A method for producing a crystal of a compound by melt migration under high gravity

Abstract

The application relates to a method for preparing a compound crystal by melt migration under high gravity, and relates to the field of semiconductor preparation, and the method comprises the following steps: placing a compound semiconductor polycrystal with a molecular formula of AxBy, an element of A and a seed crystal in a crucible in sequence and closely contacting each other, horizontally placing the crucible on a centrifugal rotating device, heating the crucible to T0 (800 DEG C < T0 < T m , starting the centrifugal rotating device, and making a centrifugal force G greater than 100g; after the centrifugal force is applied, the elements A and B in the melt move to both sides of the melt pool, the polycrystal is dissolved, and the seed crystal starts to grow into a single crystal; with the polycrystal being continuously dissolved and the single crystal being continuously grown, the melt migrates to the polycrystal direction, and single crystal preparation is realized. By using the method, single crystal can be grown at low temperature, the critical shear stress of a growth interface is improved, and dislocation density is reduced. Meanwhile, the requirement of a pressure equipment and growth conditions are reduced, and a crystal which cannot be prepared by a melt method can be efficiently grown by the melt method.

Description

Technical Field

[0001] This invention relates to the field of semiconductor fabrication, and in particular to a method for preparing compound single crystals by inducing melt migration under hypergravity, especially under centrifugal force. Background Technology

[0002] Compound semiconductors are semiconductor materials composed of two or more elements. They have characteristics such as high saturation velocity, easy bandgap trimming, and wide bandgap. They have unique advantages in high power and high frequency, and play an irreplaceable role in industries such as wireless communication, power electronics, and fiber optic communication.

[0003] In current technologies, traditional melt methods such as the vertical Bridgman method, vertical temperature gradient solidification method, mold guide method, and Czochralski method are generally used to grow bulk crystals such as alumina, gallium arsenide, indium phosphide, and gallium oxide. Compound semiconductors such as silicon carbide and gallium nitride are grown using physical vapor transport methods and metal-organic chemical vapor deposition. However, the above methods are costly and inefficient.

[0004] The melt method is the lowest-cost and most efficient method for crystal preparation. However, due to the high melting point and high saturated vapor pressure of some compound semiconductors, the melt method is either too expensive or very difficult to use. Non-saturated melts can reduce both the high saturated vapor pressure and the crystallization point. However, because the growth interface of non-saturated melts is very difficult to control, and the saturation deteriorates as growth progresses, crystal preparation is quite challenging. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention is proposed.

[0006] The technical solution adopted in this invention is: a method for preparing compound crystals by melt migration under hypergravity, comprising the following steps:

[0007] A compound semiconductor polycrystalline material with the molecular formula AxBy, a single element of A, and a seed crystal are placed in close contact in a crucible, and the crucible is placed horizontally on a centrifugal rotating device.

[0008] Heat the crucible to T0, 800℃ <T0<T m T m T0 is the melting point of the compound semiconductor AxBy, where T0 is greater than the melting point of element A.

[0009] Element A melts to form a melt, the space occupied by the melt forms a molten pool, the contact surface between the melt and the seed crystal forms interface I, and the contact surface between the melt and the polycrystalline material forms interface II.

[0010] At interface I, the melt dissolves the seed crystal; at interface II, the melt dissolves the polycrystalline material, eventually forming a non-stoichiometric melt containing elements A and B, until the equilibrium composition at that temperature is reached, and the composition of the melt is C0.

[0011] Start the centrifugal rotating device and make the centrifugal force G greater than 100g;

[0012] After centrifugal force is applied, elements A and B in the melt move to both sides of the melt pool: the element that increases the liquid-solid transformation equilibrium temperature moves to interface I, and the element that decreases the liquid-solid transformation equilibrium temperature moves to interface II, and the composition in the middle and on both sides of the melt changes.

[0013] Due to the difference in composition, the liquid-solid transition equilibrium temperatures differ at the two interfaces: at interface II, a superheat ΔT is generated. h This causes the polycrystalline material to continue dissolving; at interface I, an undercooling ΔT is generated. c This causes the seed crystal to begin growing into a single crystal;

[0014] As polycrystalline materials are continuously dissolved and single crystals are continuously grown, the melt migrates towards the polycrystalline direction, thus achieving single crystal preparation.

