Flux for growth of gallium oxide crystal and growth method

Abstract

The invention relates to a fluxing agent for gallium oxide crystal growth and a growth method. The fluxing agent for growth of the gallium oxide crystal comprises vanadium pentoxide or a mixture composed of vanadium pentoxide and boron oxide. The fluxing agent does not contain toxic and harmful components such as lead oxide and lead fluoride, gallium oxide crystals can grow at a moderate temperature, volatilization and decomposition reactions of gallium oxide during high-temperature growth are effectively inhibited, and component segregation of the crystals in the growth process is improved; the gallium oxide crystal has relatively low viscosity, is beneficial to solute transportation in a crystal growth process, and can effectively reduce or even eliminate inclusion defects in the gallium oxide crystal; the method has a wide crystallization temperature interval, can improve the stability of crystal growth, and is beneficial to obtaining large-size and high-quality gallium oxide crystals.

Description

Technical Field

[0001] The invention relates to the field of crystal growth, and in particular to a flux for growing gallium oxide crystals and a growth method. Background Art

[0002] Gallium oxide crystal is a fourth-generation wide bandgap semiconductor material with a bandgap width of 4.9eV. Compared with the third-generation semiconductor silicon carbide and gallium nitride materials, gallium oxide has a wider bandgap, higher breakdown voltage and lower loss. It is an ideal material second only to diamond in terms of voltage resistance and power. Therefore, it can be used to prepare high-voltage, high-power, and low-loss power devices. In addition, the ultraviolet cutoff edge of gallium oxide is about 250nm, which can be used in optical communications and optoelectronic devices in the deep ultraviolet band. Therefore, gallium oxide crystal has become one of the hot spots in the field of semiconductor materials and has received widespread attention.

[0003] Gallium oxide is a uniformly molten compound with a melting point of about 1800°C. Crystals are usually prepared by the melt method. The main growth methods include the guided mold method, the pulling method, the floating zone method, etc. In a high-temperature, oxygen-deficient environment, gallium oxide will undergo a decomposition reaction, and the decomposition products are volatile metal gallium and gallium oxides. Especially when the temperature exceeds 1680°C, the decomposition reaction is more intense. At present, the most important growth method of gallium oxide, the guided mold method, uses iridium as the crucible. The metal gallium produced by high-temperature decomposition will corrode the iridium crucible used to grow crystals, causing serious iridium loss. In addition, the decomposition products will cause a large number of defects in the crystal, which will significantly affect the quality of the gallium oxide crystal and then affect the performance of subsequent devices. Therefore, it is necessary to reduce the growth temperature of gallium oxide crystals. As early as the 1960s, researchers proposed the use of flux method to grow gallium oxide crystals (J.Am.Ceram.Soc., 1964, 47: 537-538; J.Am.Ceram.Soc., 1966, 49: 168-169). This method can effectively reduce the growth temperature, but the flux system is composed of toxic and harmful compounds such as lead oxide and lead fluoride, and the grown crystals contain macroscopic defects such as inclusions and clouds, which affect the crystal quality and available size.

[0004] In view of this, finding a suitable flux system is the key to achieving the flux method for growing high-quality gallium oxide crystals. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a flux and a growth method for gallium oxide crystal growth, aiming to solve the problems that the existing gallium oxide crystal growth temperature is too high and the crystal quality is not high.

[0006] The technical solution of the present invention is as follows:

[0007] A flux for growing gallium oxide crystals, comprising vanadium pentoxide or a mixture of vanadium pentoxide and boron oxide.

[0008] Specifically, the molar ratio of vanadium pentoxide to boron oxide is 1:(0-0.30).

[0009] Specifically, the molar ratio of vanadium pentoxide to boron oxide is 1:(0.05-0.30).

[0010] The application of vanadium pentoxide as a flux in the growth of gallium oxide crystals. During the crystal growth, the molar ratio of gallium oxide raw material to vanadium pentoxide is (0.4-0.8):1.

