Gallium oxide crystal preparation process and device

Abstract

The invention relates to the technical field of gallium oxide crystal preparation, in particular to a gallium oxide crystal preparation process and device. The specific preparation process comprises the following steps: S1, pressing a mixed material into a material blank; s2, performing vacuum impregnation on the blank in a gallium chloride solution; s3, performing vacuum impregnation on the blank in a potassium chloride solution; s4, putting the material blank into a growth furnace, and heating the crucible; s5, controlling the interface growth temperature of the crystal, and growing a gallium oxide crystal; and S6, cooling the crystal obtained in the step S5 in three stages to obtain the gallium oxide crystal. The invention further discloses a preparation device of the gallium oxide crystal preparation process, the preparation device comprises the growth furnace, the growth furnace comprises a base, a bottom support is arranged above the base, a heat preservation base plate is arranged above the bottom support, and a zirconium oxide felt layer is arranged between the lower inner side heat preservation cylinder and the lower outer side heat preservation cylinder in a filling mode. The gallium oxide crystal prepared by the invention has relatively low dislocation density and lattice constant, and the preparation method is simple.

Description

Technical Field

[0001] This invention relates to the field of gallium oxide crystal preparation technology, specifically a gallium oxide crystal preparation process and apparatus. Background Technology

[0002] Gallium oxide (GaO) is a wide-bandgap semiconductor material (bandgap ~4.8 eV). Due to its excellent high-voltage resistance, high-temperature resistance, and ultraviolet photoelectric properties, it has significant application prospects in power electronic devices, deep-ultraviolet detectors, and transparent conductive films. Among them, β-gallium oxide crystals have become a research focus due to their thermodynamic stability. However, the preparation of high-quality β-gallium oxide crystals still faces challenges such as lattice constant deviation and high dislocation density, which affect its electrical and optical properties.

[0003] To address the problems mentioned in the background art, those skilled in the art have proposed a method for preparing gallium oxide crystals, which involves pressing gallium oxide powder of different particle sizes into powder, and then impregnating it with gallium chloride and potassium chloride solutions to effectively reduce the lattice constant and dislocation density of the grown gallium oxide crystals. Summary of the Invention

[0004] The purpose of this invention is to provide a gallium oxide crystal preparation process and apparatus to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A gallium oxide crystal fabrication process includes the following steps: S1. Mix gallium oxide powder of three particle sizes evenly, then add anhydrous ethanol and ball mill for 1-2 hours to obtain a mixture. Press the mixture into a blank under a pressure of 10-50 MPa. S2. The blank obtained in step S1 is completely immersed in gallium chloride solution and vacuum impregnated for 0.5-1h. After impregnation, the blank is heated to 500-700℃ in air at a heating rate of 3℃ / min and held at that temperature for 2-5h. S3. The material blank treated in step S2 is completely immersed in potassium chloride solution and vacuum impregnated for 2-3 hours. After impregnation, the material blank is dried at 120°C until it reaches constant weight. S4. The blank processed in step S3 is placed into the growth furnace for growth. Under the atmosphere of nitrogen and oxygen and the pressure of 2 MPa, the crucible is heated to 1700-1800℃ at a heating rate of 5℃ / min and held for 2-4 hours. S5. Reduce the pressure of the growth furnace in step S4 to 1.4 MPa, control the descent speed to 1 mm / h and the rotation speed to 15 r / min, and maintain the crystal interface temperature at 1650-1750℃ to grow crystals. S6. The crystal obtained in step S5 is cooled in three stages to obtain gallium oxide crystal.

[0006] Furthermore, the three types of gallium nitride powder in step S1 include gallium nitride powder with particle sizes of 0.1-0.5 μm, gallium nitride powder with particle sizes of 1-5 μm, and gallium nitride powder with particle sizes of 10-20 μm.

[0007] Furthermore, in step S1, the ratio of 0.1-0.5μm gallium nitride powder, 1-5μm gallium nitride powder and 10-20μm gallium nitride powder is 1:(3-6):(10-15).