[0015] Existing research indicates that hypergravity, as a means of enhanced separation, can separate elements in alloys, thereby purifying materials and refining the solidification structure of two alloys.

[0016] In his paper "Basic Research on the Refinement of Metal Solidification Structure and Element Segregation Behavior under Hypergravity", Yang Yuhou disclosed that under a hypergravity field of G=70g, carbon has already separated in Fe-C alloys, and the austenite grains of Fe-0.99wt%C low-carbon steel are significantly refined.

[0017] Centrifugal force is one way to generate supergravity.

[0018] This invention places an element constituting a compound semiconductor between a seed crystal and a polycrystalline material. The system is heated, and centrifugal force is applied, causing the element to melt and dissolve part of the seed crystal and polycrystalline material, forming a non-stoichiometric melt. Centrifugal force causes the element that lowers the liquid-solid transition equilibrium temperature to accumulate on the polycrystalline side, leading to its dissolution. The element that raises the liquid-solid transition equilibrium temperature moves towards the single-crystal side, increasing the crystallization point of the melt and creating supercooling. This allows the seed crystal to grow and expel another element into the melt, maintaining a constant composition in the molten pool. This process, accompanied by molten pool migration, continuously achieves single-crystal growth and polycrystalline melting, ultimately resulting in single-crystal preparation. This method is applicable to the preparation of compound semiconductors such as gallium oxide, silicon carbide, indium phosphide, and gallium arsenide.

[0019] Beneficial effects: The method proposed in this invention enables rapid growth of single crystals below the melting point of compound semiconductors, increases the critical shear stress at the growth interface, and reduces dislocation density. Simultaneously, lowering the melting point also reduces the saturated vapor pressure of the melt, lowering the requirements for pressure equipment and growth conditions, and enabling the efficient growth of crystals that were previously impossible to prepare using melt methods. Attached Figure Description

[0020] Figure 1 This is an assembly diagram of the device used in this invention.

[0021] Figure 2 This is a schematic diagram of a seed crystal crucible.

[0022] Figure 3 This is a schematic diagram of the growth crucible.

[0023] Figure 4 This is a diagram of the crucible assembly.

[0024] Figure 5 This is a schematic diagram of the present invention.

[0025] Figure 6 This is a schematic diagram of the molten pool migration during crystal growth.

[0026] Figure 7 This is a schematic diagram showing the result after single crystal growth is complete.

[0027] 1: Seed crystal; 2: Polycrystalline; 3: Element A (simple); 3-1: Interface I; 3-2: Interface II; 4: Heating wire; 5: Furnace side plate; 6: Furnace cylinder; 7: Insulation layer; 8: Thermocouple I; 9: Thermocouple II; 10: Thermocouple III; 11: Thermocouple connecting wire; 12: Outer top block; 13: Inner pad block; 14: Growth crucible; 14-1: Growth zone; 14-2; 14-3: Crucible wall; Crucible base; 15: Seed crystal crucible; 15-1: Sheath; 15-2: Seed crystal hole; 15-3: Platform; 15-4: Connecting zone; 15-5: Seed crystal cover; 16: Centrifugal rotary motor; 17: Centrifugal spindle; 18: Slider I; 19: Slider II; 20: Connecting rod; 21: Polycrystalline fragments; 22: Molten pool; 23: Gas charging / discharging pipeline. Detailed Implementation

[0028] A method for preparing compound crystals by melt migration under hypergravity, using a compound semiconductor polycrystalline material with the molecular formula AxBy, a single crystal of element A, and a seed crystal.

[0029] Compound semiconductors are denoted by AxBy, where A is one element, B is another element, and x and y represent the stoichiometric ratio of the semiconductor, such as indium phosphide (InP), gallium oxide (Ga2O3), and silicon carbide (SiC). The purpose of using elemental substances is to form a low-melting-point melt that dissolves polycrystalline and single-crystal compounds. Centrifugal force redistributes the A and B elements in the unequal melt, lowering the melting temperature at the polycrystalline interface and raising the growth temperature at the single-crystal interface, thus achieving single-crystal preparation.

