Continuous feeding LEC crystal growth device and crystal growth method

Abstract

The invention relates to the technical field of crystal growth, in particular to a continuous feeding LEC crystal growth device and a crystal growth method. The crystal growth method comprises the following steps: S1, fixing an auxiliary crucible in a main crucible; s2, crystal raw materials are added into the main crucible and melted; s3, the heated dopant in the dopant injection chamber is added to a doping area in the auxiliary crucible; s4, the liquid sealing melt is injected into the chamber, and the heated liquid sealing melt is added into a crystal pulling area in the auxiliary crucible; s5, the main crucible and the auxiliary crucible are rotated, the seed rod is rotated and lifted, and the seed rod is annealed through an annealing heater; s6, the material supplementing amount is calculated, and the heated crystal melt in the material supplementing crucible is added to a material supplementing area between the main crucible and the auxiliary crucible; s7, the doping agent supplementing amount is calculated based on the supplementing amount, the crystal melt feeding amount and the doping agent feeding amount, the doping agent is added into the auxiliary crucible, and continuous feeding in the growth process of large-size crystals can be effectively guaranteed through the crystal growth method.

Description

Technical Field

[0001] The invention relates to the technical field of crystal growth, and in particular to a continuous feeding LEC crystal growth device and a crystal growth method. Background Art

[0002] The Liquid Encapsulating Czochralski (LEC) method uses a multi-heater growth furnace and a reusable PBN (pyrolytic boron nitride) crucible to grow crystals under a specific atmosphere, and has the following advantages: the liquid encapsulating fluid inhibits the evaporation of the crystal melt and inhibits the free interface thermal capillary convection, and can stably grow high-quality single crystals, especially in the growth of large-diameter cylindrical single crystals; the crystals grown by the LEC method are easy to carry out subsequent wafer processing, have controllable carbon content and good semi-insulating properties; it is not only suitable for the growth of GaAs single crystals, but also can be used for the growth of other compound semiconductor single crystals such as GaP, InP, GaSb, etc., and has good applicability.

[0003] The Chinese patent with publication number CN113308739B proposes a crystal growth device combining LEC with VGF (Vertical Gradient Freezing) method. The growth crucible of the lower LEC is pre-loaded with metal melt and liquid sealing fluid. Two synthesis systems are set above the LEC crucible, which can add non-metallic fluid to the LEC crucible to improve the purity of LEC grown crystals and reduce the crystal synthesis time. However, the current LEC method cannot achieve the function of continuous feeding, and it is often necessary to stop the furnace for material replacement, which not only interrupts the growth process, but also increases the downtime. The interruption of the growth process will lead to a decrease in crystal quality, and the increase in downtime will lead to a decrease in production efficiency.

