A method for growing a gallium oxide crystal

Abstract

The present application belongs to the technical field of gallium oxide crystal material, and particularly relates to a growth method of gallium oxide crystal. The present application takes gallium oxide, a mineralizer and water as raw materials, the mineralizer can promote the dissolution of gallium oxide in water under the condition of 150-1000 DEG C, the formed gallium oxide solution continuously circulates and flows in the hydrothermal reaction kettle under the action of natural convection, and contacts with the top gallium oxide seed crystal and carries out crystal growth. The growth method of the present application has low growth temperature, does not need to use iridium gold crucible, and has low cost. Meanwhile, the present application carries out crystal growth under the hydrothermal condition of 150-1000 DEG C, avoids the decomposition of gallium oxide into metallic gallium and gallium suboxide at 1800 DEG C, and improves the quality of gallium oxide crystal.

Description

Technical Field

[0001] This invention relates to the field of gallium oxide crystal material technology, and more particularly to a method for growing gallium oxide crystals. Background Technology

[0002] Gallium oxide is a semiconductor material, and its single crystal growth is mainly achieved using the melt method, which involves "heating and melting followed by cooling and crystallization." Conventional melt methods, including the mold-guided method and the Czochralski method, are all carried out at approximately 1800°C and require expensive iridium liners, which is detrimental to cost control and quality improvement. Summary of the Invention

[0003] In view of this, the object of the present invention is to provide a method for growing gallium oxide crystals. The growth method of the present invention can grow gallium oxide crystals at 150-1000°C, without the need for an iridium liner, and is low in cost.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides a method for growing gallium oxide crystals, comprising the following steps:

[0006] Gallium oxide is grown from the raw material under conditions of top gallium oxide seed crystal and hydrothermal conditions;

[0007] The raw materials include gallium oxide, mineralizing agent and water;

[0008] The mineralizing agent includes one or more of metal carbonates and metal hydroxides;

[0009] The hydrothermal temperature is 150–1000℃ and the pressure is 20–200 MPa.

[0010] Preferably, the metal carbonate includes one or more of alkali metal carbonates, alkaline earth metal carbonates, and Group III metal carbonates; the metal hydroxide includes one or more of alkali metal hydroxides, alkaline earth metal hydroxides, and Group III metal hydroxides.

[0011] Preferably, the alkali metal carbonate includes one or more of lithium carbonate, sodium carbonate, and potassium carbonate; the alkaline earth metal carbonate includes one or more of beryllium carbonate, magnesium carbonate, calcium carbonate, strontium carbonate, and barium carbonate; and the Group III metal carbonate includes one or more of aluminum carbonate, gallium carbonate, indium carbonate, and thallium carbonate. The alkali metal hydroxide includes one or more of lithium hydroxide, sodium hydroxide, and potassium hydroxide; the alkaline earth metal hydroxide includes one or more of beryllium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, and barium hydroxide; and the Group III metal hydroxide includes one or more of aluminum hydroxide, gallium hydroxide, indium hydroxide, and thallium hydroxide.

[0012] Preferably, the ratio of the mineralizing agent to water is 0.1 to 5 mol / L.

[0013] Preferably, the raw material further includes an oxidant, which includes hydrogen peroxide; the ratio of hydrogen peroxide to water is 0.1 to 5 mol / L.

[0014] Preferably, the ratio of gallium oxide to water is 0.01–5 g: 1 mL.

[0015] Preferably, the gallium oxide seed crystal is a plate-shaped gallium oxide crystal.

[0016] Preferably, the heating rate to the hydrothermal temperature is 2–15 °C / min.

[0017] Preferably, during the gallium oxide growth process, the temperature of the gallium oxide seed crystal region is 5 to 30°C lower than the temperature of the raw material region.

[0018] Preferably, the gallium oxide is grown in a hydrothermal reactor, and the lining of the hydrothermal reactor is made of titanium, titanium alloy, platinum or stainless steel.

[0019] The filling volume of the raw material in the hydrothermal reactor is 60-90% of the effective volume of the hydrothermal reactor.

[0020] This invention provides a method for growing gallium oxide crystals.

