Liquid phase growth equipment and liquid phase growth method of semiconductor single crystal

Abstract

The invention discloses liquid phase growth equipment and a liquid phase growth method for semiconductor single crystals, and belongs to the technical field of semiconductor preparation. The equipment comprises a crucible capable of containing a raw material solution, a plurality of protrusions are arranged on the inner wall of the crucible, and the protrusions are arranged at equal intervals in the circumferential direction of the inner wall; a crystal support shaft capable of supporting the semiconductor single crystal; and the rotating mechanism is used for driving the crucible to rotate. In the crystal growth period, the crucible is driven by the rotating mechanism to rotate, and the bulges are arranged on the inner wall of the crucible, so that bubbles are more easily generated near the inner wall of the crucible than near the rotating shaft, the proportion of the bubbles reaching the surface of the semiconductor single crystal is reduced, the bubbles are prevented from entering the crystal, and the crystallization quality of the crystal is improved.

Description

Technical Field

[0001] The present application relates to a liquid phase growth device and a liquid phase growth method for a semiconductor single crystal, and belongs to the technical field of semiconductor preparation. Background Art

[0002] For example, in the prior art such as WO2014192573A1, when a semiconductor single crystal is produced by a liquid phase method, a seed crystal is immersed in a raw material solution, so that the raw material dissolved in the solution around the seed crystal is in a supersaturated state, and crystals are precipitated on the surface of the seed crystal.

[0003] In the crystal growth of the liquid phase method, due to temperature fluctuations and turbulence, the inert gas dissolved in the raw material solution sometimes turns into bubbles, and the bubbles generated rise under the action of buoyancy and reach the liquid surface. As a result, part of the bubbles will adhere to the surface of the growing semiconductor single crystal, and sometimes they will be absorbed by the crystal. Once the bubbles enter the crystal, they will cause defects such as voids, stress concentration, TSD (Threading Screw Dislocation), and cracks. Summary of the invention

[0004] In order to solve the above problems, a liquid phase growth device and a liquid phase growth method of a semiconductor single crystal are provided. During the crystal growth period, the crucible is driven to rotate by a rotating mechanism and a protrusion is provided on the inner wall of the crucible, so that bubbles are more likely to be generated near the inner wall of the crucible than near the rotation axis, thereby reducing the proportion of bubbles reaching the surface of the semiconductor single crystal, thereby inhibiting the bubbles from entering the crystal and improving the crystallization quality of the crystal.

[0005] According to one aspect of the present application, there is provided a liquid phase growth device for a semiconductor single crystal, comprising:

[0006] A crucible capable of containing a raw material solution, wherein a plurality of protrusions are arranged on the inner wall of the crucible, and the plurality of protrusions are equally spaced from each other in the circumferential direction of the inner wall;

[0007] a crystal support shaft capable of supporting the semiconductor single crystal;

[0008] A rotating mechanism is used to drive the crucible to rotate.

[0009] Optionally, in a direction perpendicular to the bottom surface of the crucible, the density of the protrusions on the upper portion of the crucible is greater than the density of the protrusions on the lower portion of the crucible.

[0010] Optionally, the interval between adjacent protrusions is 1 to 5 mm.

[0011] Optionally, the height of the protrusion from the inner wall surface of the crucible is 0.2 to 2 mm;

[0012] Preferably, the height of the protrusion located at the upper part of the crucible from the inner wall surface of the crucible is greater than the height of the protrusion located at the lower part of the crucible from the inner wall surface of the crucible.

[0013] Optionally, a vibration mechanism is further included, and the vibration mechanism is used to drive the crucible to vibrate.

[0014] Optionally, the rotating mechanism is disposed below the crucible, and further comprises a crucible shaft rotatable around a central axis of the crucible, and the vibrating mechanism drives the crucible to vibrate via the crucible shaft.

[0015] According to another aspect of the present application, a method for liquid phase growth of a semiconductor single crystal is provided, which is performed using any of the liquid phase growth equipment for a semiconductor single crystal described above, wherein the crucible is driven to rotate by a rotating mechanism during at least a portion of the growth period of the semiconductor single crystal.

[0016] Optionally, the rotating mechanism drives the crucible to rotate, so that a first period of rotating the crucible at a first rotation speed and a second period of rotating the crucible at a second rotation speed higher than the first rotation speed are performed alternately.