[0030] According to the naming rules of chemical formulas, in AxBy, A is a metallic element such as gallium, indium, etc., or a semiconductor element such as silicon, germanium, etc., and B is a non-metallic element such as oxygen, carbon, phosphorus, arsenic, etc.

[0031] In principle, either element A or element B can achieve the above objective, but element B could be a gaseous element such as oxygen, or carbon, which has an extremely high melting point, making both unsuitable. This invention uses element A in its elemental form to prepare single crystals.

[0032] In this invention, element A is a metallic or non-metallic element with a melting point below 2000℃ and that is not easily volatile, such as In, Ga, Al, Si, Ge, etc.

[0033] The method includes the following steps: placing a compound semiconductor polycrystalline material with the molecular formula AxBy, a single element of A, and a seed crystal in close contact in sequence in a crucible, and then placing the crucible horizontally on a centrifugal rotating device.

[0034] Heat the crucible to T0, 800℃ <T0<T m T m T0 is the melting point of the compound semiconductor AxBy, where T0 is greater than the melting point of element A.

[0035] Element A melts to form a melt, and the space occupied by the melt forms a molten pool. The contact surface between the melt and the seed crystal forms interface I, and the contact surface between the melt and the polycrystalline material forms interface II. Initially, the melt contains only element A.

[0036] At interface I, the melt dissolves the seed crystal; at interface II, the melt dissolves the polycrystalline material. The melt contains elements A and B, eventually forming a non-stoichiometric melt containing elements A and B, until the equilibrium composition at that temperature is reached, and the composition of the melt is CO.

[0037] At this point, if the temperature remains constant and the melt remains stationary, the liquid-solid transformation equilibrium temperatures at interfaces I and II, as well as in the middle of the melt, are the same, and equilibrium can be achieved. The melt will no longer dissolve the seed crystal and polycrystalline material.

[0038] "Liquid-solid transition equilibrium temperature": The melting point and crystallization point of the compound. The content of elements A and B affects the melting point and crystallization point of the melt ("liquid-solid transition equilibrium temperature").

[0039] The content of each element in a melt at equilibrium varies depending on the melt temperature. If the temperature is Tm, the content of each element in the melt is the proportion shown in the molecular formula; if the temperature is set to T0, the composition of the melt is C. Different compositions result in different equilibrium temperatures for the liquid-solid transition.

[0040] Setting a temperature T0 determines the composition of the melt at that temperature, and also determines the liquid-solid transition equilibrium temperature of the melt as T0.

[0041] The aforementioned "dissolution" can also be described as "erosion," which can be compared to water dissolving solid sugar or salt.

[0042] Start the centrifugal rotating device at a speed of 5-50 rad / s 2 The acceleration is gradually increased by the rotational speed until the centrifugal force G is greater than 100g.

[0043] Under the action of centrifugal force, elements A and B of different densities move to both sides of the molten pool. By setting the positions of the seed crystal and polycrystal relative to the centrifugal rotation axis, the following can be achieved: the element that increases the liquid-solid transformation equilibrium temperature moves to interface I, and the element that decreases the liquid-solid transformation equilibrium temperature moves to interface II. The composition of the melt in the middle and both sides of the molten pool changes.

[0044] Due to the difference in composition, the liquid-solid transition equilibrium temperatures at the two interfaces are different:

[0045] At interface II, the actual temperature is T0. Due to the movement of elements, the liquid-solid transition equilibrium temperature decreases, resulting in a superheat ΔT. h This leads to the continued dissolution of polycrystalline material;

[0046] At interface I, the actual temperature is T0. Due to the movement of elements, the liquid-solid transition equilibrium temperature increases, resulting in a supercooling ΔT. c This allows the seed crystal to continuously grow into a single crystal.

[0047] As polycrystalline materials are continuously dissolved and single crystals are continuously grown, the melt migrates towards the polycrystalline direction, thus achieving single crystal preparation.

[0048] The melt in the molten pool contains two elements, A and B. One of the key points of this invention is to increase the liquid-solid transformation equilibrium temperature at the interface between the seed crystal and the melt, and to decrease the liquid-solid transformation equilibrium temperature at the interface between the polycrystalline material and the melt. This requires setting the positions of the seed crystal and the polycrystalline material relative to the centrifugal spindle according to the characteristics of the elements.