[0021] The growth method of this invention uses gallium oxide, a mineralizer, and water as raw materials. The mineralizer promotes the dissolution of gallium oxide in water at 150–1000°C. The resulting gallium oxide solution circulates continuously within a hydrothermal reactor under natural convection, contacting the top gallium oxide seed crystal for crystal growth. This method features a low growth temperature, eliminates the need for an iridium liner, and reduces costs. However, gallium oxide readily decomposes near 1800°C, producing metallic gallium and gallium suboxides. These decomposed materials corrode the iridium liner, and the resulting bubbles, corroded by the iridium liner, become incorporated into the crystal, significantly degrading the quality of the gallium oxide crystal. This invention, using hydrothermal conditions at 150–1000°C, prevents gallium oxide decomposition, minimizes corrosion of the liner, and avoids the incorporation of decomposed bubbles and corroded metal liner into the crystal, thus improving the quality of the gallium oxide crystal. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a hydrothermal reactor used for the gallium oxide crystal growth method provided by the present invention. Detailed Implementation

[0023] This invention provides a method for growing gallium oxide crystals, comprising the following steps:

[0024] Gallium oxide is grown from the raw material under conditions of top gallium oxide seed crystal and hydrothermal conditions;

[0025] The raw materials include gallium oxide, mineralizing agent and water;

[0026] The mineralizing agent includes one or more of metal carbonates and metal hydroxides;

[0027] The hydrothermal temperature is 150–1000℃ and the pressure is 20–200 MPa.

[0028] Unless otherwise specified, the raw materials used in this invention are preferably commercially available products.

[0029] In this invention, the raw materials include gallium oxide, a mineralizing agent, and water.

[0030] In this invention, the mineralizing agent comprises one or more of metal carbonates and metal hydroxides. Preferably, the metal carbonate comprises one or more of alkali metal carbonates, alkaline earth metal carbonates, and Group III metal carbonates. Preferably, the alkali metal carbonate comprises one or more of lithium carbonate, sodium carbonate, and potassium carbonate. Preferably, the alkaline earth metal carbonate comprises one or more of beryllium carbonate, magnesium carbonate, calcium carbonate, strontium carbonate, and barium carbonate. Preferably, the Group III metal carbonate comprises one or more of aluminum carbonate, gallium carbonate, indium carbonate, and thallium carbonate.

[0031] In this invention, the metal hydroxide preferably includes one or more of alkali metal hydroxides, alkaline earth metal hydroxides, and Group III metal hydroxides. In this invention, the alkali metal hydroxide preferably includes one or more of lithium hydroxide, sodium hydroxide, and potassium hydroxide. In this invention, the alkaline earth metal hydroxide preferably includes one or more of beryllium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, and barium hydroxide. In this invention, the Group III metal hydroxide preferably includes one or more of aluminum hydroxide, gallium hydroxide, indium hydroxide, and thallium hydroxide. In this invention, the mineralizing agent helps gallium oxide dissolve in water to facilitate gallium oxide transport and promote single crystal growth. When the mineralizing agent is lithium hydroxide (LiOH), it helps dissolve gallium oxide while also reducing the rate of single crystal growth and improving the quality of single crystal growth.

[0032] In this invention, the preferred ratio of the mineralizing agent to water is 0.1 to 5 mol / L, specifically preferably 0.1 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, 4.5 mol / L, or 5 mol / L.

[0033] In this invention, the preferred ratio of gallium oxide to water is 0.01–5 g:1 mL, more preferably 0.1–5 g:1 mL, and specifically preferably 0.01 g:1 mL, 0.05 g:1 mL, 0.1 g:1 mL, 0.2 g:1 mL, 0.3 g:1 mL, 0.4 g:1 mL, 0.5 g:1 mL, 0.6 g:1 mL, 0.7 g:1 mL, 0.8 g:1 mL, 0.9 g:1 mL, 1 g:1 mL, 1.5 g:1 mL, 2 g:1 mL, 2.5 g:1 mL, 3 g:1 mL, 3.5 g:1 mL, 4 g:1 mL, 4.5 g:1 mL, or 5 g:1 mL.

[0034] In this invention, the raw materials preferably further include an oxidant, which preferably includes hydrogen peroxide; the ratio of hydrogen peroxide to water is preferably 0.1–5 mol / L, more preferably 1–5 mol / L, and specifically preferably 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, 4.5 mol / L, or 5 mol / L. In this invention, the oxidant can enhance the effect of the mineralizing agent, increase the solubility of gallium oxide, and promote the transport of gallium oxide.

[0035] In this invention, the gallium oxide seed crystal is preferably a plate-shaped gallium oxide crystal. Preferably, there is at least one gallium oxide seed crystal; when there are two or more, the seed crystals are preferably placed sequentially along a vertical direction. In this invention, the gallium oxide seed crystal serves as the initial growth site for the crystal, constructing the basic structure for crystal growth. The main exposed surface of the plate-shaped gallium oxide crystal is the target crystal plane, which improves the growth efficiency for large-size target crystal planes. The use of multiple gallium oxide seed crystals further enhances growth efficiency.

