolt 52 and a ceramic spring 53, one end of the ceramic spring 53 is connected with the positioning bolt 51, and the other end of the ceramic spring 53 is connected with the fastening bolt 52. The positioning bolt 51 and the fastening bolt 52 are made of silicon nitride ceramic material, and the ceramic spring 53 is made of high-temperature-resistant and corrosion-resistant ceramic material. The outer periphery of the graphite tray 1 is provided with a positioning hole 12, and the positioning hole 12 is detachably connected with the positioning bolt 51. The circumferential direction of the silicon nitride ceramic protective cover 2 is provided with a mounting hole 22, and the mounting hole 22 is detachably connected with the fastening bolt 52. The substrate tray can be installed upside down on the substrate rotating base of the hydride vapor phase epitaxy device.

[0050] Compared with the prior art, the present application has the following beneficial effects:

[0051] 1. Compared with the gallium nitride single crystal thick film prepared by using a standard size silicon carbide substrate sheet and also using a cylindrical silicon nitride ceramic protective cover, in order to avoid the deposition of gallium nitride material in the gap between the substrate sheet and the groove of the graphite tray, and to improve the yield of the sheet product, the inner diameter of the deposition window at the top of the cylindrical silicon nitride ceramic protective cover can only be designed to be smaller than the outer diameter of the standard size substrate sheet. The outer diameter of the gallium nitride single crystal thick film wafer prepared will be smaller than the standard size, and after cutting, grinding and polishing processing, only gallium nitride single crystal sheet material with an outer diameter smaller than the standard size can be obtained, which affects the gallium nitride device process and reduces the number of gallium nitride devices prepared. The present application uses a silicon carbide substrate sheet larger than the standard size to grow a gallium nitride single crystal thick film larger than the standard size on a substrate tray with a cylindrical silicon nitride ceramic protective cover. After cutting, grinding and polishing processing, standard size gallium nitride single crystal sheet material can be obtained, and gallium nitride devices can be prepared on the standard size gallium nitride single crystal sheet material by homoepitaxy, which reduces production cost and improves yield;

[0052] 2. The application can prepare a suitable thickness of ultra-thin porous aluminum oxide weakly bonded decoupling layer and a suitable crystal quality of aluminum nitride single crystal thin film template layer on a non-standard size silicon carbide substrate sheet by adopting a magnetron sputtering and high-temperature high-vacuum annealing combined process, which can realize repeated use of the non-standard size silicon carbide substrate sheet, reduce the production cost of gallium nitride single crystal material, and is also beneficial to improving the preparation and growth quality of thick film gallium nitride single crystal material and the yield;

[0053] 3. Compared with the graphite substrate tray without the cylindrical silicon nitride ceramic protective cover in the prior art, only vertical installation can be achieved, and inverted installation cannot be achieved. When vertically installed, the deposition surface of the silicon carbide substrate sheet faces upward, and in the magnetron sputtering or hydride vapor phase epitaxy process, particulate deposition is prone to occur, which affects the growth quality of the prepared material and reduces the yield of the prepared material. In the application, the inner diameter of the deposition window of the silicon nitride ceramic protective cover is smaller than the outer diameter of the non-standard size silicon carbide substrate sheet and larger than the outer diameter of the standard silicon carbide substrate sheet. When the substrate tray is invertedly installed on the substrate rotation base, the silicon carbide substrate sheet will not fall off. When the substrate tray is invertedly installed, the deposition surface of the silicon carbide substrate sheet faces downward, which can avoid the particulate deposition phenomenon in the magnetron sputtering or hydride vapor phase epitaxy process, and is beneficial to improving the growth uniformity and surface flatness of the prepared material, and is also beneficial to improving the material crystalline quality and material yield.

[0054] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or components referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0055] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, can be fixed connection, or detachable connection, or integrated; can be mechanical connection, or electrical connection or communication with each other; can be directly connected, or indirectly connected through an intermediate medium; can be the internal communication of two components or the interaction relationship between two components, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0056] In this disclosure, the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" mean that a particular feature, structure, material, or characteristic is included in at least one embodiment or example of the present disclosure. The illustrative appearances of the above-mentioned terms in various places in the specification are not necessarily referred to the same embodiment or example. Moreover, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples. Furthermore, the terminology "comprising" is used in the disclosure as comprising but not limited to, that is, it is open-ended and does not exclude the presence of additional features, structures, materials, or characteristics.