[0011] Specifically, the molar ratio of the gallium oxide raw material, vanadium pentoxide and boron oxide is (0.4-0.8):1:(0.05-0.30).

[0012] A method for growing gallium oxide crystals comprises the following steps:

[0013] Step 1: uniformly mixing a gallium oxide raw material and the flux according to any one of claims 1 to 3 to obtain a mixed raw material;

[0014] Step 2: pour the mixed raw material obtained in step 1 into a crucible and heat it to melt, then test the saturation point temperature and introduce gallium oxide seed crystals;

[0015] Step 3: Taking the saturation point temperature as the starting temperature, cooling down and rotating the gallium oxide seed crystal at the same time, growing the gallium oxide crystal on the gallium oxide seed crystal until the gallium oxide crystal on the gallium oxide seed crystal grows to a desired size, and the growth is terminated.

[0016] Specifically, the crucible is a platinum crucible.

[0017] Specifically, the temperature of heating and melting in step 2 is 1020-1250°C.

[0018] Specifically, the saturation point temperature of the melt in step 2 is 950-1150°C.

[0019] Specifically, the rotation speed of the gallium oxide seed crystal in step 3 is 5-15 rpm.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The flux system of the present invention does not contain toxic and harmful components such as lead oxide and lead fluoride, and can grow gallium oxide crystals at a moderate temperature, effectively inhibit the volatilization and decomposition reaction of gallium oxide during high-temperature growth, and improve the component segregation of the crystal during the growth process.

[0022] 2. The flux system of the present invention has a relatively low viscosity, which is beneficial to the solute transport during the crystal growth process and can effectively reduce or even eliminate inclusion defects in gallium oxide crystals.

[0023] 3. The flux system of the present invention has a wide crystallization temperature range, which can improve the stability of crystal growth and is conducive to obtaining large-sized, high-quality gallium oxide crystals.

[0024] 4. The crucible used in the crystal growth method of the present invention is a platinum crucible. Compared with the iridium crucible used in the most important growth method, the guided mold method, the thickness of the platinum crucible is less than half of the iridium crucible. Under the conditions of the same diameter and height, the cost of the crucible is about one-tenth of that of the iridium crucible, thus having a significant advantage in the production cost of gallium oxide crystals. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a photo of the gallium oxide crystal grown in Example 4 of the present invention.

[0026] Figure 2 This is the X-ray rocking curve of the gallium oxide crystal grown in Example 4 of the present invention. DETAILED DESCRIPTION

[0027] The present invention provides a flux and a growth method for gallium oxide crystal growth. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] This embodiment provides a flux for growing gallium oxide crystals, including vanadium pentoxide or a mixture of vanadium pentoxide and boron oxide.

[0029] The melting point of vanadium pentoxide is about 690℃. By adjusting the ratio of vanadium pentoxide and gallium oxide raw materials, the melting temperature of the mixed raw materials can be reduced to below the upper temperature limit (1250℃) of long-term use of ordinary resistance wire. Vanadium pentoxide and gallium oxide will not react to form new compounds under normal pressure conditions. Therefore, using vanadium pentoxide as a flux can grow gallium oxide crystals in a wider temperature range.

[0030] The melting point of boron oxide is about 450°C. By adjusting the ratio of the flux composed of vanadium pentoxide and boron oxide and the gallium oxide raw material, the melting temperature of the mixed raw materials can be further reduced. Boron oxide and gallium oxide may form GaBO3 compounds below 920°C, so the raw material ratio can be adjusted to make gallium oxide grow within the temperature range of 920-1150°C. The flux system composed above has a wide gallium oxide growth temperature range, which can improve the stability of crystal growth, and has a small viscosity, which is conducive to the transport of solutes, so that large-sized, high-quality gallium oxide crystals can be grown.

[0031] In one embodiment, the molar ratio of vanadium pentoxide to boron oxide is 1:(0-0.30).

[0032] In one embodiment, the molar ratio of vanadium pentoxide to boron oxide is 1:(0.05-0.30).