[0004] In order to grow large-sized crystals, a Chinese patent with publication number CN112144108A proposes a crystal growth furnace and a crystal production process, in which the crystal growth crucible is made into a double crucible form, that is, the crucible for growing crystals is made into a double-layer structure, the inner crucible is a cylinder with a diameter smaller than the outer crucible, the inner crucible is fixed to the outer crucible at the bottom by welding, and the bottom of the inner crucible has holes that can melt the supplementary material in the melt zone between the inner and outer crucibles and diffuse it into the inner crucible to replenish the raw material consumption after the inner crucible pulls the crystal. However, this inner crucible is a type of crucible that cannot be moved, and the temperature of the inner crucible can only rely on heat conduction of the molten liquid, which makes it difficult to melt the raw material in the inner crucible before pulling the crystal, increasing the melt operation cost and operation time. Chinese patents with publication numbers CN1329559C and CN1 16411350A propose a growth method of a hanging crucible, in which a refractory cylinder is placed vertically on a coaxial support disc of an outer crucible, and a horizontally placed inner crucible is fixed on the upper end of the cylinder, and the inner crucible can rotate and move up and down with the crucible axis. It can realize the separation of the inner and outer crucibles before melting and the formation of a feeding area between the inner and outer crucibles after unloading. However, this structure also requires the setting of an external ceramic crucible, which is complex in structure, and when a three-zone crucible is required to increase the doping area, the newly added cylinder cannot be fixed. Chinese patents with publication numbers CN102485976A propose a hanging three-crucible automatic continuous feeding system, which fixes a double-layer cylindrical crucible through an upper and lower transmission mechanism and drives it into the outer crucible to form three areas: a material zone, a transition zone, and a growth zone. The upper and lower transmission mechanisms are fixed on the refractory outer shell, and the outer shell rotates coaxially with the crucible axis, so the double-layer crucible can rotate coaxially with the outer crucible. However, this type of crystal growth device is designed for the growth of stoichiometric lithium niobate single crystals. The number and radial distance of the inner crucibles cannot be adjusted, and the crucible structure cannot be adjusted according to the growth of different crystals. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a continuous feeding LEC crystal growth device and a crystal growth method. The above-mentioned crystal growth method can effectively solve the problem of continuous feeding difficulties in the growth of large-size crystals LEC, so as to facilitate the growth of various crystals such as large-size single crystal silicon, polycrystalline silicon and compound crystals, and the continuous feeding LEC crystal growth device is used to implement the crystal growth method.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a continuous feeding LEC crystal growth device, comprising a base, a main furnace body, a main crucible, a sub-crucible, a driving member and a seed crystal rod, wherein the main furnace body, the main crucible and the driving member are all installed on the base, the main crucible is located in the main furnace body, the sub-crucible is installed in the main crucible and is connected with the main crucible, the seed crystal rod is slidably arranged on the main furnace body and the lower end is located in the sub-crucible, the driving end of the driving member is connected to the seed crystal rod and is used to drive the seed crystal rod to rotate and move up and down; a main crucible heater is installed on the main crucible, characterized in that the sub-crucible adopts a single-layer or double-layer sub-crucible, and further comprises:

[0008] A feeding crucible is installed on the main furnace body, a feeding crucible heater is installed on the feeding crucible, the bottom of the feeding crucible is connected to a crystal feeding pipe extending to the feeding area of ​​the main crucible, and a first high-temperature solenoid valve is installed on the crystal feeding pipe; a dopant injection chamber is installed on the main furnace body, a dopant injection chamber heater is installed on the dopant injection chamber, the bottom of the dopant injection chamber is connected to a dopant feeding pipe, and a third high-temperature solenoid valve is installed on the dopant feeding pipe; a plurality of weighing devices are installed on the base, the main crucible is installed on the base through the weighing devices, the weighing devices are electrically connected to a PID controller, and the PID controller is electrically connected to the first high-temperature solenoid valve and the third high-temperature solenoid valve respectively; by setting the PID controller, the weighing device and the corresponding feeding and doping components, it is possible to effectively calculate how much material needs to be added, and it is possible to effectively solve the problem of continuous feeding difficulties in the growth of large-size crystals LEC, so as to facilitate the growth of various crystals such as large-size single crystal silicon, polycrystalline silicon and compound crystals. At the same time, whether to use a double-layer or single-layer auxiliary crucible can be determined according to whether dopants are needed, which has wider applicability.

[0009] Optionally, a rotating rod is rotatably penetrated at the bottom of the base, the rotating rod is penetrated at the bottom of the main crucible and the end face does not contact the main crucible, the rotating rod is used to rotate the main crucible, a universal ball is installed on the weighing device, an annular groove is provided at the bottom of the main crucible, the universal ball is located in the annular groove, the rotating rod can be externally connected to a rotating device, thereby driving the main crucible and the auxiliary crucible to rotate, and does not affect the weighing of the weighing device, thereby improving the effect of crystal growth.

[0010] Optionally, a liquid-sealed melt injection chamber is installed on the main furnace body, a liquid-sealed melt injection chamber heater is installed on the liquid-sealed melt injection chamber, a liquid-sealed melt feeding pipe is connected to the bottom of the liquid-sealed melt injection chamber, and a second high-temperature solenoid valve electrically connected to the PID controller is installed on the liquid-sealed melt feeding pipe. The liquid-sealed melt can seal the crystal melt to avoid contamination of the crystal melt by external gas, thereby improving the quality of crystal growth.

[0011] Optionally, an annealing heater is installed on the inner wall of the top of the main furnace body, which can anneal the crystal, thereby ensuring the structural quality of the crystal.

[0012] Optionally, the main crucible and the auxiliary crucible are fixed by a fixing arm to ensure the stability of the structure between the auxiliary crucible and the main crucible, and when the auxiliary crucible needs to be replaced, the auxiliary crucible can be directly disassembled.

