Apparatus and method for growing crystals in supercritical fluid state

Abstract

The application discloses a device and method for growing crystals in a supercritical fluid state, and belongs to the field of semiconductor material preparation. The device comprises a furnace body, a high-temperature chamber and a growth chamber arranged in the furnace body, and a reaction gas channel penetrating through the high-temperature chamber and the growth chamber. A single-element melt is placed in a crucible in the high-temperature chamber, and a supercritical fluid is injected into the melt through the reaction gas channel. At high temperature, the melt atoms are mixed into the high-temperature supercritical fluid, and then the supercritical fluid enters the growth chamber and meets the seed crystal with a lower temperature, and the compound crystal starts to grow. The device and method provided by the application use pure element A instead of polycrystal material, and the reaction gas plays a role in carrying the pure element A and synthesizing the crystal with the pure element A in the growth chamber, thereby improving the efficiency. The reaction gas is injected from the outside during the reaction, and the speed and quantity are controllable, thereby accelerating the crystal growth.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor material preparation, specifically an apparatus and method for growing crystals in a supercritical fluid state. Background Technology

[0002] Compound semiconductors are fundamental to the fabrication of semiconductor devices and play a crucial role in the information field. However, many compound semiconductors are difficult to fabricate. For example, gallium oxide and silicon carbide are difficult to fabricate directly using melt methods and require growth techniques such as physical vapor deposition, which are costly and inefficient. Indium phosphide and gallium phosphide require fabrication under high pressure, making it difficult to grow large enough crystals with low yields.

[0003] Furthermore, taking the growth of indium phosphide crystals as an example, the current technique involves first generating the compound and then growing the single crystal. Although isotopic growth can be achieved, problems such as long growth cycles still exist.

[0004] As temperature and pressure change, some substances will exhibit three phases: solid, liquid, and gas. The temperature and pressure at which these three phases transform into each other are called the triple point. In addition to the triple point, stable substances with relatively small molecular weights also have a critical point, which is composed of the critical temperature, critical pressure, and critical density. When a substance in gas-liquid equilibrium is heated and pressurized, thermal expansion causes the liquid density to decrease, and the increase in pressure causes the interface between the gas and liquid phases to disappear, resulting in a homogeneous system. This point is called the critical point.

[0005] Fluids with temperatures and pressures above their critical points are called supercritical fluids. Supercritical fluids exist in a state where gas and liquid are indistinguishable, lacking a clear gas-liquid interface; they are neither liquid nor gas. When the temperature and pressure of water rise above the critical point (t=374.3 ℃, p=22.05 MPa), it enters a new fluid state—supercritical—that is distinct from both gaseous, liquid, and solid states. Water in this state is called supercritical water.

[0006] Because supercritical fluids are in a supercritical state, they are highly sensitive to changes in temperature and pressure and have very unique physical properties. They have low viscosity, high density, and good flow, mass transfer, heat transfer, and dissolution properties. Therefore, they are widely used in energy conservation, natural product extraction, polymerization reactions, production of ultrafine powders and fibers, spraying and coatings, catalytic processes, and supercritical chromatography.

[0007] In the process of preparing gallium nitride single crystals, there are methods that utilize materials in a supercritical state.

[0008] Gallium nitride (GaN) single crystals can be grown using methods such as hydride vapor phase epitaxy, high-pressure nitrogen solution method, hydrothermal method, ammonothermal method, and Na flux method. Both hydrothermal and ammonothermal methods are solvothermal processes, referring to solvent crystallization methods performed in supercritical, subcritical, or both states. When water is used as the solvent, it is called the hydrothermal method; when ammonia is used, it is called the ammonothermal method. As disclosed in Chinese patent application CN112048771 A, the process involves placing GaN polycrystalline material, a mineralizer, and a seed crystal in separate cavities. Ammonia gas is then introduced into these cavities, which are sealed and heated individually. The temperature difference between the cavities causes the ammonia gas to flow between them. The ammonia gas acquires the polycrystalline material and carries it to the cavity containing the seed crystal, where a single crystal grows.