[0033] Specifically, during crystal growth, the molar ratio of gallium oxide raw material, vanadium pentoxide and boron oxide is (0.4-0.8):1:(0-0.30).

[0034] A method for growing gallium oxide crystals comprises the following steps:

[0035] Step 1: uniformly mixing a gallium oxide raw material and the flux according to any one of claims 1 to 3 to obtain a mixed raw material;

[0036] Step 2: pour the mixed raw material obtained in step 1 into a crucible and heat it to melt, then test the saturation point temperature and introduce gallium oxide seed crystals;

[0037] Step 3: Taking the saturation point temperature as the starting temperature, cooling down and rotating the gallium oxide seed crystal at the same time, growing the gallium oxide crystal on the gallium oxide seed crystal until the gallium oxide crystal on the gallium oxide seed crystal grows to a desired size, and the growth is terminated.

[0038] Step 2 specifically comprises: pouring the mixed raw material obtained in step 1 into a platinum crucible and placing it into a crystal growth furnace, starting the crystal growth furnace to heat up and melt the mixed raw material, and keeping the temperature constant for 20-30 hours to obtain a melt; then testing the saturation point temperature of the melt; then adjusting the temperature to 1-3°C higher than the saturation point temperature, then immersing the gallium oxide seed crystal in the melt, keeping the temperature constant for 15-30 minutes, and then cooling to the saturation point temperature;

[0039] Step 3 specifically includes: starting from the saturation point temperature, cooling at a rate of 0.3-2.0°C / day, rotating the gallium oxide seed crystal, and after the gallium oxide crystal on the gallium oxide seed crystal grows to a desired size, lifting the gallium oxide crystal until it is separated from the melt surface, and finally cooling to room temperature at a rate of 15-50°C / hour, the growth is terminated, and the gallium oxide crystal is obtained.

[0040] In one embodiment, the temperature of the heating and melting in step 2 is 1020-1250°C.

[0041] In one embodiment, the saturation point temperature of the melt in step 2 is 950-1150°C.

[0042] In one embodiment, the rotation speed of the gallium oxide seed crystal in step 3 is 5-15 rpm.

[0043] Gallium oxide, vanadium pentoxide, and boron oxide used in the following examples are all commercially available raw materials with a purity of not less than 99.9%.

[0044] Example 1

[0045] According to the molar ratio of gallium oxide, vanadium pentoxide and boron oxide of 0.6:1:0, 562.5 grams of gallium oxide and 909.5 grams of vanadium pentoxide raw materials were weighed respectively, and placed in a mixer to be fully mixed;

[0046] Pour the mixed raw materials into Φ100×80mm in batches. 3 Put the raw materials into a platinum crucible, put it into a muffle furnace, heat it to 1125℃, keep it at this temperature for 2 hours to melt the raw materials, then cool it to room temperature, and repeat this process until all the raw materials are added into the platinum crucible;

[0047] Put the platinum crucible into the crystal growth furnace, raise the temperature to 1180°C, melt the above raw materials into solution, keep the temperature constant for 20 hours, and obtain a uniform melt;

[0048] The temperature of the melt was gradually lowered, and the saturation point temperature of the melt was determined to be 1095°C by the seed crystal trial method. The melt temperature was adjusted to 1096.5°C (1.5°C higher than the saturation point temperature), and then the seed crystal for crystal growth was slowly immersed in the melt, and the seed crystal was rotated at a speed of 8 rpm. After the temperature was kept constant for 20 minutes, the melt temperature was adjusted to the saturation point temperature of 1095°C.

[0049] The temperature was lowered at a rate of 0.3°C / day. After the gallium oxide crystals grew to the desired size, the rotation speed was adjusted to 5 rpm. The crystals were then pulled off the liquid surface and first cooled to 800°C at a rate of 20°C / hour, and then to room temperature at a rate of 50°C / hour to obtain gallium oxide crystals. Figure 1 Crystals of basically consistent quality.