[0013] Optionally, the main furnace body is connected with a vacuum tube and a gas filling tube to realize vacuuming and filling of the main furnace body with inert gas.

[0014] In a second aspect, the present invention provides a crystal growth method, comprising the following steps:

[0015] S1: Select a sub-crucible and a fixed arm according to the type of growing crystal, and fix the sub-crucible in the main crucible through the fixed arm;

[0016] S2: adding the crystal raw material to be grown into the main crucible, heating the main crucible heater, and melting the crystal raw material in the main crucible;

[0017] S3: If a dopant is required for crystal growth, the heater of the dopant injection chamber is heated, and then the heated dopant is added into the doping area in the auxiliary crucible in the dopant injection chamber. If a dopant is not required for crystal growth, this step is omitted.

[0018] S4: heating the heater of the liquid sealing melt injection chamber, injecting the liquid sealing melt into the chamber, and adding the heated liquid sealing melt into the crystal pulling area in the auxiliary crucible;

[0019] S5: When the crystal grows on the seed crystal rod, the main crucible and the auxiliary crucible are rotated, the seed crystal rod is rotated and gradually raised, and the seed crystal rod is annealed by an annealing heater;

[0020] S6: Calculate the feeding amount through the PID controller and the weighing device, heat the feeding crucible heater, and then add the heated crystal melt in the feeding crucible to the feeding area between the main crucible and the auxiliary crucible;

[0021] S7: If a dopant is required for crystal growth, a dopant supplement amount is calculated based on the weight measured by the weigher by a PID controller, and the dopant is added to the doping region in the sub-crucible.

[0022] By adopting the above method, whether the crystal growth requires dopants or not, continuous feeding can be performed, and the feeding amount is controllable, thereby effectively solving the problem of continuous feeding difficulties in the growth of large-sized crystal LEC, so as to facilitate the growth of large-sized single crystal silicon, polycrystalline silicon and compound crystals. At the same time, the type of auxiliary crucible to be used can be determined according to the actual situation of the growing crystal, which has higher applicability.

[0023] Optionally, the power p1(t) of the main crucible heater is:

[0024]

[0025] Among them, err1(t) represents the deviation between the crystal growth weight and the set value, Kp1, K i1 , Kd1 represent the proportional band constant, integral constant and differential constant that control crystal growth respectively.

[0026] Optionally, the power p2(t) of the feeding crucible heater is:

[0027]

[0028] Among them, err2(t) represents the deviation between the actual added weight of the crystal melt and the weight of the crystal growth, Kp2, K i2 , Kd2 represent the proportional band constant, integral constant and differential constant for controlling the heating power of the feeding crucible heater respectively.

[0029] Optionally, the power p3(t) of the dopant implantation chamber heater is:

[0030]

[0031] Among them, err3(t) represents the deviation between the actual added weight of the crystal melt and the weight of the crystal growth, Kp3, K i3 , Kd3 represent the proportional band constant, integral constant, and differential constant for controlling the heating power of the heater in the dopant injection chamber, respectively.

[0032] Optionally, the heating temperature of the feeding crucible is 10-50° C. higher than the crystal growth temperature.

[0033] In summary, the present invention at least includes the following beneficial technical effects:

[0034] 1. During crystal growth, the main crucible heater and the annealing heater can be heated at the same time to ensure the melting of the crystal. The setting of the weighing device and the PID controller can ensure the accuracy of the feeding amount and the weight of the dopant, and the detachable setting of the double-layer / single-layer auxiliary crucible can ensure the applicability of the growth device, thereby effectively solving the problem of continuous feeding difficulties in the growth of large-size crystals LEC, so as to facilitate the growth of various crystals such as large-size single crystal silicon, polycrystalline silicon and compound crystals.

[0035] 2. The main crucible and the auxiliary crucible can be rotated continuously during weighing, which can improve the growth effect of large-size crystals, and can be carried out simultaneously without interfering with the weighing device. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic structural diagram of a continuous feeding LEC crystal growth device in an embodiment of the present invention.

[0037] Figure 2 It is a schematic diagram of the cross-sectional structure of a single-layer cylindrical auxiliary crucible.

[0038] Figure 3 It is a schematic diagram of the cross-sectional structure of a double-layer cylindrical auxiliary crucible.