[0008] Furthermore, in step S1, the mass ratio between the total mass of the three types of gallium oxide powder and anhydrous ethanol is (1-2):1.

[0009] Furthermore, in step S2, the gallium chloride solution includes gallium chloride, deionized water, and anhydrous ethanol; the mass ratio of gallium chloride, deionized water, and anhydrous ethanol is 1:(30-50):(5-10); in step S3, the potassium chloride solution includes potassium chloride and deionized water, and the mass ratio of potassium chloride and deionized water is 1:(80-100).

[0010] Furthermore, in step S4, the volume ratio between nitrogen and oxygen is 8:1.

[0011] Furthermore, the three-stage cooling process in step S6 includes first cooling down to 800-1000℃ at a rate of 5℃ / min and holding at that temperature for 1-3 hours; then cooling down to 250-400℃ at a rate of 4℃ / min and holding at that temperature for 0.5-1.5 hours; and finally cooling down to room temperature at a rate of 2℃ / min.

[0012] A gallium oxide crystal preparation apparatus includes the aforementioned growth furnace. The growth furnace includes a base, a base support is provided above the base, a heat insulation pad is provided above the base support, a lower inner heat insulation cylinder and a lower outer heat insulation cylinder are sequentially arranged outside the heat insulation pad, a zirconium oxide felt layer is filled between the lower inner heat insulation cylinder and the lower outer heat insulation cylinder, an upper cover plate is provided above the lower inner heat insulation cylinder and the lower outer heat insulation cylinder, a temperature control plate is also provided on the upper cover plate, and an upper inner heat insulation cylinder and an upper outer heat insulation cylinder are sequentially arranged from the inside to the outside above the upper cover plate, a top cover plate is provided above the upper inner heat insulation cylinder and the upper outer heat insulation cylinder, and a top temperature control plate is provided above the top cover plate.

[0013] Furthermore, an anti-diffusion evaporation hood is provided on the outside of the upper outer insulation cylinder. The anti-diffusion evaporation hood is used to fix the seed crystal and insert it downwards for gallium oxide crystal generation.

[0014] Compared with the prior art, the beneficial effects of the present invention are: In this invention, gallium oxide crystals of different particle sizes are pressed into blanks, and then impregnated successively with gallium chloride solution and potassium chloride solution, which can effectively reduce the lattice constant and dislocation density of the prepared gallium oxide crystals. Attached Figure Description

[0015] Figure 1 This is a process flow diagram for preparing gallium oxide crystals according to the present invention; Figure 2 This is a schematic diagram of the overall structure of the preparation apparatus of the present invention.

[0016] In the diagram: 1. Base, 2. Base support, 3. Insulation pad, 4. Lower outer insulation cylinder, 5. Lower inner insulation cylinder, 6. Zirconia felt layer, 7. Top cover, 8. Temperature control plate, 9. Upper outer insulation cylinder, 10. Upper inner insulation cylinder, 11. Top cover, 12. Top temperature control plate, 13. Anti-diffusion evaporation cover, 14. Seed crystal, 15. Gallium oxide crystal. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figure 1-2 The present invention provides: Example 1 A gallium oxide crystal fabrication process includes the following steps: S1. Gallium oxide powders with particle sizes of 0.2μm, 3μm and 15μm are mixed evenly. The amounts of gallium oxide powders with particle sizes of 0.2μm, 3μm and 15μm are 4g, 22g and 46g respectively. Then, 48g of anhydrous ethanol is added and ball-milled for 1.5h to obtain a mixture. The mixture is pressed into a blank under a pressure of 20MPa. S2. The blank obtained in step S1 is completely immersed in a gallium chloride solution and vacuum impregnated for 0.8 h. The gallium chloride solution contains gallium chloride, deionized water and anhydrous ethanol. The mass ratio of gallium chloride, deionized water and anhydrous ethanol is 1:40:6. The impregnated blank is heated to 650°C in air at a heating rate of 3°C / min and held at that temperature for 4 h. S3. The material blank treated in step S2 is completely immersed in a potassium chloride solution and vacuum impregnated for 2.5 hours. The potassium chloride solution contains potassium chloride and deionized water, and the mass ratio between potassium chloride and deionized water is 1:95. After impregnation, the material blank is dried at 120°C to constant weight. S4. The blank processed in step S3 is placed into the growth furnace for growth. Under the atmosphere of nitrogen and oxygen and the pressure of 2 MPa, the volume ratio of nitrogen to oxygen is 8:1. The crucible is heated to 1780℃ and held for 3.5h at a heating rate of 5℃ / min. S5. Reduce the pressure of the growth furnace in step S4 to 1.4 MPa, control the descent speed to 1 mm / h and the rotation speed to 15 r / min, and maintain the crystal interface temperature at 1720℃ to grow crystals. S6. The crystal obtained in step S5 is cooled in three stages to obtain gallium oxide crystal; The three-stage cooling process in step S6 above includes first cooling down to 950℃ at a rate of 5℃ / min and holding at that temperature for 1.6h; then cooling down to 360℃ at a rate of 4℃ / min and holding at that temperature for 1.2h; and finally cooling down to room temperature at a rate of 2℃ / min.