[0009] No similar methods have been observed in the growth processes of indium phosphide, silicon carbide, and gallium oxide. Furthermore, in the aforementioned processes, the raw material is polycrystalline, and ammonia gas merely carries the reactants without participating in the reaction; the movement speed of the ammonia gas depends on the temperature difference within the cavity and cannot be controlled externally. Summary of the Invention

[0010] The purpose of this invention is to provide an apparatus and a method for growing semiconductor crystals using the apparatus, in order to solve the above-mentioned problems.

[0011] To achieve the purpose of the invention, the present invention adopts the following technical solution.

[0012] An apparatus for growing crystals in a supercritical fluid state includes a sealed furnace body, a balancing gas valve connected to a pipeline, and a vacuum valve connected to a pipeline. The key feature is that an air inlet is located at the top of the furnace body, and an injection pipe is installed within the air inlet. The lower end of the injection pipe is aligned with the center of a crucible inside a high-temperature chamber. The high-temperature chamber is located above the growth chamber, and a fluid channel connects the high-temperature chamber and the growth chamber. A growth substrate is installed inside the growth chamber. An air outlet is located at the bottom of the furnace body, and a discharge pipe is installed within the air outlet. The upper end of the discharge pipe enters the growth chamber, and a gas passage valve and a vent valve are installed on the discharge pipe.

[0013] A main heating element is installed around the high-temperature greenhouse, a first auxiliary heating element is installed around the fluid channel, and a second auxiliary heating element is installed around the growth chamber.

[0014] A first thermocouple, a second thermocouple, and a third thermocouple are respectively installed on the outside of the high-temperature room, the outside of the fluid channel, and the outside of the growth room.

[0015] Furthermore, the injection pipe is connected to the gas source box via a first one-way valve, and the discharge pipe is connected to a second one-way valve via a gas pressurization pump. The second one-way valve is connected to the injection pipe, and the gas pressurization pump is connected to the gas source box.

[0016] Based on the above-mentioned apparatus, the present invention also proposes a method for growing crystals under supercritical fluid conditions, comprising the following steps: Step 1: Place pure element A into the crucible and fix the sheet-like seed crystal onto the growth substrate; Step 2: Assemble the apparatus for growing crystals under supercritical fluid conditions; Step 3: Open the vacuum valve to evacuate the furnace body, and open the vent valve to evacuate the high-temperature chamber and growth chamber to a vacuum level of 10⁻⁵ Pa to 10 Pa; then close the vacuum valve and vent valve. Step 4: Heat the high-temperature chamber to T1 using the main heating element; heat the constant temperature transfer tube (2-4) to T1 using the first auxiliary heating element; heat the growth chamber to T2 using the second auxiliary heating element. T1 is greater than the melting point of pure element A, and T2 is the suitable growth temperature of the compound, so T1>T2; Step 5: Raise the injection pipe above pure element A, close the gas valve, open the balance gas valve to fill the furnace with inert gas, so that the internal pressure of the furnace reaches P1. At the same time, fill the high-temperature chamber with reaction gas through the injection pipe to keep the pressure inside and outside the high-temperature chamber consistent. Once the temperature and pressure in the high-temperature chamber reach T1 and P1, the introduction of inert gas is stopped, and the temperature is maintained. P1 and T1 are greater than or equal to the critical conditions for the reacting gas; Step 6: Insert the injection tube into the melt of pure element A, and inject the reaction gas into the melt of pure element A through the injection tube; open the gas valve to allow the gas in the growth chamber to flow out; maintain the temperature T2 in the growth chamber. The reactant gas is in a supercritical fluid state and is rich in pure element A. When it encounters the plate-like seed crystals on the growth substrate, it begins to grow and form compound crystals. Step 7: After growth is complete, stop injecting the reaction gas, raise the injection pipe, open the vent valve, close the gas valve, and gradually reduce the pressure in the high-temperature chamber, growth chamber, and furnace to the ambient pressure outside the furnace; fill the high-temperature chamber with inert gas until the reaction gas is exhausted; stop heating the main heating body, the first auxiliary heating body, and the second auxiliary heating body; after reaching room temperature, cut and dismantle the equipment and remove the crystal. The pure element A reacts with the reactive gas to generate a semiconductor material.

[0017] This invention injects a supercritical fluid-state reaction gas into a melt of pure element A. Utilizing the characteristics of supercritical fluids, the reaction gas carries abundant pure element A after overflowing the melt. Upon entering the growth chamber, it encounters a seed crystal under low-temperature conditions, thus growing and forming a compound crystal.