[0039] Figure 4 Schematic diagram of the connection structure between the auxiliary crucible and the fixed arm.

[0040] Figure 5 Three views of the fixed arm.

[0041] Figure 6 4 is a flow chart of the crystal growth method in an embodiment of the present invention.

[0042] Explanation of the reference numerals: 1. base; 2. main furnace body; 3. main crucible; 4. auxiliary crucible; 5. connecting hole; 6. feeding area; 7. doping area; 8. crystal pulling area; 81. liquid-sealed melt; 9. fixed arm; 10. main crucible heater; 11. linear drive; 12. seed crystal rod; 13. annealing heater; 14. feeding crucible; 15. feeding crucible heater; 16. crystal feeding tube; 17. first high-temperature solenoid valve; 18. liquid-sealed melt injection chamber; 19. liquid-sealed melt injection chamber heater; 20. liquid-sealed melt injection tube; 21. liquid-sealed melt feeding tube; 22. second high-temperature solenoid valve; 23. dopant injection chamber; 24. dopant injection chamber heater; 25. dopant injection tube; 26. dopant feeding tube; 27. third high-temperature solenoid valve; 28. vacuum tube; 29. ​​inflation tube; 30. weighing device; 31. rotating rod. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] The terms used in the following embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to be used as limitations of the present invention. As used in the specification of the present invention and the appended claims, the singular expressions "one", "a kind of", "said", "above", "the" and "this" are intended to also include plural expressions, unless there is a clear contrary indication in its context. It should also be understood that the term "and / or" used in the present invention refers to and includes any or all possible combinations of one or more listed items. The term "exemplary" means "used as an example, embodiment or illustrative", and any embodiment described as "exemplary" here does not have to be interpreted as being superior to or better than other embodiments. The terms "first" and "second" are only used for descriptive purposes, and cannot be understood as implying or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" can expressly or implicitly include one or more of these features, and in the description of the embodiments of the present invention, unless otherwise specified, the meaning of "multiple" is two or more.

[0045] The embodiment of the present invention provides a continuous feeding LEC crystal growth device.

[0046] refer to Figure 1 A continuous feeding LEC crystal growth device includes a base 1, a main furnace body 2 and a main crucible 3 are installed on the base 1, the main crucible 3 is located in the main furnace body 2, and the main crucible 3 is used to hold crystal melt. A secondary crucible 4 is installed in the main furnace body 2, and the secondary crucible 4 is used to supplement the crystal melt and / or dopant during the growth process. The secondary crucible 4 is selected according to the type of the growing crystal raw material. The secondary crucible 4 adopts a single-layer cylindrical secondary crucible or a double-layer cylindrical secondary crucible, and the secondary crucible 4 has no bottom.

[0047] refer to Figure 1 , Figure 2 and Figure 3 If a large-sized silicon crystal is grown, a single-layer cylindrical auxiliary crucible can be used. If a composite crystal such as lithium niobate is grown and a dopant is required, a double-layer cylindrical auxiliary crucible can be used. A plurality of connecting holes 5 are provided below the auxiliary crucible 4. When the auxiliary crucible 4 is a single-layer cylindrical auxiliary crucible, the crystal melt can flow from the feeding area 6 in the main crucible 3 to the crystal pulling area 8 in the auxiliary crucible 4 through the connecting holes 5; when the auxiliary crucible 4 is a double-layer cylindrical auxiliary crucible, the crystal melt can flow from the feeding area 6 in the main crucible 3 to the doping area 7 and the crystal pulling area 8 in the auxiliary crucible 4 through the connecting holes 5.

[0048] It should be understood that the main crucible 3 and the auxiliary crucible 4 are preferably cylindrical, and may also be other shapes, and should not be limited. When the auxiliary crucible 4 is a double-layer cylindrical auxiliary crucible, a plurality of connecting holes 5 are provided on the double-layer side walls, the area between the main crucible 3 and the auxiliary crucible 4 is a feeding area 6, the area between the double-layer side walls of the auxiliary crucible 4 is a doping area 7, and the area in the inner layer of the auxiliary crucible 4 is a crystal pulling area 8. When the auxiliary crucible 4 is a single-layer cylindrical auxiliary crucible, the doping area 7 does not exist.

