Silicon carbide crystal growth device and control method

Abstract

This invention discloses a silicon carbide crystal growth apparatus and control method. The silicon carbide crystal growth apparatus includes: a quartz cover; a first crucible and a second crucible. The first crucible has a growth chamber open at one end, and a graphite support for placing a seed crystal is provided inside the growth chamber. The seed crystal and the graphite support divide the growth chamber into a first chamber and a second chamber. A protective component is provided inside the first chamber. The second crucible has a third chamber open at the top. A driving module is used to drive the first crucible to rotate around a preset straight line K between a first position and a second position. In the first position, the second chamber is located directly above the first chamber, and the silicon surface of the seed crystal is opposite to and facing downwards from a circular through-hole. In the second position, the second chamber is connected to the third chamber, and the carbon surface of the seed crystal faces downwards. According to the silicon carbide crystal growth apparatus of this invention, seed crystal self-adhesion can be achieved, and continuous growth of four-inch and six-inch silicon carbide crystals can be achieved simultaneously.

Description

Technical Field

[0001] This invention relates to the field of crystal growth, and in particular to a silicon carbide crystal growth apparatus and control method. Background Technology

[0002] Silicon carbide (SiC) is a third-generation semiconductor material developed after silicon (the first-generation semiconductor material) and gallium arsenide (the second-generation semiconductor material). Compared with traditional semiconductor materials represented by silicon and gallium arsenide, it has characteristics such as wide bandgap, high critical breakdown electric field, high thermal conductivity, low dielectric constant, and high carrier saturation concentration. It can be applied in high-temperature and radiation-resistant fields such as aerospace exploration, nuclear energy exploration and development, satellites, and automotive engines. However, regardless of the method used to prepare silicon carbide crystals, there are problems such as slow crystal growth rate and low production capacity, making silicon carbide wafers extremely expensive. Therefore, improving the production efficiency of silicon carbide crystals is key to reducing production costs.

[0003] Furthermore, in related technologies, seed crystals and graphite caps are generally bonded together by curing and sintering carbon adhesives and carbon-containing organic materials, which can easily lead to uneven adhesive application and low seed crystal bonding efficiency, affecting crystal growth quality and production efficiency. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention provides a silicon carbide crystal growth apparatus that can achieve self-adhesion of seed crystals and simultaneously achieve continuous growth of four-inch and six-inch silicon carbide crystals.

[0005] The present invention also proposes a control method for a silicon carbide crystal growth apparatus.

[0006] A silicon carbide crystal growth apparatus according to an embodiment of the present invention includes: a quartz cover defining a receiving space; a first crucible and a second crucible, both located within the receiving space, the first crucible being positioned above the second crucible; the first crucible having a growth chamber open at one end; a graphite support for placing a seed crystal within the growth chamber; the graphite support being annular and having a circular through-hole defined in its center; multiple vent holes being provided at corresponding portions of the graphite support and the seed crystal in the vertical direction; the seed crystal and the graphite support dividing the growth chamber into a first chamber and a second chamber; a protective component being provided within the first chamber, the protective component dividing the first chamber into a first sub-chamber and a second sub-chamber; the protective component being configured to be gas-only. The second sub-chamber is located on the side of the first sub-chamber opposite to the seed crystal, and contains first silicon carbide powder. The second crucible has a third chamber with an open top, and contains second silicon carbide powder. A driving module is connected to the first crucible and is used to drive the first crucible to rotate around a preset straight line K between a first position and a second position. In the first position, the second chamber is located directly above the first chamber, with the silicon surface of the seed crystal facing downwards and the carbon surface of the seed crystal facing upwards. In the second position, the second chamber is located directly below the first chamber, and is connected to the third chamber, with the carbon surface of the seed crystal facing downwards and the silicon surface of the seed crystal facing upwards.

[0007] According to an embodiment of the silicon carbide crystal growth apparatus of the present invention, a first crucible and a second crucible are arranged inside a quartz jar, and a driving module is adapted to drive the first crucible to rotate around a preset straight line K between a first position and a second position. Before crystal growth, the driving module can first control the first crucible to rotate to the first position, and then place the seed crystal on the graphite support of the first crucible. During the crystal growth process, the first crucible can be controlled to remain in the first position, and the first crucible can be heated for a first preset time to grow a four-inch silicon carbide crystal on the silicon surface of the seed crystal. Furthermore, some silicon carbide gas can condense between the seed crystal and the graphite support through a vent hole to achieve a connection between the seed crystal and the graphite support. The seed crystal and the graphite support are fixed in place, thus achieving self-adhesion between them. This effectively avoids the defects caused by adhesive bonding and mechanical fixing methods. Then, the first crucible is controlled to rotate from the first position to the second position, and the second crucible is heated for a second preset time to grow a six-inch silicon carbide crystal on the carbon surface of the seed crystal. At the same time, by setting a protective component inside the first crucible, the protective component can prevent the first silicon carbide crystal from contaminating the four-inch silicon carbide crystal during the rotation of the first crucible from the first position to the second position. Thus, continuous growth of the four-inch silicon carbide crystal and the six-inch silicon carbide crystal can be achieved, which is beneficial to improving the crystal growth efficiency without affecting the quality of crystal growth.