[0036] In this invention, the hydrothermal temperature is 150–1000℃, preferably 200–800℃, and specifically preferably 150℃, 200℃, 250℃, 300℃, 350℃, 400℃, 450℃, 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, 900℃, 950℃, or 1000℃; the heating rate to the hydrothermal temperature is preferably 2–15℃ / min, more preferably 5–10℃ / min, and specifically preferably 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, or 7℃ / min. The hydrothermal rate is 8℃ / min, 9℃ / min, 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min, or 15℃ / min; the pressure is 20–200 MPa, preferably 50–150 MPa, specifically preferably 20 MPa, 30 MPa, 40 MPa, 50 MPa, 60 MPa, 70 MPa, 80 MPa, 90 MPa, 100 MPa, 110 MPa, 120 MPa, 130 MPa, 140 MPa, 150 MPa, 160 MPa, 170 MPa, 180 MPa, 190 MPa, or 200 MPa. In this invention, the hydrothermal temperature can adjust the solubility and dissolution temperature coefficient of gallium oxide in water to control the growth rate.

[0037] In this invention, during the gallium oxide growth process, the temperature of the gallium oxide seed crystal region is preferably 5-30°C lower than the temperature of the raw material region, more preferably 10-20°C lower, and specifically preferably 5°C, 10°C, 15°C, 20°C, 25°C, or 30°C. In this invention, reducing the temperature difference between the gallium oxide seed crystal region and the raw material region can reduce convection and decrease the crystal growth rate; increasing the temperature difference can enhance convection and accelerate the crystal growth rate.

[0038] In this invention, the gallium oxide growth is preferably carried out in a hydrothermal reactor. The filling volume of the raw material in the hydrothermal reactor is preferably 60% to 90% of the effective volume of the reactor, specifically 60%, 65%, 70%, 75%, 80%, 85%, or 90%. Controlling the filling volume of the raw material in the hydrothermal reactor to 60% to 90% of the effective volume facilitates natural convection of the gallium oxide solution formed by the raw material, allowing it to circulate within the reactor and contact the gallium oxide seed crystal, thus achieving gallium oxide growth.

[0039] In this invention, a schematic diagram of the hydrothermal reactor is shown below. Figure 1As shown. In this invention, the lining material of the hydrothermal reactor is preferably titanium, titanium alloy, platinum, or stainless steel, more preferably platinum; the lining of the hydrothermal reactor can prevent the reactants inside the reactor cavity from corroding the reactor cavity. In this invention, the hydrothermal reactor preferably includes a reactor cavity, and the raw materials are placed inside the reactor cavity; the reactor cavity can withstand a high-pressure environment. In this invention, a baffle plate is provided inside the reactor cavity, and the function of the baffle plate is to control the convection in the reactor cavity and improve the growth conditions. In this invention, the hydrothermal reactor preferably includes sealing bolts, and the function of the sealing bolts is to seal the reactor cavity so that it can maintain a high-pressure state. In this invention, the exterior of the reactor cavity preferably also includes a heating system, and the heating system can realize the heating of the reactor cavity.

[0040] This invention does not impose a specific limitation on the gallium oxide growth time; those skilled in the art can control it according to the required size of the gallium oxide crystal. In a specific embodiment of this invention, the gallium oxide growth time is preferably 30 days.

[0041] After gallium oxide growth, the present invention preferably further includes: stopping heating and cooling down, releasing pressure and removing the crystal after it has cooled to room temperature, and cleaning it to obtain gallium oxide crystal.

[0042] In this invention, gallium oxide is dissolved in water under hydrothermal conditions by a mineralizing agent to form a gallium oxide solution. The gallium oxide solution circulates continuously in the hydrothermal reactor under natural convection conditions and comes into contact with the gallium oxide seed crystal at the top to grow crystals.

[0043] The following detailed description of the gallium oxide crystal growth method provided by the present invention, in conjunction with embodiments, should not be construed as limiting the scope of protection of the present invention.