[0050] Example 2

[0051] According to the molar ratio of gallium oxide, vanadium pentoxide and boron oxide of 0.4:1:0, 404.8 grams of gallium oxide and 982.3 grams of vanadium pentoxide raw materials were weighed respectively, and placed in a mixer to be fully mixed;

[0052] Pour the mixed raw materials into Φ100×80mm in batches. 3 Put the raw materials into a platinum crucible, put it into a muffle furnace, heat it to 1030℃, keep it at this temperature for 2 hours to melt the raw materials, then cool it to room temperature, and repeat this process until all the raw materials are added into the platinum crucible;

[0053] Put the platinum crucible into a crystal growth furnace, raise the temperature to 1080°C, melt the above raw materials completely into a solution, and keep the temperature constant for 25 hours to obtain a uniform melt;

[0054] The temperature of the melt was gradually lowered, and the saturation point temperature of the melt was determined to be 1001°C by the seed crystal trial method. The melt temperature was adjusted to 1003°C (2°C higher than the saturation point temperature), and then the seed crystal for crystal growth was slowly immersed in the melt, and the seed crystal was rotated at a speed of 15 rpm. After the temperature was kept constant for 15 minutes, the melt temperature was adjusted to the saturation point temperature of 1001°C.

[0055] The temperature was lowered at a rate of 2.0°C / day. After the gallium oxide crystals grew to the desired size, the rotation speed was adjusted to 10 rpm, and then the crystals were pulled off the liquid surface and cooled to room temperature at a rate of 50°C / hour. The growth was completed and the gallium oxide crystals were obtained. Figure 1 Crystals of basically consistent quality.

[0056] Example 3

[0057] According to the molar ratio of gallium oxide, vanadium pentoxide and boron oxide of 0.8:1:0, 689.8 grams of gallium oxide and 836.8 grams of vanadium pentoxide raw materials were weighed respectively, and placed in a mixer to be fully mixed;

[0058] Pour the mixed raw materials into Φ100×80mm in batches. 3 Put the raw materials into a platinum crucible, put it into a muffle furnace, heat it to 1200℃, keep it at this temperature for 2 hours to melt the raw materials, then cool it to room temperature, and repeat this process until all the raw materials are added into the platinum crucible;

[0059] Put the platinum crucible into a crystal growth furnace, raise the temperature to 1250°C, melt the above raw materials completely into a solution, and keep the temperature constant for 30 hours to obtain a uniform melt;

[0060] The temperature of the melt was gradually lowered, and the saturation point temperature of the melt was determined to be 1150°C by the seed crystal trial method. The melt temperature was adjusted to 1151°C (1°C higher than the saturation point temperature), and then the seed crystal for crystal growth was slowly immersed in the melt, and the seed crystal was rotated at a speed of 8 rpm. After the temperature was kept constant for 30 minutes, the melt temperature was adjusted to the saturation point temperature of 1150°C.

[0061] The temperature was lowered at a rate of 0.5°C / day. After the gallium oxide crystals grew to the desired size, the rotation speed was adjusted to 15 rpm. The crystals were then pulled off the liquid surface and cooled to room temperature at a rate of 15°C / hour. The growth was completed and the gallium oxide crystals were obtained. Figure 1 Crystals of basically consistent quality.

[0062] Example 4

[0063] According to the molar ratio of gallium oxide, vanadium pentoxide and boron oxide of 0.8:1:0.05, 689.8 grams of gallium oxide, 836.8 grams of vanadium pentoxide and 16.0 grams of boron oxide raw materials were weighed respectively, and placed in a mixer to be fully mixed;

[0064] Pour the mixed raw materials into Φ100×80mm in batches. 3 Put the raw materials into a platinum crucible, put it into a muffle furnace, heat it to 1190℃, keep it at this temperature for 2 hours to melt the raw materials, then cool it to room temperature, and repeat this process until all the raw materials are added into the platinum crucible;

[0065] Put the platinum crucible into a crystal growth furnace, raise the temperature to 1250°C, melt the above raw materials completely into a solution, and keep the temperature constant for 30 hours to obtain a uniform melt;

[0066] The temperature of the melt was gradually lowered, and the saturation point temperature of the melt was determined to be 1146°C by the seed crystal trial method. The melt temperature was adjusted to 1147°C (1°C higher than the saturation point temperature), and then the seed crystal for crystal growth was slowly immersed in the melt, and the seed crystal was rotated at a speed of 8 rpm. After the temperature was kept constant for 15 minutes, the melt temperature was adjusted to the saturation point temperature of 1146°C.