[0049] Among them, reference Figure 4 and Figure 5 , and the main crucible 3 and the auxiliary crucible 4 are fixed by bolts through a fixed arm 9, one end of the fixed arm 9 is bolted to the opening edge of the main crucible 3, and the other end is bolted to the opening edge of the auxiliary crucible 4. The fixed arm 9 is used in plurality, and the plurality of fixed arms 9 are arranged around the central axis of the auxiliary crucible 4 at equal intervals. In the embodiment of the present application, the number of fixed arms 9 is four. The specifications of the fixed arm 9 are selected according to the specifications of the auxiliary crucible 4 to ensure adaptability.

[0050] refer to Figure 1 A main crucible heater 10 is installed on the outer wall of the main crucible 3, and the main crucible heater 10 is used to heat the main crucible 3. A driving member 11 is installed on the top of the main furnace body 2, and the driving member 11 can be a combination structure of a linear electric cylinder and a motor. A seed crystal rod 12 is installed on the driving end of the driving member 11, and the seed crystal rod 12 is vertically slidably arranged on the top of the main furnace body 2. The driving member 11 can drive the seed crystal rod 12 to rotate and slide up and down on the main furnace body 2. The seed crystal rod 12 extends vertically into the crystal pulling area 8 of the auxiliary crucible 4, and the crystal raw material can grow on the seed crystal rod 12 when pulling the crystal. In order to improve the structural quality of the crystal raw material, an annealing heater 13 is installed on the inner wall of the top of the main furnace body 2. The annealing heater 13 surrounds the seed crystal rod 12 and is located at one end of the main furnace body 2.

[0051] refer to Figure 1 , a feeding crucible 14 is installed on the main furnace body 2, and the feeding crucible 14 is located outside the main furnace body 2. A feeding crucible heater 15 is installed on the feeding crucible 14, and the bottom of the feeding crucible 14 is connected to a crystal feeding pipe 16, and a first high-temperature solenoid valve 17 is installed on the crystal feeding pipe 16. The crystal feeding pipe 16 passes through the main furnace body 2 and extends to the feeding area 6 of the main crucible 3. The crystal raw material can be placed in the feeding crucible 14, and the crystal raw material is heated and melted into a crystal melt by the feeding crucible heater 15. The first high-temperature solenoid valve 17 is used to control the discharge of the crystal melt, and the crystal feeding pipe 16 can transport the crystal melt in the feeding crucible 14 to the feeding area 6 of the main crucible 3 to achieve continuous feeding.

[0052] refer to Figure 1, a liquid-sealed melt injection chamber 18 is also installed on the main furnace body 2, and the liquid-sealed melt injection chamber 18 is located inside the main furnace body 2. A liquid-sealed melt injection chamber heater 19 is installed on the liquid-sealed melt injection chamber 18, and the liquid-sealed melt injection chamber heater 19 is used to heat the liquid-sealed melt injection chamber 18. The top of the liquid-sealed melt injection chamber 18 is connected to a liquid-sealed melt injection pipe 20, and the liquid-sealed melt injection pipe 20 is passed through the top of the main furnace body 2 to facilitate connection with an external liquid-sealed melt supply device. The bottom of the liquid-sealed melt injection chamber 18 is connected to a liquid-sealed melt feeding pipe 21, and the liquid-sealed melt feeding pipe 21 extends to the crystal pulling area 8, and a second high-temperature solenoid valve 22 for controlling the discharge of the liquid-sealed melt 81 is installed on the liquid-sealed melt feeding pipe 21. The liquid-sealing melt 81 can enter the liquid-sealing melt injection chamber 18 through the liquid-sealing melt injection pipe 20 to be heated, and then be transported to the crystal pulling area 8 through the liquid-sealing melt feeding pipe 21 to liquid-seal the crystal melt, thereby creating a stable growth environment for the growth of large-size crystal raw materials.