[0049] There are four possible scenarios, as shown in the table below:

[0050] 1 In the AB melt system, increasing element A lowers the melting point, while increasing element B raises the melting point, and element A has a higher density than element B. Seed crystals are closer to the centrifugal axis, while polycrystalline crystals are farther away from the centrifugal axis. 2 In the AB melt system, increasing element A lowers the melting point, while increasing element B increases the melting point. Furthermore, element A has a lower density than element B. Polycrystalline silicon is closer to the centrifugal axis, while seed crystal is farther away from the centrifugal axis. 3 In the AB melt system, increasing element A raises the melting point, while increasing element B lowers the melting point. Furthermore, element A has a higher density than element B. Polycrystalline crystals are closer to the centrifugal axis, while seed crystals are farther away from the centrifugal axis. 4 In the AB melt system, increasing element A raises the melting point, while increasing element B lowers the melting point. Furthermore, the density of element A is less than that of element B. Seed crystals are closer to the centrifugal axis, while polycrystalline crystals are farther away from the centrifugal axis.

[0051] This invention also proposes a method for preparing compound crystals through melt migration under hypergravity using specialized equipment.

[0052] See Figure 1 The device includes a centrifugal rotary motor 16, a centrifugal spindle 17 connected to the centrifugal rotary motor 16, a connecting rod 20 connected to the centrifugal spindle 17 and arranged horizontally, and a crystal growth device connected to the connecting rod 20.

[0053] The crystal growth equipment includes a furnace side plate 5 connected to a connecting rod 20, a furnace cylinder 6 connected to the furnace side plate 5 and forming a closed space, an insulation layer 7 is set close to the furnace cylinder 6 in the closed space, a combined crucible and heating wires 4 around the combined crucible are placed in the insulation layer 7, and an outer top block 12 and an inner pad block 13 are respectively at both ends of the combined crucible; the crystal growth equipment is placed horizontally.

[0054] The combined crucible includes a growth crucible 14 and a seed crystal crucible 15 that are placed horizontally and combined with each other.

[0055] See Figure 3 The growth crucible 14 includes a crucible base 14-2 and a crucible wall 14-3 forming the growth zone 14-1.

[0056] See Figure 2 The seed crystal crucible 15 includes a sleeve 15-1, a seed crystal cover 15-5 connecting the sleeve 15-1, and a platform 15-3 inside the sleeve 15-1. The space between the platform 15-3 and the seed crystal cover 15-5 is the seed crystal hole 15-2, and the space above the platform 15-3 is the connecting area 15-4. The included angle θ between the seed crystal cover 15-5 and the sleeve 15-1 is between 70° and 85°, and the seed crystal is matched with this angle to prevent the seed crystal from moving.

[0057] The inner diameter of the inner layer 15-1 is larger than the outer diameter of the crucible wall 14-3, and the difference between the two diameters is less than 2mm, so the two can be tightly joined together.

[0058] The device also includes thermocouples I8, II9, and III10 disposed on the side of the combined crucible. Thermocouple I8 transmits signals through the furnace side plate 5, the slider I18 connected to the centrifugal main shaft 17, and the thermocouple connecting line 11. Thermocouples II9 and III10 transmit signals through the furnace side plate 5, the slider II19 connected to the centrifugal main shaft 17, and the thermocouple connecting line 11.

[0059] Two to four crystal growth devices are evenly arranged around the centrifugal spindle 17.

[0060] Take indium phosphide (InP) as an example. Indium has a higher density than phosphorus. In a phosphorus-indium melt, adding indium will lower the liquid-solid transition equilibrium temperature of the melt, while adding phosphorus will raise the liquid-solid transition equilibrium temperature of the melt.

[0061] The specific steps of the method for preparing compound crystals by melt migration under hypergravity using the above-mentioned device are as follows:

[0062] Step 1

[0063] 1. Place the polycrystalline indium phosphide fragments 21 in the growth crucible 14, heat them to melt them and then cool them down to solidify them into polycrystalline indium phosphide 2. The purpose is to make the polycrystalline indium phosphide 2 in close contact with the growth crucible 14, so as to prevent the centrifugal force from squeezing the melt 3 in the molten pool 22 into the gap in subsequent steps.