[0019] Example 2 A gallium oxide crystal fabrication process includes the following steps: S1. Gallium oxide powders with particle sizes of 0.1μm, 1μm and 10μm are mixed evenly. The amounts of gallium oxide powders with particle sizes of 0.1μm, 1μm and 10μm are 4g, 12g and 40g respectively. Then, 56g of anhydrous ethanol is added and ball-milled for 1h to obtain a mixture. The mixture is pressed into a blank under a pressure of 10MPa. S2. The blank obtained in step S1 is completely immersed in gallium chloride solution and vacuum impregnated for 0.5h. The gallium oxide solution contains gallium chloride, deionized water and anhydrous ethanol. The mass ratio between gallium chloride, deionized water and anhydrous ethanol is 1:30:5. The impregnated blank is heated to 500℃ in air at a heating rate of 3℃ / min and held at that temperature for 2h. S3. The material blank treated in step S2 is completely immersed in a potassium chloride solution and vacuum impregnated for 2 hours. The potassium chloride solution contains potassium chloride and deionized water, and the mass ratio between potassium chloride and deionized water is 1:80. After impregnation, the material blank is dried at 120°C to constant weight. S4. The blank processed in step S3 is placed into the growth furnace for growth. Under the atmosphere of nitrogen and oxygen and the pressure of 2 MPa, the volume ratio between nitrogen and oxygen is 8:1. The crucible is heated to 1700℃ and held for 2 hours at a heating rate of 5℃ / min. S5. Reduce the pressure of the growth furnace in step S4 to 1.4 MPa, control the descent speed to 1 mm / h and the rotation speed to 15 r / min, and maintain the crystal interface temperature at 1650℃ to grow crystals. S6. The crystal obtained in step S5 is cooled in three stages to obtain gallium oxide crystal; The three-stage cooling process in step S6 above includes first cooling down to 800℃ at a rate of 5℃ / min and holding at that temperature for 1 hour; then cooling down to 250℃ at a rate of 4℃ / min and holding at that temperature for 0.5 hours; and finally cooling down to room temperature at a rate of 2℃ / min.