[0053] refer to Figure 1 , a dopant injection chamber 23 is also installed on the main furnace body 2, and the dopant injection chamber 23 is located in the main furnace body 2. A dopant injection chamber heater 24 is installed on the dopant injection chamber 23, and the dopant injection chamber heater 24 is used to heat the dopant injection chamber 23. The top of the dopant injection chamber 23 is connected to a dopant injection pipe 25, and the dopant injection pipe 25 is arranged on the top of the main furnace body 2 to facilitate connection with an external dopant supply device. The bottom of the dopant injection chamber 23 is connected to a dopant feeding pipe 26, and the dopant feeding pipe 26 extends to the doping area 7. A third high-temperature solenoid valve 27 is installed on the dopant feeding pipe 26, and the third high-temperature solenoid valve 27 is used to control the feeding of the dopant. The dopant can enter the dopant injection chamber 23 through the dopant injection pipe 25 for heating, and then be transported to the doping area 7 through the dopant feeding pipe 26, so as to adjust the electrical or optical properties of the crystal raw material.

[0054] At the same time, reference Figure 1 The top of the main furnace body 2 is also connected with a vacuum tube 28 and a gas charging tube 29. The vacuum tube 28 can be connected with a vacuum pump to realize vacuuming of the main furnace body 2. The gas charging tube 29 can be connected with a gas cylinder to realize gas charging of the main furnace body 2. The main furnace body 2 can be vacuumed through the vacuum tube 28, and an inert gas (helium, neon or argon) can be charged into the main furnace body 2 through the gas charging tube 29, thereby ensuring the stability of the gas in the main furnace body 2, and further ensuring the purity of the grown crystal.

[0055] refer to Figure 1, a weighing device 30 is installed on the base 1, and the weighing device 30 is located below the main crucible 3. The main crucible 3 is installed on the base 1 through the weighing device 30. The weighing device 30 is used to monitor the quality change of the crystal melt in the process of crystal raw material growth in real time. The weighing device 30 is electrically connected to a PID controller (Proportion Integration Differentiation, proportional-integral-differential controller), and the PID controller is also electrically connected to the first high-temperature solenoid valve 17, the second high-temperature solenoid valve 22 and the third high-temperature solenoid valve 27 respectively. The PID controller is also electrically connected to the main crucible heater 10, the annealing heater 13, the feed crucible heater 15, the liquid-sealed melt injection chamber heater 19, and the dopant injection chamber heater 24. The PID controller can control the opening and closing of the first high-temperature solenoid valve 17, the second high-temperature solenoid valve 22 and the third high-temperature solenoid valve 27 through the weight feedback of the weighing device 30, so as to realize the control of the addition amount of the added crystal melt, the liquid-sealed melt 81 and the dopant. The PID controller can also control the power of each of the above heaters to achieve the best crystal pulling effect.

[0056] At the same time, a rotating rod 31 is vertically rotatably penetrated at the bottom of the base 1, and the rotating rod 31 penetrates the bottom of the main crucible 3, and the end surface of the rotating rod 31 penetrating one end of the main crucible 3 does not contact the main crucible 3, thereby avoiding affecting the weighing of the main crucible 3 by the weighing device 30 when the main crucible 3 rotates. The rotating rod 31 can be externally connected to a rotating drive member, thereby driving the rotating rod 31 to rotate, thereby realizing that the main crucible 3 drives the auxiliary crucible 4 to rotate during the growth of the crystal raw material, so as to improve the crystal pulling effect.

[0057] Specifically, in the embodiment of the present application, there are three weighing devices 30, and the three weighing devices 30 are all installed on the edge of the base 1. The connecting line of the three weighing devices 30 is an acute triangle. A universal ball is installed on the weighing device 30, and the universal ball can rotate. An annular groove is provided at the bottom of the main crucible 3, and the universal ball can roll in the annular groove when rotating, so that the weighing device 30 can weigh the main crucible 3 when the main crucible 3 rotates. In other embodiments, one weighing device 30 can also be used. If there is one weighing device 30, there are at least three universal balls on the weighing device 30.

[0058] The embodiment of the present invention also provides a crystal growth method.

[0059] refer to Figure 6 , a crystal growth method comprising the following steps:

[0060] S1: Select the auxiliary crucible 4 and the fixing arm 9 according to the type of the growing crystal, and fix the auxiliary crucible 4 in the main crucible 3 through the fixing arm 9 .

[0061] S2 : adding a crystal raw material to be grown into the main crucible 3 , and heating the main crucible heater 10 to melt the crystal raw material in the main crucible 3 .