[0064] The element A, in this embodiment, is indium, and is placed on the surface of polycrystalline material 2. The element A, in its 3rd element, is disk-shaped, and its outer diameter is the same as the inner diameter of the growth crucible 14.

[0065] The inner surface of the sleeve 15-1 in the seed crystal crucible 15 is assembled with the outer surface of the growth region 14-1 of the growth crucible 14. The top of the crucible wall 14-3 abuts against the platform 15-3. The seed crystal 1 is placed in the seed crystal hole 15-2, and the seed crystal hole 15-2 is sealed with the seed crystal cover 15-5. The growth crucible 14 and the seed crystal crucible 15 form a combined crucible, as shown below. Figure 4 As shown.

[0066] 2. Place the combined crucible in the furnace cylinder 6 and fix the combined crucible by the outer top block 12 and the inner pad block 13.

[0067] The outer side of the combined crucible is a heating wire 4, and the outer side of the heating wire 4 is an insulation layer 7. Thermocouples I8, II9, and III10 are arranged through the insulation layer 7. The temperature measuring heads of thermocouples I8, II9, and III10 pass through the inner wall of the insulation layer 7 and approach the outer wall of the combined crucible.

[0068] Thermocouple I8 outputs temperature signals via slider I18 connected to furnace side plate 5, and thermocouples II9 and III10 output temperature signals via slider II19 connected to furnace side plate 5.

[0069] The above steps complete the assembly of the crystal growth equipment. There can be 2-4 crystal growth devices; in this embodiment, two crystal growth devices are assembled.

[0070] 3. Fix the furnace cylinder 6 to the furnace side plate 5, and fix the furnace side plate 5 to the connecting rod 20. The connecting rod 20 is connected to the centrifugal main shaft 17.

[0071] Two crystal growth devices are symmetrically arranged on both sides of the centrifugal spindle 17. If there are more than two, they are evenly arranged around the perimeter of the centrifugal spindle 17.

[0072] Since indium has a higher density than phosphorus, adding indium to a phosphorus-indium melt will lower the liquid-solid transition equilibrium temperature of the melt. Therefore, in this embodiment, the combined crucible is placed with the seed crystal 1 close to the centrifugal spindle 17.

[0073] The above process completes the assembly of the device, such as Figure 1 As shown.

[0074] The furnace body space formed by the furnace cylinder 6 and the furnace side plate 5 is evacuated to 100Pa through the gas filling and venting pipeline 23, and then inert gas is filled in to a pressure of 3MPa-4MPa.

[0075] The combined crucible is heated by heating wire 4, and the temperature is detected by thermocouples I8, II9, and III10 until it reaches temperature T0.

[0076] Theoretically, crystal growth can be achieved as long as T0 is greater than the melting point of element A. Under the same centrifugal force, the higher T0, the faster the crystal grows; if T0 is too low, the growth process will be very slow. Therefore, in this embodiment, T0 is limited to 800°C. <T0<T m .

[0077] The element A, element 3 (indium in this embodiment), is melted into a melt, which occupies the space to form a molten pool 22. The melt dissolves part of the seed crystal 1 and polycrystal 2, forming an indium-phosphorus non-proportional binary melt in the molten pool. The binary melt composition is CO, and it forms the interface I3-1 between the seed crystal 1 and the melt and the interface II3-2 between the polycrystal 2 and the melt.

[0078] Step 2: Start the centrifugal rotary motor 16 to drive the furnace cylinder 6 to rotate at a speed of 5-50 rad / s. 2 The speed is gradually increased until the centrifugal force G is greater than 100g.

[0079] Centrifugal force G is usually expressed as a multiple of g (gravitational acceleration). The conversion formula between G and rotational speed is as follows:

[0080] G=1.11×10 -5 ×R×ω 2 ×g, G is centrifugal force, ω is rotational speed (in rpm), and R is radius (in centimeters).

[0081] In this embodiment, the radius R can be regarded as the distance from the furnace side plate 5 to the centrifugal main shaft 17.

[0082] The rotational speed of the centrifugal rotary motor 16 can be calculated using the above formula.

[0083] Experiments show that a centrifugal force G greater than 50g can cause the separation of elements in the melt. To accelerate the separation of elements and thus the synthesis speed, G is set to be greater than 100g in this embodiment.