[0020] Example 3 A gallium oxide crystal fabrication process includes the following steps: S1. Gallium oxide powders with particle sizes of 0.5μm, 5μm and 20μm are mixed evenly. The amounts of gallium oxide powders with particle sizes of 0.5μm, 5μm and 20μm are 4g, 24g and 60g respectively. Then, 44g of anhydrous ethanol is added and ball-milled for 2h to obtain a mixture. The mixture is pressed into a blank under a pressure of 50MPa. S2. The blank obtained in step S1 is completely immersed in a gallium chloride solution and vacuum impregnated for 1 hour. The gallium chloride solution contains gallium chloride, deionized water and anhydrous ethanol. The mass ratio of gallium chloride, deionized water and anhydrous ethanol is 1:50:10. The impregnated blank is heated to 700°C in air at a heating rate of 3°C / min and kept at that temperature for 5 hours. S3. The material blank treated in step S2 is completely immersed in a potassium chloride solution and vacuum impregnated for 3 hours. The potassium chloride solution contains potassium chloride and deionized water, and the mass ratio between potassium chloride and deionized water is 1:100. After impregnation, the material blank is dried at 120°C to constant weight. S4. The blank processed in step S3 is placed into the growth furnace for growth. Under the atmosphere of nitrogen and oxygen and the pressure of 2 MPa, the volume ratio between nitrogen and oxygen is 8:1. The crucible is heated to 1800℃ and held for 4 hours at a heating rate of 5℃ / min. S5. Reduce the pressure of the growth furnace in step S4 to 1.4 MPa, control the descent speed to 1 mm / h and the rotation speed to 15 r / min, and maintain the crystal interface temperature at 1750℃ to grow crystals. S6. The crystal obtained in step S5 is cooled in three stages to obtain gallium oxide crystal; The three-stage cooling process in step S6 above includes first cooling down to 1000℃ at a rate of 5℃ / min and holding at that temperature for 3 hours; then cooling down to 400℃ at a rate of 4℃ / min and holding at that temperature for 1.5 hours; and finally cooling down to room temperature at a rate of 2℃ / min.

[0021] Example 4 A gallium oxide crystal fabrication process includes the following steps: S1. Gallium oxide powders with particle sizes of 0.4μm, 3μm and 15μm are mixed evenly. The amounts of gallium oxide powders with particle sizes of 0.4μm, 3μm and 15μm are 4g, 20g and 48g respectively. Then, 36g of anhydrous ethanol is added and the mixture is ball-milled for 1.8h to obtain a mixture. The mixture is pressed into a blank under a pressure of 30MPa. S2. The blank obtained in step S1 is completely immersed in a gallium chloride solution and vacuum impregnated for 0.6 h. The gallium chloride solution contains gallium chloride, deionized water and anhydrous ethanol. The mass ratio of gallium chloride, deionized water and anhydrous ethanol is 1:45:8. The impregnated blank is heated to 550°C in air at a heating rate of 3°C / min and held at that temperature for 4.5 h. S3. The material blank treated in step S2 is completely immersed in a potassium chloride solution and vacuum impregnated for 2.2 hours. The potassium chloride solution contains potassium chloride and deionized water, and the mass ratio between potassium chloride and deionized water is 1:85. After impregnation, the material blank is dried at 120°C to constant weight. S4. The blank processed in step S3 is placed into the growth furnace for growth. Under the atmosphere of nitrogen and oxygen and the pressure of 2 MPa, the volume ratio between nitrogen and oxygen is 8:1. The crucible is heated to 1760℃ and held for 3 hours at a heating rate of 5℃ / min. S5. Reduce the pressure of the growth furnace in step S4 to 1.4 MPa, control the descent speed to 1 mm / h and the rotation speed to 15 r / min, and maintain the crystal interface temperature at 1680℃ to grow crystals. S6. The crystal obtained in step S5 is cooled in three stages to obtain gallium oxide crystal; The three-stage cooling process in appeal step S6 includes first cooling down to 880℃ at a rate of 5℃ / min and holding for 2 hours; then cooling down to 330℃ at a rate of 4℃ / min and holding for 1.1 hours; and finally cooling down to room temperature at a rate of 2℃ / min.