[0018] Beneficial effects: The apparatus and method proposed in this invention can grow some crystals that are difficult to grow by melt method; compared with traditional physical vapor phase method and chemical vapor phase method, crystals can be grown rapidly; this invention does not use mineralizers, and the raw material does not use polycrystalline material but pure element A. The reaction gas plays the role of carrying pure element A and synthesizes crystals with pure element A in the growth chamber, which improves efficiency; the reaction gas is injected from the outside during the reaction process, and the speed and quantity are controllable, which accelerates crystal growth. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the device of the present invention; Figure 2 This is a schematic diagram of the structure of the high-temperature greenhouse; Figure 3 This is a schematic diagram of the growth chamber. Figure 4 This is a schematic diagram of the gas pipeline outside the furnace body; Figure 5 This is another schematic diagram of the gas pipeline outside the furnace body.

[0020] Wherein, 1: Furnace body; 2: High-temperature chamber; 2-1: Air inlet pipe; 2-2: High-temperature chamber cover; 2-3: High-temperature main chamber; 2-4: Transmission thermostatic pipe; 3: Air inlet; 4: Main heating element; 5: Crucible; 5-1: Crucible support; 5-2: Crucible support vent; 6: Pure element A melt; 7: Balance valve; 8: Vacuum valve; 9: First auxiliary heating element; 10-1: First thermocouple; 10-2: Second thermocouple; 10-3: Third thermocouple; 11: Growth chamber; 11-1: Growth chamber cover; 11-2: Interface; 11-3: Growth main chamber; 11-4: Transfer outlet; 12: Growth substrate; 12-1: Growth substrate support; 12-2: Vent hole of growth substrate support; 13: Plate seed crystal; 14: Second auxiliary heating element; 15: Gas outlet; 16: Discharge pipe; 17: Injection pipe; 17-1: Drive motor; 18: Bubble; 19: Gas valve; 20: Vent valve; 21: Gas pressurization pump; 22-1: First check valve; 22-2: Second check valve; 23: Gas source box; 24: Condensation chamber. Figure 4 , Figure 5 The line with an arrow indicates the direction of gas flow. Detailed Implementation

[0021] An apparatus for growing crystals in a supercritical fluid state, see [link / reference] Figure 1 The main body of the device includes a closed furnace body 1, a balance gas valve 7 connecting the pipeline, and a vacuum valve 8 connecting the pipeline. Inside the furnace body 1 are a high-temperature chamber 2, a growth chamber 11, and a reaction gas channel that runs through the high-temperature chamber 2 and the growth chamber 11.

[0022] The furnace body 1 has an air inlet 3 at the top and an injection pipe 17 in the air inlet 3. The lower end of the injection pipe 17 is aligned with the center of the crucible 5 inside the high-temperature chamber 2. The high-temperature chamber 2 is located above the growth chamber 11. There is a fluid channel connecting the high-temperature chamber 2 and the growth chamber 11. The growth chamber 11 has a growth substrate 12 inside. The furnace body 1 has an air outlet 15 at the bottom and a discharge pipe 16 inside the air outlet 15. The upper end of the discharge pipe 16 enters the growth chamber 11. The discharge pipe 16 is equipped with a gas passage valve 19 and a relief valve 20.

[0023] See Figure 2 The high-temperature chamber 2 includes a high-temperature main chamber 2-3, a high-temperature chamber cover 2-2, an air inlet pipe 2-1 provided in the middle of the high-temperature chamber cover 2-2 for the injection pipe 17 to pass through, and a transmission constant temperature pipe 2-4, wherein the transmission constant temperature pipe 2-4 is a fluid channel.

[0024] The injection tube 17, the transmission thermostatic tube 2-4, and the discharge tube 16 form the reaction gas channel.

[0025] A main heating element 4 is installed around the high-temperature chamber 2, a first auxiliary heating element 9 is installed around the fluid channel, i.e., the constant temperature transmission pipe 2-4, and a second auxiliary heating element 14 is installed around the growth chamber 11.