[0062] The power of the main crucible heater 10 is controlled by a PID controller, and the power p1(t) of the main crucible heater 10 is:

[0063]

[0064] Among them, err1(t) represents the deviation between the crystal growth weight and the set value, Kp1 represents the proportional band constant for controlling crystal growth, Ki1 represents the integral constant for controlling crystal growth, and Kd1 represents the differential constant for controlling crystal growth. The temperature of the main crucible 3 is sufficient to heat and melt the crystal raw material into a crystal melt.

[0065] S3: If the crystal growth requires a dopant, the dopant injection chamber heater 24 is heated, and then the heated dopant in the dopant injection chamber 23 is added to the doping area in the auxiliary crucible 4. If the crystal growth does not require a dopant, this step is omitted.

[0066] S4: heating the liquid-sealing melt injection chamber heater 19 , and then adding the heated liquid-sealing melt in the liquid-sealing melt injection chamber 18 to the crystal pulling area in the auxiliary crucible 4 .

[0067] S5: When the crystal grows on the seed rod 12 , the main crucible and the auxiliary crucible are rotated to gradually raise the seed rod 12 , and the seed rod 12 is annealed by the annealing heater 13 .

[0068] S6: the feeding amount is calculated by the PID controller and the weighing device 30 , the feeding crucible heater 15 is heated, and then the heated crystal melt in the feeding crucible 14 is added to the feeding area between the main crucible 3 and the auxiliary crucible 4 .

[0069] The power of the feeding crucible heater 15 is controlled by a PID controller, and the power p2(t) of the feeding crucible heater 15 is:

[0070]

[0071] Wherein, e2(t) represents the deviation between the actual added weight of the crystal melt and the weight of the crystal growth, Kp2 represents the proportional band constant for controlling the heating power of the feeding crucible heater 15, and K i2 represents the integral constant for controlling the heating power of the feeding crucible heater 15, and Kd2 represents the differential constant for controlling the heating power of the feeding crucible heater 15. The heating temperature of the feeding crucible should be 10-50°C higher than the crystal growth temperature.

[0072] S7: If the crystal growth requires a dopant, the dopant is added to the doping region in the auxiliary crucible 4, and the power p3(t) of the dopant injection chamber heater 24 is:

[0073]

[0074] Among them, err3(t) represents the deviation between the actual added weight of the crystal melt and the weight of the crystal growth, Kp3, K i3 , Kd3 represent the proportional band constant, integral constant, and differential constant for controlling the heating power of the dopant implantation chamber heater 24, respectively.

[0075] As described above, the above embodiments are only used to introduce the technical solution of the present invention in detail, but the description of the above embodiments is only used to help understand the method and core idea of ​​the present invention and should not be understood as limiting the present invention. Changes or substitutions that can be easily thought of by technicians in this technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A continuous feeding LEC crystal growth device, comprising a base (1), a main furnace body (2), a main crucible (3), an auxiliary crucible (4), a driving member (11) and a seed crystal rod (12), wherein the main furnace body (2), the main crucible (3) and the linear driving member (11) are all mounted on the base (1), the main crucible (3) is located in the main furnace body (2), the auxiliary crucible (4) is mounted in the main crucible (3) and is connected to the main crucible (3), the seed crystal rod (12) is slidably arranged on the main furnace body (2) and the lower end is located in the auxiliary crucible (4), the driving end of the driving member (11) is connected to the seed crystal rod (12) and is used to drive the seed crystal rod (12) to rotate and move up and down; the main crucible (3) is mounted with a main crucible heater (10), characterized in that The auxiliary crucible (4) is a single-layer or double-layer auxiliary crucible (4), and further comprises: A feeding crucible (14) is mounted on the main furnace body (2), a feeding crucible heater (15) is mounted on the feeding crucible (14), a crystal feeding pipe (16) extending to the feeding area (6) of the main crucible (3) is connected to the bottom of the feeding crucible (14), and a first high-temperature electromagnetic valve (17) is mounted on the crystal feeding pipe (16); a dopant injection chamber (23) is mounted on the main furnace body (2), and a dopant injection chamber heater is mounted on the dopant injection chamber (23) (24), the bottom of the dopant injection chamber (23) is connected to a dopant feeding pipe (26), and a third high-temperature solenoid valve (27) is installed on the dopant feeding pipe (26); a weighing device (30) is installed on the base (1), and the main crucible (3) is installed on the base (1) through the weighing device (30), and the weighing device (30) is electrically connected to a PID controller, and the PID controller is electrically connected to the first high-temperature solenoid valve (17) and the third high-temperature solenoid valve (27), respectively.