[0022] Reference Attachment to the Structure of Gallium Oxide Crystal Fabrication Apparatus Figure 2As shown, the device includes the aforementioned growth furnace, which includes a base 1. A base support 2 is provided above the base 1, and a multi-layered insulation pad 3 is provided above the base support 2. A lower inner insulation cylinder 5 and a lower outer insulation cylinder 4 are sequentially arranged outside the insulation pad 3. The lower inner insulation cylinder 5 and the lower outer insulation cylinder 4 can insulate the lower part of the temperature field. A zirconia felt layer 6 is filled between the lower inner insulation cylinder 5 and the lower outer insulation cylinder 4. The zirconia further enhances the insulation of the temperature field. An upper cover plate 7 is provided above the inner insulation cylinder 5 and the lower outer insulation cylinder 4. A temperature control plate 8 is also provided on the upper cover plate 7. By adjusting the inner diameter of the temperature control plate 8, the problem of the seed crystal 14 melting without expanding and then rapidly expanding when cooled during the crystal production process can be solved. It can also solve the problem of the shoulder not expanding, rapidly expanding or being pulled off when the shoulder length is within the corresponding predetermined length during the shoulder formation process when the diameter is between 15mm and 45mm.

[0023] An upper inner insulation cylinder 10 and an upper outer insulation cylinder 9 are arranged sequentially from the inside to the outside above the upper cover plate 7. A top cover plate 11 is arranged above the upper inner insulation cylinder 10 and the upper outer insulation cylinder 9. A top temperature control plate 12 is arranged above the top cover plate 11. The setting and adjustment of the top temperature control plate 12 can control the heat dissipation rate of the crystal by adjusting its inner diameter, thus solving the problems of overcooling and cracking of the crystal components.

[0024] An anti-diffusion evaporation hood 13 is provided on the outside of the upper outer insulation cylinder 9. The anti-diffusion evaporation hood 13 is used to fix the seed crystal 14 and insert it downwards for the formation of gallium oxide crystal 15. When the anti-diffusion evaporation hood 13 is used, it can effectively reduce the volatiles in the furnace. By adjusting the gallium oxide temperature field, it reduces the growth defects inside the gallium oxide crystal and solves the problem of pull-out phenomenon in the automated growth of gallium oxide crystal.

[0025] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the three types of gallium oxide particles used in step S1 were replaced with 0.2 μm gallium oxide particles, and the amount was 72 g. The rest of the steps were exactly the same as in Example 1.

[0026] Comparative Example 2 The difference between Comparative Example 1 and Example 1 is that the three types of gallium oxide particles used in step S1 were replaced with 3μm gallium oxide particles, and the amount was 72g. The rest of the steps were exactly the same as in Example 1.

[0027] Comparative Example 3 The difference between Comparative Example 1 and Example 1 is that the three types of gallium oxide particles used in step S1 were replaced with 15μm gallium oxide particles, and the amount was 72g. The remaining steps were exactly the same as in Example 1.

[0028] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the hollow impregnation in gallium chloride solution in step S2 is replaced by vacuum impregnation in a mixed solution of deionized water and anhydrous ethanol, with a mass ratio of deionized water to anhydrous ethanol of 20:3. The remaining steps are exactly the same as in Example 1.

[0029] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the vacuum impregnation in gallium chloride solution in step S3 is replaced by vacuum impregnation in deionized water, while the remaining steps are exactly the same as in Example 1.

[0030] The lattice constant and dislocation density of the gallium oxide crystals prepared in Examples 1-4 and Comparative Examples 1-5 were measured. The lattice constant was determined by X-ray diffraction, and the dislocation density was measured according to the standard GB / T 32282-2015 "Measurement of Dislocation Density of Gallium Nitride Single Crystal". The measurement results are shown in Table 1 below: Table 1: Lattice constant and dislocation density test results of gallium oxide crystals prepared in Examples 1-4 and Comparative Examples 1-5

[0031] As can be seen from the data in Table 1 above, by setting gallium oxide powder of different particle sizes for doping growth in this invention, the lattice constant and dislocation density of the prepared gallium oxide crystal can be effectively reduced; in addition, after the preform is impregnated with gallium chloride solution and potassium chloride solution, the lattice constant and dislocation density of the prepared gallium oxide crystal can also be reduced.