[0026] A first thermocouple 10-1, a second thermocouple 10-2, and a third thermocouple 10-3 are respectively installed on the outside of the high-temperature chamber 2, the outside of the fluid channel (i.e., the constant temperature transmission pipe 2-4), and the outside of the growth chamber 11.

[0027] See Figure 3 The growth chamber 11 includes a growth main chamber 11-3, a growth chamber cover 11-1, an interface 11-2 for the fluid channel located in the middle of the growth chamber cover 11-1, and a transmission outlet 11-4 for the supply and discharge pipe 16 located in the middle of the bottom surface of the growth main chamber 11-3.

[0028] The present invention also proposes an embodiment of a gas supply device located outside the furnace body 1.

[0029] See Figure 4 The gas supply device includes a gas supply box 23 and a connection structure: the injection pipe 17 is connected to the gas supply box 23 through a first one-way valve 22-1, the discharge pipe 16 is connected to a second one-way valve 22-2 through a gas pressurizing pump 21, the second one-way valve 22-2 is connected to the injection pipe 17, and the gas pressurizing pump 21 is connected to the gas supply box 23.

[0030] To accommodate different combinations of pure element A and reaction gases, the present invention also proposes the following embodiment: a condensation chamber 24 is provided between the discharge pipe 16 and the gas pressurization pump 21.

[0031] Based on the apparatus described in the preferred embodiments above, the present invention also proposes a method for growing crystals in a supercritical fluid state, comprising the following steps.

[0032] Step 1: Place pure element A into crucible 5 and fix the sheet seed crystal 13 onto growth substrate 12; place reaction gas in gas source box 23, the original state of the reaction gas being gaseous, liquid or solid.

[0033] Step 2: Assemble the apparatus for growing crystals under supercritical fluid conditions: Place the crucible 5 onto the crucible support 5-1 in the high-temperature main chamber 2-3, and weld the high-temperature chamber cover 2-2 to the high-temperature main chamber 2-3; Place the seed crystal 13 and the growth substrate 12 onto the growth substrate support 12-1 in the growth main chamber 11-3, and weld the growth chamber cover 11-1 to the growth main chamber 11-3. Align the transmission thermostat tube 2-4 with the interface 11-2, and weld the transmission thermostat tube 2-4 to the growth chamber cover 11-1, so that the growth chamber 11 and the high temperature chamber 2 form a whole; The air inlet pipe 2-1 is connected to the air inlet 3, the transmission outlet 11-4 is connected to the air outlet 15, and the injection pipe 17 and the discharge pipe 16 are assembled. Assemble furnace body 1, install first thermocouple 10-1, second thermocouple 10-2 and third thermocouple 10-3; connect gas supply device.

[0034] Step 3: Open vacuum valve 8 to evacuate furnace body 1; open relief valve 20 to evacuate high temperature chamber 2 and growth chamber 11 to evacuate to 10⁻⁵ Pa - 10 Pa; close vacuum valve 8 and relief valve 20.

[0035] During the vacuuming process, the gas valve 19 is in the open state and the gas source box 23 has no output; after the vacuuming is completed, the interior of the furnace body 1, the high temperature chamber 2, the growth chamber 11, and the connecting structure in the gas source supply device are all in a vacuum state.

[0036] Step 4: Heat the high-temperature chamber 2 to T1 through the main heating element 4, and heat the transmission thermostatic tube 2-4 to T1 through the first auxiliary heating element 9; heat the growth chamber 11 to T2 through the second auxiliary heating element 14; T1 is greater than the melting point of pure element A, T2 is the suitable growth temperature of the compound, and T1>T2.

[0037] At this point, pure element A in crucible 5 melts into pure element A melt 6.

[0038] The choice of temperature depends on the pure element A, the reaction gas, and the final crystal formed: if the pure element A is indium, the reaction gas is phosphorus, and the final crystal formed is indium phosphide, then T1 must be greater than 1062℃, and the range of T2 is 900℃-1062℃.

[0039] Step 5: Using the drive motor 17-1, lift the injection pipe 17 above the pure element A, i.e., the pure element A melt 6. Close the gas valve 19 and open the balance gas valve 7 to fill the furnace body 1 with inert gas, so that the internal pressure of the furnace body 1 reaches P1. At the same time, fill the high-temperature chamber 2 with reaction gas through the injection pipe 17, so that the internal pressure of the high-temperature chamber 2 also reaches P1, keeping the internal and external pressures of the high-temperature chamber 2 consistent.