[0017] Optionally, the first rotation speed is lower than 10 rpm, preferably 0-5 rpm.

[0018] Optionally, the second rotation speed is above 10 rpm, preferably above 50 rpm.

[0019] Optionally, the rotating mechanism can drive the crucible to rotate clockwise and counterclockwise;

[0020] The crystal growth period includes a period of repeating in the order of a first period of clockwise rotation, a second period of clockwise rotation, a first period of counterclockwise rotation, and a second period of counterclockwise rotation; or

[0021] The crystal growth period includes a period of repeating in the order of clockwise rotation for the second period, clockwise rotation for the first period, counterclockwise rotation for the second period, and counterclockwise rotation for the first period.

[0022] Optionally, the semiconductor single crystal liquid phase growth device further comprises a vibration mechanism, wherein the vibration mechanism drives the crucible to vibrate during at least a portion of the growth period of the semiconductor single crystal;

[0023] Preferably, the vibration amplitude of the vibration mechanism is 50-500 μm, and the vibration frequency is 10-50 KHz.

[0024] The beneficial effects of this application include but are not limited to:

[0025] 1. When a semiconductor single crystal is prepared by using the semiconductor single crystal liquid phase growth device of the present application, the crucible is rotated by a rotating mechanism, so that the raw material solution can generate a rotating flow centered on the rotation axis, and the flow rate distribution of the rotating flow is the largest near the inner wall and the smallest near the rotation axis. Based on the mechanism that the greater the flow rate, the lower the hydraulic pressure, and therefore the easier it is to form bubbles, by periodically rotating the crucible at a speed of 10 rpm or more, the flow rate of the raw material solution near the inner wall can be appropriately increased, so that bubbles can be preferentially formed near the inner wall rather than near the rotation axis, thereby reducing the proportion of bubbles reaching the surface of the semiconductor single crystal, and the speed of the crucible rotation can be arbitrarily adjusted in conjunction with different growth processes.

[0026] 2. The liquid phase growth equipment for semiconductor single crystals of the present application can generate local turbulence near the inner wall by means of a plurality of protrusions arranged on the inner wall, thereby making it easier for bubbles to form near the inner wall. Therefore, more bubbles can be precipitated on the inner wall side compared to the rotation axis side, thereby reducing the proportion of bubbles reaching the surface of the semiconductor single crystal, thereby inhibiting the bubbles from entering the crystal, significantly removing bubbles and inclusions in the liquid phase semiconductor single crystal, and improving the crystallization quality of the crystal. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0028] Figure 1 is a schematic structural cross-sectional view of the crystal growth system 1;

[0029] Figure 2 is an enlarged cross-sectional view near the crucible 10;

[0030] Figure 3 yes Figure 2 A cross-sectional view taken along line III-III;

[0031] Figure 4 yes Figure 2 A cross-sectional view taken along line IV-IV of FIG.

[0032] Figure 5 is a flow chart illustrating a method for growing a silicon carbide single crystal;

[0033] Figure 6 is a cross-sectional view showing a conventional crystal growth method;

[0034] Figure 7 is a cross-sectional view illustrating a crystal growth method according to the technology herein;

[0035] Figure 8 yes Figure 7A cross-sectional view of line VIII-VIII;

[0036] List of parts and reference numerals:

[0037] 1. Crystal growth system; 2. Control device; 3. Crystal growth device; 5. Chamber; 10. Crucible; 10i. Inner wall; 10p. Protrusion; 12. Crucible axis; 13. Crystal support axis; 14. High-frequency coil; 16. Seed crystal; 17. Solution; 18. Growing crystal; 19. Rotating part; 20. Driving part; 21. Vibration mechanism; 31. Operation control component; 32. Vibration control component; CA, rotating axis; BU, bubble. DETAILED DESCRIPTION

[0038] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0039] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0040] Unless otherwise specified, the methods used in the embodiments of the present application are conventional methods in the prior art.

[0041] Example 1

[0042] <Configuration of crystal growth system 1>

[0043] Figure 1 1 shows a schematic cross-sectional view of the crystal growth system 1. The crystal growth system 1 includes a control device 2 and a crystal growth device 3. The crystal growth device 3 is a device capable of growing various semiconductor single crystals using a liquid phase method. In this embodiment, the growth of a silicon carbide (SiC) single crystal will be described.