[0044] Example 1

[0045] Gallium oxide, potassium hydroxide, lithium hydroxide, hydrogen peroxide, and water are mixed to form a raw material, which is then placed in... Figure 1In a hydrothermal reactor, the ratio of gallium oxide to water is 0.1 g: 1 mL, the ratio of potassium hydroxide to water is 2 mol / L, the ratio of lithium hydroxide to water is 1 mol / L, and the ratio of hydrogen peroxide to water is 1 mol / L. The filling volume of the raw materials (including gallium oxide, potassium hydroxide, lithium hydroxide, hydrogen peroxide, and water) in the hydrothermal reactor is 80% of the effective volume of the reactor. Two gallium oxide seed crystals are placed vertically on top. The hydrothermal reactor is then sealed with sealing bolts, and the temperature is raised to 800°C at a rate of 5°C / min, with the pressure controlled at 50 MPa. After reaching 800°C, the temperature of the gallium oxide seed crystal area is controlled to be 25°C lower than the temperature of the raw material area. Gallium oxide growth is carried out for 30 days. Heating is stopped and the temperature is lowered until it reaches room temperature. The pressure is released and the crystal is removed. After cleaning, gallium oxide crystals are obtained.

[0046] Example 2

[0047] Gallium oxide, gallium hydroxide, lithium hydroxide, and water are mixed to form a raw material, which is then placed in... Figure 1 In a hydrothermal reactor, the ratio of gallium oxide to water is 0.3 g: 1 mL, the ratio of gallium hydroxide to water is 0.5 mol / L, and the ratio of lithium hydroxide to water is 1 mol / L. The filling volume of the raw materials (including gallium oxide, gallium hydroxide, lithium hydroxide, and water) in the hydrothermal reactor is 75% of the effective volume of the reactor. Two gallium oxide seed crystals are placed vertically on top. The hydrothermal reactor is then sealed with sealing bolts, and the temperature is raised to 600°C at a rate of 5°C / min, while the pressure is controlled at 100 MPa. After reaching 600°C, the temperature of the gallium oxide seed crystal area is controlled to be 20°C lower than that of the raw material area. Gallium oxide growth is carried out for 30 days. Heating is stopped and the temperature is lowered until it reaches room temperature. The pressure is released and the crystals are removed. After cleaning, gallium oxide crystals are obtained.

[0048] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for growing gallium oxide crystal, characterized in that, Includes the following steps: Gallium oxide is grown from the raw material under conditions of top gallium oxide seed crystal and hydrothermal conditions; The raw materials include gallium oxide, mineralizing agent and water; The mineralizing agent includes one or more of metal carbonates and metal hydroxides; The hydrothermal temperature is 150–1000℃ and the pressure is 20–200 MPa.

2. The growth method according to claim 1, characterized in that, The metal carbonate includes one or more of alkali metal carbonates, alkaline earth metal carbonates, and Group III metal carbonates; the metal hydroxide includes one or more of alkali metal hydroxides, alkaline earth metal hydroxides, and Group III metal hydroxides.

3. The growth method according to claim 2, characterized in that, The alkali metal carbonates include one or more of lithium carbonate, sodium carbonate, and potassium carbonate; the alkaline earth metal carbonates include one or more of beryllium carbonate, magnesium carbonate, calcium carbonate, strontium carbonate, and barium carbonate; and the Group III metal carbonates include one or more of aluminum carbonate, gallium carbonate, indium carbonate, and thallium carbonate. The alkali metal hydroxides include one or more of lithium hydroxide, sodium hydroxide, and potassium hydroxide; the alkaline earth metal hydroxides include one or more of beryllium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, and barium hydroxide; and the Group III metal hydroxides include one or more of aluminum hydroxide, gallium hydroxide, indium hydroxide, and thallium hydroxide.

4. The growth method according to any one of claims 1 to 3, characterized in that, The ratio of the mineralizing agent to water is 0.1–5 mol / L.

5. The growth method according to claim 1, characterized in that, The raw materials also include an oxidant, which includes hydrogen peroxide; the ratio of hydrogen peroxide to water is 0.1 to 5 mol / L.

6. The growth method according to claim 1, characterized in that, The ratio of gallium oxide to water is 0.01–5 g: 1 mL.

7. The growth method according to claim 1, characterized in that, The gallium oxide seed crystal is a plate-shaped gallium oxide crystal.

8. The growth method according to claim 1, characterized in that, The heating rate to the hydrothermal temperature is 2–15 °C / min.

9. The growth method according to claim 1, characterized in that, During the gallium oxide growth process, the temperature of the gallium oxide seed crystal region is 5 to 30°C lower than the temperature of the raw material region.

10. The growth method according to claim 1, characterized in that, The gallium oxide is grown in a hydrothermal reactor, and the lining of the hydrothermal reactor is made of titanium, titanium alloy, platinum or stainless steel. The filling volume of the raw material in the hydrothermal reactor is 60-90% of the effective volume of the hydrothermal reactor.

Images