[0040] Once the temperature and pressure of the high-temperature chamber 2 reach T1 and P1, the introduction of inert gas is stopped, and the temperature is maintained; P1 and T1 are greater than or equal to the critical conditions of the reacting gas.

[0041] P1 and T1 both depend on pure element A, the reaction gas, and the final crystal: if pure element A is indium, the reaction gas is phosphorus, and the final crystal is indium phosphide, then P1 is greater than 15 MPa and T1 is greater than 1062 °C.

[0042] The critical temperature of phosphorus is 721℃, and the critical pressure (MPa) is 8.32. The high-temperature chamber 2 is connected to the growth chamber 11 at the same pressure, and phosphorus is in a supercritical fluid state in both the high-temperature chamber 2 and the growth chamber 11.

[0043] Step 6: Insert the injection pipe 17 into the pure element A melt 6 and inject the reaction gas into the pure element A melt through the injection pipe 17; open the gas valve 19 to allow the gas in the growth chamber 11 to flow out; maintain the temperature T2 in the growth chamber 11.

[0044] The reactant gas is in a supercritical fluid state and is rich in pure element A. When it encounters the sheet-like seed crystals 13 on the growth substrate 12, it begins to grow and form compound crystals.

[0045] Gas source box 23 provides the reaction gas. When the reaction gas comes out of gas source box 23, it is not required to be in a supercritical fluid state. When the reaction gas is injected from injection pipe 17, due to the environment formed by P1 and T1 in high temperature chamber 2, which is greater than or equal to the critical condition for the reaction gas to be in a supercritical fluid state, the reaction gas is in a supercritical fluid state under this condition. After entering the pure element A melt 6, it absorbs pure element A and then carries pure element A out in the form of bubbles 18.

[0046] The reaction gas carrying pure element A enters the growth chamber 11 through the constant temperature transmission tube 2-4. The temperature and pressure of the constant temperature transmission tube 2-4 are the same as those of the high temperature chamber 2. No physical or chemical changes occur when the reaction gas carrying pure element A passes through it.

[0047] A crucible support vent 5-2 is provided on the crucible support 5-1 to accelerate the flow of gas.

[0048] Upon entering growth chamber 11, the temperature inside chamber 11 is T2, where T1 > T2. Because the supercritical fluid is in a supercritical state, it is highly sensitive to changes in temperature and pressure. The pressure in the high-temperature chamber 2 and growth chamber 11 is the same, but their temperatures differ; the temperature inside growth chamber 11 is lower than that in high-temperature chamber 2. When it comes into contact with the plate-like seed crystal 13 or the grown compound crystal, it releases pure element A and reacts with it to form a compound crystal.

[0049] The reaction gas entering the growth chamber 11 is discharged from the exhaust pipe 16.

[0050] A vent hole 12-2 is provided on the growth substrate support 12-1 to accelerate the flow of gas.

[0051] Repeat step 6, and the compound crystal continues to grow until the pure element A in crucible 5 is basically consumed.

[0052] Step 7: After growth is complete, stop injecting the reaction gas, raise the injection pipe 17, open the vent valve 20, close the gas valve 19, open the vacuum valve 8, and at the same time gradually reduce the pressure in the high-temperature chamber 2, growth chamber 11 and furnace body 1 to the ambient pressure outside the furnace body; fill the high-temperature chamber 2 with inert gas until the reaction gas is exhausted; stop heating the main heating body 4, the first auxiliary heating body 9 and the second auxiliary heating body 14, and after the room temperature is reached, cut and dismantle the equipment and take out the crystal.

[0053] This invention requires a specific combination of pure element A and a reactive gas, provided that the reaction between pure element A and the reactive gas can generate a semiconductor material. The advantage is that the reactive gas in the critical state simultaneously carries pure element A and participates in the reaction, directly generating a single crystal of the compound.

[0054] If element A is indium, the reacting gas is phosphorus, and indium phosphide is ultimately produced; if element A is gallium, the reacting gas is oxygen, and gallium oxide is ultimately produced; if element A is silicon, the reacting gas is methane, and silicon carbide is ultimately produced. This invention is not limited to using the above combinations.