[0044] The crystal growth device 3 mainly includes a chamber 5, a crucible 10, a crucible table 11, a crucible shaft 12, a crystal support shaft 13, a high-frequency coil 14, a rotating part 19, a driving part 20, and a vibration mechanism 21. The chamber 5 has an outer surface outside a cylinder, and stores the high-frequency coil 14, the crucible 10, and the crucible table 11. The crucible table 11 is a table for mounting the crucible 10, and the crucible shaft 12 is a shaft that rotatably supports the crucible 10 and the crucible table 11, and the crucible shaft 12 has a rotation axis CA. The rotating part 19 is arranged below the crucible 10, and the rotating part 19 rotates the crucible shaft 12 around the rotation axis CA. The vibration mechanism 21 is arranged on the crucible shaft 12, and the vibration mechanism 21 is a mechanism for applying vibration to the crucible shaft 12, and the vibration mechanism 21 will be described later. The high-frequency coil 14 receives power from a power supply device (not shown) and induction heats the crucible 10.

[0045] A crystal support shaft 13 is disposed above the crucible 10, and a seed crystal 16 and a growth crystal 18 are fixed below the crystal support shaft 13. In this embodiment, the seed crystal 16 and the growth crystal 18 are single crystals of silicon carbide. The bottom of the crystal support shaft 13 extends into the interior of the crucible 10, and the crystal support shaft 13 has a rotation axis CA. The driving unit 20 rotates the crystal support shaft 13 around the rotation axis CA and moves in the vertical direction ( Figure 1 Move in the Z-axis direction).

[0046] The control device 2 includes an operation control component 31 and a vibration control component 32. The operation control component 31 is a component for controlling the operation of the rotating component 19 and the driving component 20, and the vibration control component 32 is a component for controlling the vibration of the vibration mechanism 21. For example, the control device 2 may be a PC having a CPU or a memory.

[0047] <Structure of Crucible 10>

[0048] Figure 2 An enlarged cross-sectional view of the vicinity of the crucible 10 is shown. The crucible 10 has a cylindrical shape centered on the rotation axis CA, and contains a solution 17 in the crucible 10, which is a silicon-based solution. The crucible 10 is inductively self-heated by a high-frequency coil 14, providing a heat source for the solution 17 during crystal growth. The crucible 10 is made of a carbon material (graphite), so carbon atoms can be supplied from the crucible 10 to the solution 17.

[0049] Figure 3 express Figure 2 The cross-sectional view along line III-III, Figure 4 It also shows Figure 2 The cross-sectional view along line IV-IV, Figure 3 and Figure 4 Each of them is a cross-sectional view through the protrusion 10p. Figure 3 is the upper cross section of the crucible 10, Figure 4 A plurality of protrusions 10p are arranged on the inner wall 10i of the crucible 10, and the shapes of the protrusions 10p can be various, such as cones, pyramids, cylinders, prisms, hemispheres, etc. In this embodiment, the shape of the protrusions 10p is a cone.

[0050] The method of forming the plurality of protrusions 10p may be various. For example, when the crucible 10 is formed, it may be formed integrally with the inner wall 10i. In addition, for example, the protrusions 10p formed to be separated from the crucible 10 may be fixed to the inner wall 10i. In the present embodiment, the plurality of protrusions 10p are formed integrally with the inner wall 10i. Note that the protrusions 10p formed integrally can be formed by a well-known crucible manufacturing method, and therefore a detailed description thereof is omitted.

[0051] like Figure 3 and Figure 4 As shown, a plurality of protrusions 10p are arranged at equal intervals from each other in the circumferential direction of the inner wall 10i. Figure 3 As shown in FIG. 1 , the intervals D1 between adjacent protrusions 10p are all the same. Figure 4 As shown, the intervals D2 between adjacent protrusions 10p are all the same. Therefore, the heat capacity of the crucible 10 can be made uniform in the circumferential direction, so that the temperature distribution when the crucible 10 is heated is rotationally symmetric with respect to the rotation axis CA.

[0052] As one embodiment, the interval D1 on the upper side is smaller than the interval D2 on the lower side. That is, the arrangement density of the plurality of protrusions 10p is higher on the upper side than on the lower side. As described later, bubbles BU are more likely to precipitate on the upper side than on the lower side.