[0084] Under the action of centrifugal force, the indium element in the melt in molten pool 22 moves towards the polycrystalline 2 side, and the composition of the melt at interface II3-2 reaches C. h This generates a superheat ΔT h This leads to the dissolution of polycrystalline 2; the phosphorus element in the melt in the molten pool 22 moves towards the single crystal 1 side, and the composition of the melt at interface I3-1 reaches C c This produces a supercooling ΔT c This causes seed crystal 1 to begin growing into a single crystal and expelling indium into the melt, such as Figure 5 As shown.

[0085] Figure 5 In the graph, the upper coordinate system has a horizontal axis representing composition (C) and a vertical axis representing temperature (T). The curves in the graph represent the liquid-solid transition equilibrium temperatures for different compositions in the melt. The lower coordinate system has a horizontal axis representing position (L), starting at the bottom of seed 1, and a vertical axis representing composition (C). The curves in the graph represent the composition of the melt at different positions within the molten pool 22. The horizontal axis in this graph is set in the opposite direction to the conventional setting; if the position of seed 1 is different, the starting position and direction of the horizontal axis will change.

[0086] In this embodiment, the proportion of element A (indium in this embodiment) in the melt is C. h >C0>C c The proportion of element B (phosphorus in this example) in the melt is C. h <C0<C c The result is that the melt at different locations in molten pool 22 contains different compositions and has different liquid-solid transition equilibrium temperatures. The melt with composition C0 has a liquid-solid transition equilibrium temperature of T0, while the melt with composition C... h The melt has a liquid-solid transition equilibrium temperature less than T0 and a composition of C. c The melt has a liquid-solid transition equilibrium temperature greater than T0.

[0087] As polycrystalline 2 is continuously dissolved and crystals continue to grow, the molten pool 22 migrates towards polycrystalline 2, ultimately achieving single crystal preparation.

[0088] In this embodiment, during this process, the seed crystal 1 grows in a direction away from the centrifugal main axis 17, such as... Figure 6 As shown.

[0089] Conduct 3-5 sets of experiments, removing samples at 1 hour, 2 hours, and 3 hours respectively, and test the movement speed of interface I3-1; determine the single crystal growth time based on the movement speed and the amount of material.

[0090] Step 3: Repeat steps 1-2 to complete the single crystal preparation according to the sample single crystal growth time, such as... Figure 7 As shown. After growth is complete, the apparatus is removed and the single crystal is taken out.

Claims

1. A method for preparing compound crystals by melt migration under hypergravity, characterized in that, The method includes the following steps: A compound semiconductor polycrystalline material with the molecular formula AxBy, a single element of A, and a seed crystal are placed in close contact in a crucible, and the crucible is placed horizontally on a centrifugal rotating device. The crucible is heated to To, 800°C < To < T m , T m is the melting point of the compound semiconductor AxBy, and To is greater than the melting point of the A element. Element A melts to form a melt, the space occupied by the melt forms a molten pool, the contact surface between the melt and the seed crystal forms interface I, and the contact surface between the melt and the polycrystalline material forms interface II. At interface I, the melt dissolves the seed crystal; at interface II, the melt dissolves the polycrystalline material, eventually forming a non-stoichiometric melt containing elements A and B, until the equilibrium composition at that temperature is reached, and the composition of the melt is C0. Start the centrifugal rotating device and make the centrifugal force G greater than 100g; After centrifugal force is applied, elements A and B in the melt move to both sides of the melt pool: the element that increases the liquid-solid transformation equilibrium temperature moves to interface I, and the element that decreases the liquid-solid transformation equilibrium temperature moves to interface II, and the composition in the middle and on both sides of the melt changes. Due to the difference in composition, the liquid-solid transition equilibrium temperature is different at the two interfaces: at interface II, an over-temperature ΔT h is generated, causing the polycrystal to continue to be dissolved; at interface I, an under-temperature ΔT c is generated, causing the seed crystal to start to grow into a single crystal; As polycrystalline materials are continuously dissolved and single crystals are continuously grown, the melt migrates towards the polycrystalline direction, thus achieving single crystal preparation.