2. The continuous feeding LEC crystal growth device according to claim 1, characterized in that: A rotating rod (31) is rotatably penetrated through the bottom of the base (1); the rotating rod (31) is penetrated through the bottom of the main crucible (3) and the end face thereof does not contact the main crucible (3); the rotating rod (31) is used to rotate the main crucible (3); a universal ball is mounted on each weighing device (30); an annular groove is provided at the bottom of the main crucible (3), and the universal ball is located in the annular groove.

3. The continuous feeding LEC crystal growth device as claimed in claim 2, characterized in that: The main furnace body (2) is provided with a liquid-sealed melt injection chamber (18), a liquid-sealed melt injection chamber (18) heater is provided on the liquid-sealed melt injection chamber (18), the bottom of the liquid-sealed melt injection chamber (18) is connected to a liquid-sealed melt feeding pipe (21), and a second high-temperature solenoid valve (22) electrically connected to a PID controller is provided on the liquid-sealed melt feeding pipe (21).

4. The continuous feeding LEC crystal growth device according to any one of claims 1 to 3, characterized in that: An annealing heater (13) is installed on the inner wall of the top of the main furnace body (2).

5. The continuous feeding LEC crystal growth device as claimed in claim 4, characterized in that: The main crucible (3) and the auxiliary crucible (4) are fixed by a fixing arm (9).

6. The continuous feeding LEC crystal growth device according to claim 4, characterized in that: The main furnace body (2) is connected with a vacuum tube (28) and an air charging tube (29).

7. A crystal growth method, characterized in that: The following steps are involved: S1: selecting a secondary crucible (4) and a fixed arm (9) according to the type of the growing crystal, and fixing the secondary crucible (4) in the main crucible (3) by means of the fixed arm (9); S2: adding the crystal raw material to be grown into the main crucible (3), heating the main crucible heater (10), and causing the crystal raw material to melt in the main crucible (3); S3: If the crystal growth requires a dopant, the dopant injection chamber heater (24) is heated, and then the heated dopant in the dopant injection chamber (23) is added to the doping area (7) in the auxiliary crucible (4). If the crystal growth does not require a dopant, this step is omitted; S4: heating a heater of the liquid-sealed melt injection chamber (18), and then adding the heated liquid-sealed melt (81) in the liquid-sealed melt injection chamber (18) to the crystal pulling zone (8) in the auxiliary crucible (4); S5: when the crystal grows on the seed crystal rod (12), the main crucible (3) and the auxiliary crucible (4) are rotated, the seed crystal rod (12) is rotated and gradually raised, and the seed crystal rod (12) is annealed by the annealing heater (13); S6: calculating the amount of feed through a PID controller and a weighing device (30), heating a feed crucible heater (15), and then adding the heated crystal melt in the feed crucible (14) to a feed area (6) between the main crucible (3) and the auxiliary crucible (4); S7: If the crystal growth requires a dopant, the dopant replenishment amount is calculated based on the weight measured by the weigher (30) by the PID controller, and the dopant is added to the doping area (7) in the sub-crucible (4).

8. The crystal growth method according to claim 7, characterized in that The power p1(t) of the main crucible heater (10) is: Among them, err1(t) represents the deviation between the crystal growth weight and the set value, Kp1, K i1 , Kd1 represent the proportional band constant, integral constant and differential constant that control crystal growth respectively.

9. The crystal growth method according to claim 7, characterized in that: The power p2(t) of the feeding crucible heater (15) is: Among them, err2(t) represents the deviation between the actual added weight of the crystal melt and the weight of the crystal growth, Kp2, K i2 , Kd2 represent respectively the proportional band constant, integral constant and differential constant for controlling the heating power of the feeding crucible heater (15).

10. The crystal growth method according to claim 7, characterized in that The power p3(t) of the dopant implantation chamber heater (24) is: Among them, err3(t) represents the deviation between the actual added weight of the crystal melt and the weight of the crystal growth, Kp3, K i3 , Kd3 represent respectively the proportional band constant, integral constant and differential constant for controlling the heating power of the dopant injection chamber heater (24).

Images