[0055] After selecting the appropriate combination, the values ​​and ranges of T1, T2, and P1 are determined based on the critical conditions of the reactant gases and the suitable temperature for crystal growth.

[0056] The reaction gas discharged from growth chamber 11 also carries some pure element A, which can be recovered and reused.

[0057] The present invention also proposes embodiments for the reuse of reactive gases.

[0058] See Figure 4The pressurized gas inlet of the gas pressurization pump 21 is connected to the discharge pipe 16, the pressurized gas outlet is connected to the injection pipe 17, and the drive gas inlet is connected to the gas source box 23. Due to the presence of the first one-way valve 22-1 and the second one-way valve 22-2, the gas can only move in the direction of the arrow.

[0059] The gas source box 23 maintains the gas output pressure P1. Since the reaction gas is consumed in the growth chamber 11, the reaction gas will be continuously injected. When the reaction gas flow rate decreases or stops, the gas pressurization pump 21 is turned on for a period of time to deliver the reaction gas discharged from the discharge pipe 16 to the injection pipe 17 and enter the high-temperature chamber 2.

[0060] The reaction gas can be recycled by intermittently turning on the gas pressurization pump 21.

[0061] To maintain the reaction gas discharged from the discharge pipe 16 in a supercritical fluid state, heating and insulation devices can be installed on the pipeline to maintain the gas temperature.

[0062] In the above embodiments, the reaction gas and the pure element A carried therein are recycled simultaneously.

[0063] The present invention also proposes an embodiment, see below. Figure 5 A condenser 24 is set between the discharge pipe 16 and the gas pressurization pump 21. The reaction gas is cooled in the condenser 24, and the pure element A it carries is discarded. Only the reaction gas is delivered to the injection pipe 17 and enters the high temperature chamber 2.

Claims

1. An apparatus for growing crystals in a supercritical fluid state, the apparatus comprising a sealed furnace body (1), a balancing gas valve (7), and a vacuum valve (8), characterized in that, The furnace body (1) has an air inlet (3) at the top and an injection pipe (17) in the air inlet (3). The lower end of the injection pipe (17) is aligned with the center of the crucible (5) inside the high-temperature chamber (2). The high-temperature chamber (2) is located above the growth chamber (11). There is a fluid channel connecting the high-temperature chamber (2) and the growth chamber (11). A growth substrate (12) is installed inside the growth chamber (11). The furnace body (1) has an air outlet (15) at the bottom and a discharge pipe (16) inside the air outlet (15). 6) The upper end enters the growth chamber (11), and the exhaust pipe (16) is equipped with a gas valve (19) and a vent valve (20); the high-temperature chamber (2) is equipped with a main heating element (4), the fluid channel is equipped with a first auxiliary heating element (9), and the growth chamber (11) is equipped with a second auxiliary heating element (14); the high-temperature chamber (2), the fluid channel, and the growth chamber (11) are respectively equipped with a first thermocouple (10-1), a second thermocouple (10-2), and a third thermocouple (10-3); Heating and heat preservation devices are provided on the discharge pipe (16); The crucible (5) contains pure element A; the pure element A is used to react with the reaction gas to generate semiconductor material.

2. The apparatus according to claim 1, characterized in that, The high-temperature chamber (2) includes a high-temperature main chamber (2-3), a high-temperature chamber cover (2-2), an air inlet pipe (2-1) provided in the middle of the high-temperature chamber cover (2-2) for the injection pipe (17) to pass through, and a transmission constant temperature pipe (2-4), wherein the transmission constant temperature pipe (2-4) is a fluid channel.

3. The apparatus according to claim 1, characterized in that, The growth chamber (11) includes a growth main chamber (11-3), a growth chamber cover (11-1), an interface (11-2) in the middle of the growth chamber cover (11-1) that communicates with the fluid channel, and a transmission outlet (11-4) through which the supply and discharge pipe (16) passes in the middle of the bottom surface of the growth main chamber (11-3).

4. The apparatus according to claim 1, characterized in that, The injection pipe (17) is connected to the gas source box (23) through the first one-way valve (22-1), the discharge pipe (16) is connected to the second one-way valve (22-2) through the gas pressurizing pump (21), the second one-way valve (22-2) is connected to the injection pipe (17), and the gas pressurizing pump (21) is connected to the gas source box (23).