2. The method according to claim 1, characterized in that, If the density of element A is greater than that of element B, and increasing the amount of element A will lower the liquid-solid transition equilibrium temperature of the melt, or if the density of element A is less than that of element B, and increasing the amount of element A will raise the liquid-solid transition equilibrium temperature of the melt, then the seed crystal will be closer to the rotation axis of the centrifugal rotating device; otherwise, the polycrystalline crystal will be closer to the rotation axis of the centrifugal rotating device.

3. The method according to claim 1, characterized in that, The method is implemented using a centrifugal force driven apparatus for preparing compound crystals, the apparatus including a centrifugal rotary motor (16), a centrifugal spindle (17) connected to the centrifugal rotary motor (16), a horizontally arranged connecting rod (20) connected to the centrifugal spindle (17), and a crystal growth device connected to the connecting rod (20); The crystal growth equipment is placed horizontally and includes a furnace side plate (5) connected to a connecting rod (20) and a furnace cylinder (6) connected to the furnace side plate (5) to form a closed space. A heat insulation layer (7) is set close to the furnace cylinder (6) in the closed space. A combined crucible and heating wires (4) around the combined crucible are placed in the heat insulation layer (7). There are outer top blocks (12) and inner pad blocks (13) at both ends of the combined crucible. The combined crucible includes a growth crucible (14) and a seed crystal crucible (15) that are placed horizontally and combined with each other. The growth crucible (14) includes a crucible base (14-2) and a crucible wall (14-3) forming the growth zone (14-1). The seed crystal crucible (15) includes a sleeve (15-1), a seed crystal cover (15-5) connecting the sleeve (15-1), and a platform (15-3) inside the sleeve (15-1). The space between the platform (15-3) and the seed crystal cover (15-5) is the seed crystal hole (15-2), and the space above the platform (15-3) is the connecting area (15-4).

4. The method according to claim 3, characterized in that, The angle (θ) between the seed crystal cap (15-5) and the outer layer (15-1) is between 70° and 85°.

5. The method according to claim 3, characterized in that, The device also includes thermocouples I (8), II (9) and III (10) disposed on the side of the combined crucible.

6. The method according to any one of claims 3-5, characterized in that, There are 2-4 crystal growth devices, which are evenly arranged around the centrifugal spindle (17).

7. The method according to claim 6, characterized in that, The method includes: Step 1: Place the polycrystalline compound semiconductor fragment (21) with the molecular formula AxBy into the growth crucible (14), heat it to melt it and cool it down to solidify it into a polycrystalline (2), so that the polycrystalline (2) is in close contact with the growth crucible (14); place the elemental substance (3) of element A on the surface of the polycrystalline (2); The inner surface of the inner layer (15-1) of the seed crystal crucible (15) is assembled with the outer surface of the growth area (14-1) of the growth crucible (14), and the seed crystal (1) is placed in the seed crystal hole (15-2). The seed crystal hole (15-2) is covered by the seed crystal cover (15-5); the growth crucible (14) and the seed crystal crucible (15) form a combined crucible. The combined crucible is placed in the furnace cylinder (6) and fixed by the outer top block (12) and the inner pad block (13); Fix the furnace cylinder (6) to the furnace side plate (5) and fix the furnace side plate (5) to the connecting rod (20); The furnace body space formed by the furnace cylinder (6) and the furnace side plate (5) is evacuated to 100Pa, and then filled with inert gas at a pressure of 3MPa-4MPa. The combined crucible is heated to temperature T0 by heating wire (4); Step 2: Start the centrifugal rotary motor (16) to drive the furnace cylinder (6) to rotate at a speed of 5-50 rad / s 2 The acceleration is gradually increased by the rotational speed until the centrifugal force G is greater than 100g; Step 3: After growth is complete, remove the device and take out the single crystal.

8. The method according to claim 7, characterized in that, The element A (3) is disk-shaped, and its outer diameter is the same as the inner diameter of the growth crucible (14).

9. The method according to claim 7, characterized in that, In step 1, if the density of element A is greater than that of element B, and the increase of element A will lower the liquid-solid transition equilibrium temperature of the melt, or if the density of element A is less than that of element B, and the increase of element A will raise the liquid-solid transition equilibrium temperature of the melt, the seed crystal crucible (15) in the combined crucible is brought close to the centrifugal main shaft (17). Otherwise, place the growth crucible (14) in the combined crucible close to the centrifugal spindle (17).

Images