[0067] The temperature was lowered at a rate of 0.5°C / day. After the gallium oxide crystals grew to the desired size, the rotation speed was adjusted to 5 rpm. The crystals were then pulled out of the liquid surface and first cooled to 800°C at a rate of 15°C / hour, and then to room temperature at a rate of 50°C / hour to obtain gallium oxide crystals. The photo is shown in FIG. Figure 1 The rocking curve of the (400) crystal plane of the gallium oxide crystal was tested by X-ray diffractometer, as shown in FIG. Figure 2 As shown, the half-width at half maximum of the rocking curve is 0.02°, that is, 72 arcsec, indicating that the crystal has high crystalline quality.

[0068] Example 5

[0069] According to the molar ratio of gallium oxide, vanadium pentoxide and boron oxide of 0.6:1:0.15, 562.5 grams of gallium oxide, 909.5 grams of vanadium pentoxide and 52.2 grams of boron oxide raw materials were weighed respectively, and placed in a mixer to be fully mixed;

[0070] Pour the mixed raw materials into Φ100×80mm in batches. 3 Put the raw materials into a platinum crucible, put it into a muffle furnace, heat it to 1100℃, keep it at this temperature for 2 hours to melt the raw materials, then cool it to room temperature, and repeat this process until all the raw materials are added into the platinum crucible;

[0071] Put the platinum crucible into a crystal growth furnace, raise the temperature to 1150°C, melt the above raw materials completely into a solution, and keep the temperature constant for 20 hours to obtain a uniform melt;

[0072] The temperature of the melt was gradually lowered, and the saturation point temperature of the melt was determined to be 1068°C by the seed crystal trial method. The melt temperature was adjusted to 1070°C (2°C higher than the saturation point temperature), and then the seed crystal for crystal growth was slowly immersed in the melt, and the seed crystal was rotated at a speed of 10 rpm. After the temperature was kept constant for 25 minutes, the melt temperature was adjusted to the saturation point temperature of 1068°C.

[0073] The temperature was lowered at a rate of 0.7°C / day. After the gallium oxide crystals grew to the desired size, the rotation speed was adjusted to 5 rpm. The crystals were then pulled off the liquid surface and first cooled to 800°C at a rate of 20°C / hour, and then to room temperature at a rate of 50°C / hour to obtain gallium oxide crystals. Figure 1 Crystals of basically consistent quality.

[0074] Example 6

[0075] According to the molar ratio of gallium oxide, vanadium pentoxide and boron oxide of 0.8:1:0.20, 675.0 grams of gallium oxide, 818.6 grams of vanadium pentoxide and 62.6 grams of boron oxide raw materials were weighed respectively, and placed in a mixer to be fully mixed;

[0076] Pour the mixed raw materials into Φ100×80mm in batches. 3 Put the raw materials into a platinum crucible, put it into a muffle furnace, heat it to 1180℃, keep it at this temperature for 2 hours to melt the raw materials, then cool it to room temperature, and repeat this process until all the raw materials are added into the platinum crucible;

[0077] Put the platinum crucible into the crystal growth furnace, raise the temperature to 1225°C, melt the above raw materials into solution, keep the temperature constant for 25 hours, and obtain a uniform melt;

[0078] The temperature of the melt was gradually lowered, and the saturation point temperature of the melt was determined to be 1132°C by the seed crystal trial method. The melt temperature was adjusted to 1134°C (2°C higher than the saturation point temperature), and then the seed crystal for crystal growth was slowly immersed in the melt, and the seed crystal was rotated at a speed of 12 rpm. After the temperature was kept constant for 20 minutes, the melt temperature was adjusted to the saturation point temperature of 1132°C.