[0057] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above-described embodiments are exemplary, and are not to be interpreted as limiting the present disclosure, and the ordinary skilled in the art can make changes, modifications, replacements, and variations to the above-described embodiments within the scope of the present disclosure.

Claims

1. A method for fabricating a gallium nitride single crystal wafer, characterized in that, Includes the following steps: S1: Place a silicon carbide substrate larger than the standard size in the receiving groove of the graphite tray, install a cylindrical silicon nitride ceramic protective cover on the graphite tray, and assemble to obtain the substrate tray. S2: The substrate tray in S1 is inverted and installed on the rotating base of the growth chamber of the magnetron sputtering equipment, and zinc aluminum oxide polycrystalline thin film and aluminum nitride polycrystalline thin film are sequentially prepared on the silicon carbide substrate wafer that is larger than the standard size. S3: After cooling and removing the substrate tray from S2, place it into the high-temperature and high-vacuum annealing furnace chamber for high-temperature and high-vacuum annealing treatment. The zinc aluminum oxide polycrystalline thin film is converted into a porous alumina weak bonding decoupling layer, and the aluminum nitride polycrystalline thin film is converted into an aluminum nitride single crystal template layer. S4: After cooling and removing the substrate tray from S3, invert it and install it on the substrate rotating base in the reaction chamber of the hydride vapor phase epitaxy equipment. Then, deposit a gallium nitride single crystal thick film on the aluminum nitride single crystal template layer using the hydride vapor phase epitaxy process. S5: Cool down and remove the substrate tray from S4, remove the cylindrical silicon nitride ceramic protective cover, and peel off the larger-than-standard-size silicon carbide substrate to obtain a larger-than-standard-size gallium nitride single crystal thick film wafer. S6: The silicon nitride single crystal thick film wafer larger than the standard size is cut, ground, and polished to obtain a gallium nitride single crystal wafer of standard size; S7: High-temperature, high-vacuum baking and cleaning of silicon carbide substrates and cylindrical silicon nitride ceramic protective covers larger than standard sizes under chlorine atmosphere; S8: Repeat steps S1 to S7; In step S1, a deposition window is opened on the cylindrical silicon nitride ceramic protective cover, and the cylindrical silicon nitride ceramic protective cover is flexibly connected to the graphite tray.

2. The method for fabricating gallium nitride single wafers according to claim 1, characterized in that, In step S2, when preparing the zinc-aluminum-oxygen polycrystalline thin film, argon is used as the sputtering gas and oxygen is used as the reaction gas. A zinc-aluminum-oxygen polycrystalline thin film with a thickness of 10-50 nm and an aluminum content of 20-80% is prepared by reactive co-sputtering process using a zinc target and an aluminum target.

3. The method for fabricating gallium nitride single wafers according to claim 1, characterized in that, In step S2, when preparing the aluminum nitride polycrystalline thin film, argon is used as the sputtering gas and nitrogen is used as the reaction gas. The aluminum target reactive sputtering process is used to prepare the aluminum nitride polycrystalline thin film with a thickness of 100-1000 nm.

4. The method for fabricating a gallium nitride single wafer according to claim 1, characterized in that, In step S3, the high-temperature high-vacuum annealing process is as follows: heating to 1400-1600°C in a hydrogen atmosphere and holding at that temperature for 5-10 hours under vacuum.

5. The method for fabricating a gallium nitride single wafer according to claim 1, characterized in that, In step S3, the dislocation density of the aluminum nitride single crystal template layer is less than 5 × 10⁻⁶. 7 cm -2 .

6. The method for fabricating a gallium nitride single wafer according to claim 1, characterized in that, In step S4, the thickness of the gallium nitride single crystal thick film is 300-2000 μm.

7. The method for fabricating a gallium nitride single wafer according to claim 1, characterized in that, In step S6, the dislocation density of a standard-sized gallium nitride single wafer is less than or equal to 1 × 10⁻⁶. 6 cm -2 .

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