[0032] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for preparing a gallium oxide crystal, characterized by, Includes the following steps: S1. Mix gallium oxide powder of three particle sizes evenly, then add anhydrous ethanol and ball mill for 1-2 hours to obtain a mixture. Press the mixture into a blank under a pressure of 10-50 MPa. S2. The blank obtained in step S1 is completely immersed in gallium chloride solution and vacuum impregnated for 0.5-1h. After impregnation, the blank is heated to 500-700℃ in air at a heating rate of 3℃ / min and held at that temperature for 2-5h. S3. The blank treated in step S2 is completely immersed in potassium chloride solution and vacuum impregnated for 2-3 hours. After impregnation, the blank is dried at 120°C until it reaches constant weight to obtain seed crystals. S4. Place the seed crystal treated in step S3 into the growth furnace for growth. In an atmosphere of nitrogen and oxygen and a pressure of 2 MPa, heat the crucible to 1700-1800℃ at a heating rate of 5℃ / min and hold for 2-4 hours. S5. Reduce the pressure of the growth furnace in step S4 to 1.4 MPa, control the descent speed to 1 mm / h and the rotation speed to 15 r / min, and maintain the crystal interface temperature at 1650-1750℃ to grow crystals. S6. The crystal obtained in step S5 is cooled in three stages to obtain gallium oxide crystal.

2. The process for preparing gallium oxide crystal according to claim 1, wherein The gallium nitride powders of the three particle sizes in step S1 include gallium nitride powders of 0.1-0.5 μm, gallium nitride powders of 1-5 μm, and gallium nitride powders of 10-20 μm.

3. The process for preparing gallium oxide crystal according to claim 2, wherein In step S1, the ratio of 0.1-0.5μm gallium nitride powder, 1-5μm gallium nitride powder and 10-20μm gallium nitride powder is 1:(3-6):(10-15).

4. The process for preparing gallium oxide crystal according to claim 2, wherein In step S1, the mass ratio of the total mass of gallium oxide powder of the three particle sizes to anhydrous ethanol is (1-2):

1.

5. The process for preparing gallium oxide crystal according to claim 2, wherein The gallium chloride solution in step S2 includes gallium chloride, deionized water and anhydrous ethanol; the mass ratio of gallium chloride, deionized water and anhydrous ethanol is 1:(30-50):(5-10); the potassium chloride solution in step S3 includes potassium chloride and deionized water, and the mass ratio of potassium chloride and deionized water is 1:(80-100).

6. The process for preparing gallium oxide crystal according to claim 2, wherein In step S4, the volume ratio of nitrogen to oxygen is 8:

1.

7. The gallium oxide crystal preparation process according to claim 2, characterized in that, The three-stage cooling process in step S6 includes: first, cooling down to 800-1000℃ at a rate of 5℃ / min and holding for 1-3 hours; then cooling down to 250-400℃ at a rate of 4℃ / min and holding for 0.5-1.5 hours; and finally cooling down to room temperature at a rate of 2℃ / min.

8. A preparation apparatus based on the gallium oxide crystal preparation process according to any one of claims 1-7, characterized in that: The device includes the aforementioned growth furnace, which includes a base, a base support above the base, an insulation pad above the base support, a lower inner insulation cylinder and a lower outer insulation cylinder arranged sequentially on the outer side of the insulation pad, a zirconia felt layer filled between the lower inner and lower outer insulation cylinders, an upper cover plate above the lower inner and lower outer insulation cylinders, a temperature control plate also provided on the upper cover plate, and an upper inner insulation cylinder and an upper outer insulation cylinder arranged sequentially from the inside to the outside above the upper cover plate, a top cover plate above the upper inner and upper outer insulation cylinders, and a top temperature control plate above the top cover plate.

9. The gallium oxide crystal preparation apparatus according to claim 8, characterized in that: An anti-diffusion evaporation hood is provided on the outside of the upper outer insulation cylinder. The anti-diffusion evaporation hood is used to fix the seed crystal and insert it downwards for gallium oxide crystal generation.

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