5. The apparatus according to claim 4, characterized in that, A condenser (24) is provided between the discharge pipe (16) and the gas pressurization pump (21).

6. A method for growing crystals under supercritical fluid conditions, characterized in that, The process is achieved using the apparatus for growing crystals in a supercritical fluid state as described in any one of claims 1-5, and includes the following steps: Step 1: Place pure element A into crucible (5) and fix the sheet seed crystal (13) onto the growth substrate (12). Step 2: Assemble the apparatus for growing crystals under supercritical fluid conditions; Step 3: Open the vacuum valve (8) to evacuate the furnace body (1), and open the vent valve (20) to evacuate the high-temperature chamber (2) and the growth chamber (11) until the vacuum reaches 10. -5 Pa-10Pa; Close the vacuum valve (8) and the relief valve (20); Step 4: Heat the high-temperature chamber (2) to T1 through the main heating element (4), heat the transmission thermostat tube (2-4) to T1 through the first auxiliary heating element (9), and heat the growth chamber (11) to T2 through the second auxiliary heating element (14); T1 is greater than the melting point of pure element A, and T2 is the suitable growth temperature of the compound, so T1>T2; Step 5: Raise the injection pipe (17) above pure element A, close the gas valve (19), open the balance gas valve (7) to fill the furnace body (1) with inert gas, so that the internal pressure of the furnace body (1) reaches P1. At the same time, fill the high-temperature chamber (2) with reaction gas through the injection pipe (17) to keep the pressure inside and outside the high-temperature chamber (2) consistent. After the temperature and pressure of the high-temperature chamber (2) reach T1 and P1, the inert gas filling is stopped and the temperature is maintained; P1 and T1 are greater than or equal to the critical conditions for the reacting gas; Step 6: Insert the injection tube (17) into the melt of pure element A, and inject the reaction gas into the melt of pure element A (6) through the injection tube (17); open the gas valve (19) to allow the gas in the growth chamber (11) to flow out; maintain the temperature T2 in the growth chamber (11); The reaction gas is in a supercritical fluid state and is rich in pure element A. When it encounters the plate-like seed crystal (13) on the growth substrate (12), it begins to grow and form a compound crystal. Step 7: After growth is complete, stop injecting the reaction gas, raise the injection pipe (17), open the vent valve (20), close the gas valve (19), and gradually reduce the pressure in the high-temperature chamber (2), growth chamber (11) and furnace body (1) to the ambient pressure outside the furnace body; fill the high-temperature chamber (2) with inert gas until the reaction gas is exhausted; stop heating the main heating body (4), the first auxiliary heating body (9) and the second auxiliary heating body (14), and after the room temperature is reached, cut and dismantle the equipment and take out the crystal; The pure element A reacts with the reactive gas to generate a semiconductor material.

7. The method according to claim 6, characterized in that, The pure element A and the reaction gas are indium and phosphorus, P1 is greater than 15 MPa, T1 is greater than 1062℃, and T2 is in the range of 900℃-1062℃.

8. The method according to claim 6, characterized in that, The pure element A and the reactant gas are gallium and oxygen or silicon and methane.

9. The method according to claim 6, characterized in that, Step 2 includes: Place the crucible (5) into the high-temperature main chamber (2-3) and weld the high-temperature chamber cover (2-2) to the high-temperature main chamber (2-3). Place the seed crystal (13) and the growth substrate (12) into the growth chamber (11-3), and weld the top cover (11-1) of the growth chamber to the growth chamber (11-3). Align the transfer thermostat tube (2-4) with the interface (11-2), and weld the transfer thermostat tube (2-4) to the top cover (11-1) of the growth chamber, so that the growth chamber (11) and the high temperature chamber (2) form a whole; The air inlet pipe (2-1) is connected to the air inlet (3), the transmission outlet (11-4) is connected to the air outlet (15), and the injection pipe (17) and the discharge pipe (16) are assembled. Assemble the furnace body (1) and install the first thermocouple (10-1), the second thermocouple (10-2) and the third thermocouple (10-3).

10. The method according to claim 6, characterized in that, The gas pressurization pump (21) is turned on intermittently when the amount of reaction gas passing through the injection pipe (17) decreases.

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