[0053] The height H of the plurality of protrusions 10p from the surface of the inner wall 10i may be appropriately determined so as to balance the efficiency of forming the bubbles BU and the efficiency of growing the crystals. That is, if the height H of the protrusions 10p is too low, the effect of forming the bubbles BU is reduced. On the other hand, if the height H of the protrusions 10p is too high, the disturbed area of ​​the solution 17 expands from the inner wall 10i to the center side, and the crystal growth rate may decrease. For example, the height H may be in the range of 0.2 to 2 mm.

[0054] The height H of the plurality of protrusions 10p may vary in the vertical direction of the crucible 10. For example, the height H of the upper side may be higher than that of the lower side. In addition, the height H of the central portion may also be higher than that of the lower side and the upper side.

[0055] The intervals between the plurality of protrusions 10p may be appropriately determined in a manner that balances the efficiency of forming the bubbles BU and the processing cost of the protrusions 10p. That is, if the intervals are too large, the effect of forming the bubbles BU will be reduced. On the other hand, if the intervals are too small, the difficulty of processing the protrusions 10p increases, the manufacturing cost of the crucible 10 increases, or the production yield rate decreases. For example, the intervals may be in the range of 1 to 5 mm.

[0056] Note that the protrusions 10p do not increase the amount of polycrystals precipitated on the inner wall 10i. Since the crucible 10 is heated by the high frequency coil 14, the inner wall 10i is hotter than the center of the solution 17, and polycrystals are less likely to precipitate.

[0057] <Crystal Growth Method>

[0058] use Figure 5The flowchart of the invention illustrates a method for growing a single crystal of silicon carbide by a liquid phase method. In step S10, a preparation process is performed. Specifically, polycrystalline silicon and a solvent are placed in a crucible 10. The solvent can be one or a combination of two or more of Ti, Cr, Sc, Ni, Al, Co, Mn, Mg, Ge, As, Dy, Y, Nb, Nd and Fe. The amount of solvent added accounts for 30%-70% of the total molar number in the solution. The crucible 10 is arranged on a crucible table 11, a seed crystal 16 is fixed on a crystal support shaft 13, the seed crystal 16 is arranged at a predetermined position inside the crucible 10, and the chamber 5 is sealed.

[0059] In step S20, a heating process is performed: specifically, the internal atmosphere of the chamber 5 is vacuumed, and then filled with an inert gas (any one of helium, neon or argon), and the temperature in the crucible 10 is heated by the high-frequency coil 14 to reach a predetermined growth temperature. The growth temperature of silicon carbide is generally in the range of 1700 to 2000° C. In this embodiment, the growth temperature is set to 1800° C., which causes the polysilicon and the flux to melt and form a solution 17.

[0060] In step S40 , a seed crystal contact process is performed: specifically, after the growth temperature is reached, the position of the seed crystal 16 is lowered to make it contact with the solution 17 .

[0061] In steps S50 to S80, a growth process is performed: specifically, the drive unit 20 lifts the seed crystal 16 upward at a constant speed based on the crystal growth rate. The rotating mechanism 19 also controls the rotation of the crucible 10 so that the low-speed rotation period and the high-speed rotation period come alternately. The low-speed rotation period is a period in which the crucible 10 is rotated at a first rotation speed (S50, S70). The high-speed rotation period is a period in which the crucible 10 is rotated at a second rotation speed higher than the first rotation speed (S60 and S80). The first rotation speed is lower than 10rpm, and preferably, the first rotation speed is 0 to 5rpm. The second rotation speed is above 10rpm, and preferably, the second rotation speed is above 50rpm. A specific description will be given below.

[0062] The rotating mechanism 19 repeats the clockwise low-speed rotation period (S50), the clockwise high-speed rotation period (S60), the counterclockwise low-speed rotation period (S70), and the counterclockwise high-speed rotation period (S80) in this order. Figure 3 As shown, the clockwise rotation period (S50 and S60) is a period in which the crucible 10 rotates in the clockwise rotation direction R1, and the counterclockwise rotation period (S70 and S80) is a period in which the crucible 10 rotates in the counterclockwise rotation direction R2. The periods S50 to S80 are repeated periodically, and the length and period conditions of each period can be variously set according to the crystal growth state.