[0079] The temperature was lowered at a rate of 1.0°C / day. After the gallium oxide crystals grew to the desired size, the rotation speed was adjusted to 5 rpm. The crystals were then pulled off the liquid surface and first cooled to 800°C at a rate of 20°C / hour, and then cooled to room temperature at a rate of 50°C / hour to obtain gallium oxide crystals. Figure 1 Crystals of basically consistent quality.

[0080] Example 7

[0081] According to the molar ratio of gallium oxide, vanadium pentoxide and boron oxide of 0.4:1:0.30, 404.8 grams of gallium oxide, 982.3 grams of vanadium pentoxide and 112.8 grams of boron oxide raw materials were weighed respectively, and placed in a mixer to be fully mixed;

[0082] Pour the mixed raw materials into Φ100×80mm in batches. 3 Put the raw materials into a platinum crucible, put it into a muffle furnace, heat it to 980℃, keep it at this temperature for 2 hours to melt the raw materials, then cool it to room temperature, and repeat this process until all the raw materials are added into the platinum crucible;

[0083] Put the platinum crucible into a crystal growth furnace, raise the temperature to 1020°C, melt the above raw materials completely into a solution, and keep the temperature constant for 20 hours to obtain a uniform melt;

[0084] The temperature of the melt was gradually lowered, and the saturation point temperature of the melt was determined to be 950°C by the seed crystal trial method. The melt temperature was adjusted to 953°C (3°C higher than the saturation point temperature), and then the seed crystal for crystal growth was slowly immersed in the melt, and the seed crystal was rotated at a speed of 15 rpm. After the temperature was kept constant for 30 minutes, the melt temperature was adjusted to the saturation point temperature of 950°C.

[0085] The temperature was lowered at a rate of 2.0°C / day. After the gallium oxide crystals grew to the desired size, the rotation speed was adjusted to 5 rpm. The crystals were then pulled off the liquid surface and first cooled to 800°C at a rate of 25°C / hour, and then to room temperature at a rate of 50°C / hour to obtain gallium oxide crystals. Figure 1 Crystals of basically consistent quality.

[0086] Comparative Example 1

[0087] According to the molar ratio of gallium oxide, vanadium pentoxide and boron oxide of 0.8:1:0.40, 659.6 grams of gallium oxide, 800.5 grams of vanadium pentoxide and 122.5 grams of boron oxide raw materials were weighed respectively, and placed in a mixer to mix them thoroughly;

[0088] Pour the mixed raw materials into Φ100×80mm in batches. 3 Put the raw materials into a platinum crucible, put it into a muffle furnace, heat it to 1160℃, keep it at this temperature for 2 hours to melt the raw materials, then cool it to room temperature, and repeat this process until all the raw materials are added into the platinum crucible;

[0089] Put the platinum crucible into a crystal growth furnace, raise the temperature to 1215°C, melt the above raw materials completely into a solution, and keep the temperature constant for 25 hours to obtain a melt;

[0090] The temperature of the melt was gradually lowered, and the saturation point temperature of the melt was determined to be 1124°C by the seed crystal trial method. The melt temperature was adjusted to 1125°C (1°C higher than the saturation point temperature), and then the seed crystal for crystal growth was slowly immersed in the melt, and the seed crystal was rotated at a speed of 12 rpm. After the temperature was kept constant for 20 minutes, the melt temperature was adjusted to the saturation point temperature of 1124°C.

[0091] The temperature was lowered at a rate of 2.0°C / day. After the gallium oxide crystals grew to the desired size, the rotation speed was adjusted to 5 rpm. The crystals were then pulled off the liquid surface and first lowered to 800°C at a rate of 20°C / hour and then to room temperature at a rate of 50°C / hour to obtain gallium oxide crystals.

[0092] In this comparative example, due to the high boron oxide content, the melt viscosity is high and the melt uniformity is poor, resulting in inclusion defects in the grown gallium oxide crystals.