[0063] A specific example of this embodiment is described as follows: in step S50, the crucible 10 is rotated in the clockwise direction R1 at a first rotation speed, and when a first predetermined time (eg, 0.1 to 1 hour) has passed, the process proceeds to step S60.

[0064] In step S60, first, the first rotation speed is accelerated to the second rotation speed, and the time required for acceleration can be, for example, 0.1 to 1 minute. Then, the state of rotating in the rotation direction R1 at the second rotation speed is maintained for a second predetermined time (for example, 1 to 5 minutes). After the second predetermined time, the crucible 10 is reversely rotated in the counterclockwise rotation direction R2, thereby decelerating from the second rotation speed to zero speed, and the time required for deceleration can be, for example, 0.1 to 1 minute. When the deceleration is completed, the process is transferred to step S70.

[0065] In step S70 , the crucible 10 is rotated in the counterclockwise direction R2 at a first rotation speed, and when a first predetermined time has passed, the process proceeds to step S80 .

[0066] In step S80, the first rotation speed is accelerated to the second rotation speed. Then, the state of rotating in the rotation direction R2 at the second rotation speed is maintained for a second predetermined time. After the second predetermined time, the crucible 10 is reversely rotated in the clockwise rotation direction R1 and decelerated from the second rotation speed to zero speed. When the deceleration is completed, the process is transferred to step S90.

[0067] In step S90, it is determined whether the amount of crystal growth has reached a specified amount. If the determination is negative (S90: No), the process returns to step S50 and the crystal growth continues. On the other hand, in the case of a positive determination (S90: Yes), the process proceeds to step S100. In step S100, a cooling process is performed. Specifically, after the growing crystal 18 is raised and removed from the liquid surface, the heating component is turned off. In step S110, a furnace opening process is performed. Specifically, the chamber 5 is opened and the crystal is taken out.

[0068] <Question>

[0069] use Figure 6 The problems existing in the prior art are explained. Figure 6 1 is a cross-sectional view of a conventional liquid phase crystal growth method. In the liquid phase crystal growth method, due to factors such as temperature fluctuations and turbulence, the inert gas dissolved in the solution 17 sometimes forms bubbles BU. Figure 6In the figure, bubbles BU are shown as white circles in simulation, and the generated bubbles BU rise upward (in the +z direction) by buoyancy and reach the liquid surface 17s. In the conventional crystal growth method, a part of the bubbles BU reaching the liquid surface 17s sometimes adheres to the surface 18s of the growing crystal 18 (see region RE1), and as a result, the bubbles BU are sometimes wrapped inside the growing crystal 18 (see region RE2). If the bubbles BU are wrapped in the growing crystal 18, cracks, stress concentration, TSD, and voids may occur.

[0070] <Effect>

[0071] Reference Figure 7 Describe the technical effects of this application. Figure 7 is with Figure 6 The same cross-sectional view, Figure 8 yes Figure 7 The technology of the present specification includes a high-speed rotation period (S60) in which the crucible 10 is rotated in the clockwise rotation direction R1 at a rotation speed of 10 rpm or more. In the high-speed rotation period, Figure 8 As shown, a rotating flow RF around the rotation axis CA can be generated in the solution 17, and the flow velocity distribution of the rotating flow RF is the largest near the inner wall 10i and the smallest near the rotation axis CA, and since the greater the flow velocity, the lower the hydraulic pressure, bubbles BU can be easily formed. Figure 7 As shown, bubbles BU can be preferentially formed in the peripheral area A2 near the inner wall 10i, compared with the central area A1 near the rotation axis CA, and the central area A1 is an area where the growing crystal 18 is located above it (in the +z direction) and the liquid surface 17s is blocked by the growing crystal 18. On the other hand, the peripheral area A2 is an area where there is no growing crystal 18 above it, and therefore the liquid surface 17s is a free liquid surface, that is, the bubbles BU generated in the peripheral area A2 will discharge the solution 17 from the free liquid surface area of ​​the liquid surface 17S, and will not adhere to the growing crystal surface 18s.