[0093] Comparative Example 2

[0094] According to the molar ratio of gallium oxide, vanadium pentoxide and boron oxide of 1.0:1:0.20, 749.6 grams of gallium oxide, 727.6 grams of vanadium pentoxide and 55.8 grams of boron oxide raw materials were weighed respectively, and placed in a mixer to be fully mixed;

[0095] Pour the mixed raw materials into Φ100×80mm in batches. 3 Put the raw materials into a platinum crucible, put it into a muffle furnace, heat it to 1250℃, keep it constant for 2 hours to melt the raw materials, then cool it to room temperature, and repeat this process until all the raw materials are added to the platinum crucible;

[0096] The platinum crucible was placed in a crystal growth furnace, heated to 1250°C and kept at this temperature for 30 hours. The raw material was still in a molten state and could not be melted into a solution, so subsequent crystal growth was impossible.

[0097] Comparative Example 3

[0098] According to the molar ratio of gallium oxide, vanadium pentoxide and boron oxide of 0.7:0:1.0, 787.0 grams of gallium oxide and 417.6 grams of boron oxide raw materials were weighed respectively, and placed in a mixer to be fully mixed;

[0099] Pour the mixed raw materials into Φ100×80mm in batches. 3 Put the raw materials into a platinum crucible, put it into a muffle furnace, heat it to 1030℃, keep it at this temperature for 2 hours to melt the raw materials, then cool it to room temperature, and repeat this process until all the raw materials are added into the platinum crucible;

[0100] Put the platinum crucible into a crystal growth furnace, raise the temperature to 1080°C, melt the above raw materials completely into a solution, and keep the temperature constant for 30 hours to obtain a melt;

[0101] The temperature of the melt was gradually lowered. Since the flux was only boron oxide and the melt viscosity was very high, the saturation point temperature of the melt could not be determined using the seed crystal trial method. The temperature was first lowered to 800°C at a rate of 25°C / hour, and then to room temperature at a rate of 50°C / hour. The product obtained in this comparative example was in a glassy state, and gallium oxide crystals could not be prepared.

[0102] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A flux for gallium oxide crystal growth, characterized in that: It includes vanadium pentoxide or a mixture of vanadium pentoxide and boron oxide.

2. The flux for gallium oxide crystal growth according to claim 1, characterized in that: The molar ratio of vanadium pentoxide to boron oxide is 1:(0-0.30).

3. The flux for gallium oxide crystal growth according to claim 2, characterized in that: The molar ratio of vanadium pentoxide to boron oxide is 1:(0.05-0.30).

4. The use of vanadium pentoxide as a flux in the growth of gallium oxide crystals, characterized in that: During crystal growth, the molar ratio of the gallium oxide raw material to vanadium pentoxide is (0.4-0.8):

1.

5. A method for growing gallium oxide crystals, characterized in that: The following steps are involved: Step 1: uniformly mixing a gallium oxide raw material and the flux according to any one of claims 1 to 3 to obtain a mixed raw material; Step 2: pour the mixed raw material obtained in step 1 into a crucible and heat it to melt, then test the saturation point temperature and introduce gallium oxide seed crystals; Step 3: Taking the saturation point temperature as the starting temperature, cooling down and rotating the gallium oxide seed crystal at the same time, growing the gallium oxide crystal on the gallium oxide seed crystal until the gallium oxide crystal on the gallium oxide seed crystal grows to a desired size, and the growth is terminated.

6. The method for growing gallium oxide crystals according to claim 5, characterized in that: The crucible is a platinum crucible.

7. The method for growing gallium oxide crystals according to claim 5, characterized in that: The temperature of heating and melting in step 2 is 1020-1250°C.

8. The method for growing gallium oxide crystals according to claim 5, characterized in that: The saturation point temperature of the melt in step 2 is 950-1150°C.

9. The method for growing gallium oxide crystals according to claim 5, characterized in that: The rotation speed of the gallium oxide seed crystal in step 3 is 5-15 rpm.

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