[0072] Therefore, in the technology of the present specification, more bubbles BU can be precipitated in the peripheral area A2 compared with the central area A1, so the ratio of bubbles BU attached to the surface 18s can be reduced, and thus the bubbles BU can be suppressed from being wrapped in the growing crystal 18. In addition, when the crucible 10 is rotated in the counterclockwise direction R2 at a rotation speed of 10 rpm or more (S80), the same effect is obtained.

[0073] In the technology of the present specification, the plurality of protrusions 10p arranged on the inner wall 10i can generate local turbulence near the inner wall 10i. Since turbulence can form a low-pressure area, more bubble BU nucleation points (tiny points in the liquid that promote the formation of bubbles BU) can be generated near the inner wall 10i compared to the vicinity of the rotation axis CA. As a result, more bubbles BU can be precipitated in the peripheral area A2 compared to the central area A1, so the proportion of bubbles BU attached to the surface 18s can be reduced.

[0074] During the period when the bubbles BU generated in the peripheral area A2 move to the liquid surface 17s, the bubbles BU move to the central area A1 due to the flow of the solution 17, and sometimes adhere to the surface 18s. The longer the moving distance of the bubbles BU (that is, the lower the position of the bubbles BU), the greater the probability of such a situation. Therefore, in the technology of the present invention, the arrangement density of the protrusions 10p is at the top (see Figure 3 ) is higher than the bottom (see Figure 4 ). As a result, air bubbles BU are more likely to be precipitated on the upper side than on the lower side, so that the probability of air bubbles BU adhering to the surface 18s can be further reduced.

[0075] The liquid phase growth method of the semiconductor single crystal can produce silicon carbide crystals larger than 4 inches, and the density of bubbles or voids in the 2 / 3 radius area of ​​the silicon carbide crystal is less than 0.1 cm -2 The diameter of a single bubble or cavity is less than 10 μm, and the density of bubbles or cavities outside the 2 / 3 radius area is less than 1 cm -2 , the diameter of a single bubble or cavity is less than 100 μm; and the TSD density is less than 100 cm -2 , BPD density is less than 200cm -2 The absolute stress value in the radial direction of the crystal is -20 to 40 MPa, and the absolute stress value in the axial direction is -20 to 40 MPa.

[0076] Example 2

[0077] The difference between this embodiment and the first embodiment is that the present embodiment further uses a vibration mechanism 21. Hereinafter, only the differences from the first embodiment will be described.

[0078] The vibration mechanism 21 is disposed on the crucible shaft 12 . The vibration mechanism 21 is a mechanism for applying vibration to the crucible 10 via the crucible shaft 12 . The vibration mechanism 21 may be of various types, for example, an ultrasonic vibration device.

[0079] The vibration mechanism 21 vibrates the crucible 10 during at least some of the growth cycles of the growing crystal 18, which allows the oscillation to be transmitted to the solution 17 located near the inner wall 10i, further promoting the precipitation of bubbles BU near the inner wall 10i due to the effect of the cavitation phenomenon.

[0080] The period of time during which vibration is applied by the vibration mechanism 21 may be different. For example, vibration may be applied during a portion or the entire period of the high rotation period (S60 and S80). Alternatively, vibration may be applied during the entire growth period of the crystal.

[0081] The amplitude or frequency of the vibration generated by the vibration mechanism 21 can be appropriately determined to balance the efficiency of the formation of the bubbles BU and the stability of the crystal growth. That is, if the amplitude is too small, it is difficult for the bubbles BU to precipitate from the vicinity of the inner wall 10i; on the other hand, if the amplitude is too large, the vibration wave will propagate from the inner wall 10i to the crystal growth area on the central side, which may have an adverse effect on the crystal growth. For example, the amplitude of the vibration can be in the range of 50 to 500 μm, and the frequency can be in the range of 10 to 50 kHz.

[0082] <Modification>

[0083] In this embodiment, the method of changing the rotation direction when switching from the high-speed rotation period to the low-speed rotation period is described, but it is not limited to this method. When switching from the low-speed rotation period to the high-speed rotation period, the rotation direction can be switched. In this case, the rotation of the crucible 10 can be controlled so that the clockwise high-speed rotation period, the clockwise low-speed rotation period, the counterclockwise high-speed rotation period, and the counterclockwise low-speed rotation period are repeated in this order. In addition, for example, the rotation direction can also be switched at any timing during the low-speed rotation period.

[0084] Although the method of switching alternately between the low-speed rotation period and the high-speed rotation period has been described, the invention is not limited to this method. For example, the crucible 10 may be rotated at a high speed throughout the crystal growth period.

[0085] The crucible 10 and the crucible shaft 12 may be connected in various ways. For example, the upper end of the crucible shaft 12 may be directly fixed to the bottom surface of the crucible 10 .

[0086] In this embodiment, the case of growing silicon carbide crystals is described, but the invention is not limited to this form. The technology of this specification is applicable to all crystals that can be grown by solution method. For example, the technology of this specification can be applied to single crystal silicon (Si), sapphire (α-Al2O3), tellurium dioxide (TeO2), bismuth germanate (Bi4Ge3O 12 ) and other crystal growth systems.

[0087] The low rotation period is an example of the first period. The high rotation period is an example of the second period.

[0088] The above describes the implementation methods in detail, but these are only examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the above examples. The technical elements described in this article or the drawings exert technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of application. The technology shown here or in the drawings achieves multiple purposes at the same time, and achieving one of the purposes itself has technical applicability. Any modifications, equivalent substitutions, improvements, etc. made within the technical ideas and principles of this application should be included in the scope of protection of this application.

Claims

1. A liquid phase growth device for semiconductor single crystals, characterized in that: include: A crucible capable of containing a raw material solution, wherein a plurality of protrusions are arranged on the inner wall of the crucible, and the plurality of protrusions are equally spaced from each other in the circumferential direction of the inner wall; a crystal support shaft capable of supporting the semiconductor single crystal; A rotating mechanism is used to drive the crucible to rotate.

2. The semiconductor single crystal liquid phase growth device according to claim 1, characterized in that: In a direction perpendicular to the bottom surface of the crucible, the density of the protrusions on the upper part of the crucible is greater than the density of the protrusions on the lower part of the crucible.

3. The semiconductor single crystal liquid phase growth device according to claim 1, characterized in that: The spacing between adjacent protrusions is 1 to 5 mm.

4. The semiconductor single crystal liquid phase growth device according to claim 1, characterized in that: The height of the protrusion from the inner wall surface of the crucible is 0.2 to 2 mm; Preferably, the height of the protrusion located at the upper part of the crucible from the inner wall surface of the crucible is greater than the height of the protrusion located at the lower part of the crucible from the inner wall surface of the crucible.

5. The semiconductor single crystal liquid phase growth device according to any one of claims 1 to 4, characterized in that: It also includes a vibration mechanism, and the vibration mechanism is used to drive the crucible to vibrate.

6. The semiconductor single crystal liquid phase growth device according to claim 5, characterized in that: The rotating mechanism is arranged below the crucible and further comprises a crucible shaft which can rotate around the central axis of the crucible. The vibrating mechanism drives the crucible to vibrate via the crucible shaft.

7. A method for liquid phase growth of a semiconductor single crystal, which is carried out using the semiconductor single crystal liquid phase growth device according to any one of claims 1 to 6, characterized in that: The crucible is rotated by a rotating mechanism during at least a portion of the semiconductor single crystal growth period.

8. The method for growing a semiconductor single crystal in liquid phase according to claim 7, characterized in that: The rotating mechanism drives the crucible to rotate, so that a first period of rotating the crucible at a first rotation speed and a second period of rotating the crucible at a second rotation speed higher than the first rotation speed are performed alternately.

9. The method for growing a semiconductor single crystal in liquid phase according to claim 8, characterized in that: The rotating mechanism can drive the crucible to rotate clockwise and counterclockwise; The crystal growth period includes a period of repeating in the order of a first period of clockwise rotation, a second period of clockwise rotation, a first period of counterclockwise rotation, and a second period of counterclockwise rotation; or The crystal growth period includes a period of repeating in the order of clockwise rotation for the second period, clockwise rotation for the first period, counterclockwise rotation for the second period, and counterclockwise rotation for the first period.

10. The method for growing a semiconductor single crystal in liquid phase according to claim 7, characterized in that: The semiconductor single crystal liquid phase growth apparatus further comprises a vibration mechanism, wherein the vibration mechanism drives the crucible to vibrate during at least a portion of the growth period of the semiconductor single crystal; Preferably, the vibration amplitude of the vibration mechanism is 50-500 μm, and the vibration frequency is 10-50 KHz.

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