[0008] In some embodiments of the present invention, the protective component includes: a protective plate connected to the inner peripheral wall of the first chamber, the protective plate having multiple through-hole groups evenly arranged thereon, each through-hole group including a first through-hole and multiple second through-holes surrounding the first through-hole; and a stop member including a first stop portion, a connecting rod, and a second stop portion, the first stop portion and the second stop portion being respectively disposed at both ends of the connecting rod, the connecting rod passing through the first through-hole and movable up and down relative to the protective plate, the cross-sectional area of ​​the first stop portion and the second stop portion being larger than the cross-sectional area of ​​the first through-hole, the first stop portion having a third through-hole, the third through-hole being disposed opposite to at least one second through-hole in the vertical direction, in the first position, the first stop portion engaging with the protective plate stop portion, the second stop portion being located directly below the first stop portion; in the second position, the second stop portion engaging with the protective plate stop portion, the first stop portion being located directly below the second stop portion.

[0009] In some embodiments of the present invention, the protective component includes a baffle plate having a plurality of airflow channels, each of the airflow channels penetrating the baffle plate in the thickness direction, the airflow channel including a straight section and a bent section.

[0010] In some embodiments of the present invention, the graphite support includes: an outer graphite support, which is formed in an annular shape and is connected to the first crucible; and an inner graphite support, which is connected to the outer graphite support. The circular through hole and a plurality of ventilation holes are provided on the inner graphite support. At the first position, the seed crystal is provided on the top wall of the inner graphite support.

[0011] In some embodiments of the present invention, the inner graphite support includes: a plurality of graphite rings, wherein the plurality of graphite rings are sequentially nested and spaced apart, the central axes of the plurality of graphite rings are on the same straight line, and adjacent two graphite rings are spaced apart to define the annular vent hole; and a graphite rod, wherein the graphite rod is connected between the plurality of graphite rings to fix the graphite rings, and there are multiple graphite rods, wherein the plurality of graphite rods are spaced apart in the circumferential direction of the inner graphite support.

[0012] In some embodiments of the present invention, the gap between two adjacent graphite rings is 0.5 mm to 1.5 mm.

[0013] In some embodiments of the present invention, the silicon carbide crystal growth apparatus further includes: a porous plate disposed in the third chamber, the porous plate being configured to allow only gas passage, the porous plate being positioned above the second silicon carbide powder.

[0014] In some embodiments of the present invention, the silicon carbide crystal growth apparatus further includes a first induction coil, a second induction coil, and a third induction coil arranged sequentially in the vertical direction. The first induction coil, the second induction coil, and the third induction coil all surround the quartz cover. The second induction coil is movable in the vertical direction between a third position and a fourth position. In the third position, the distance between the second induction coil and the bottom of the second sub-chamber is L1, where L1 satisfies: 20mm≤L1≤50mm. In the fourth position, the distance between the second induction coil and the third induction coil is L2, where L2 satisfies: 2mm≤L2≤10mm.

[0015] A control method for a silicon carbide crystal growth apparatus according to an embodiment of the present invention includes: in a first crystal growth stage, controlling the first crucible to remain in the first position, and heating the first crucible for a first preset time to grow a four-inch silicon carbide crystal on the silicon surface of the seed crystal; in a transition stage, controlling the first crucible to rotate from the first position to the second position; and in a second crystal growth stage, controlling the first crucible to remain in the second position, and heating the second crucible for a second preset time to grow a six-inch silicon carbide crystal on the carbon surface of the seed crystal, wherein the first preset time is less than the second preset time.

[0016] According to the control method of the silicon carbide crystal growth apparatus of the present invention, before crystal growth, the first crucible can be controlled to rotate to the first position by the drive module, and then the seed crystal is placed on the graphite support of the first crucible. During the crystal growth process, the first crucible can be controlled to remain in the first position and heated for a first preset time to grow a four-inch silicon carbide crystal on the silicon surface of the seed crystal. Some silicon carbide gas can be condensed between the seed crystal and the graphite support through the vent hole to fix the seed crystal and the graphite support, thereby achieving self-adhesion between the seed crystal and the graphite support. This can effectively avoid the defects caused by adhesive bonding and mechanical fixing methods. Then, the first crucible is controlled to rotate from the first position to the second position and the second crucible is heated for a second preset time to grow a six-inch silicon carbide crystal on the carbon surface of the seed crystal. Thus, the continuous growth of four-inch silicon carbide crystals and six-inch silicon carbide crystals can be achieved, which is beneficial to improving the crystal growth efficiency.

[0017] In some embodiments of the present invention, the silicon carbide crystal growth apparatus is the silicon carbide crystal growth apparatus described above. In the first crystal growth stage, the second induction coil is controlled to be in the third position, the first induction coil and the second induction coil are working, and the third induction coil is not working. In the transition stage, the second induction coil is controlled to move from the third position to the fourth position. In the second crystal growth stage, the second induction coil is controlled to be in the fourth position, the first induction coil is not working, and both the second induction coil and the third induction coil are working.

[0018] In some embodiments of the present invention, the control method further includes: an annealing stage, the annealing stage being located after the second crystal growth stage, wherein in the annealing stage, the first crucible is controlled to remain in the second position, the second induction coil is controlled to be located in the third position, the first induction coil and the second induction coil are working, and the third induction coil is not working.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a silicon carbide crystal growth apparatus according to Embodiment 1 of the present invention, wherein the first crucible is in the first position and the second induction coil is in the third position;

[0021] Figure 2 This is a schematic diagram of a silicon carbide crystal growth apparatus according to Embodiment 1 of the present invention, wherein the first crucible is in the second position and the second induction coil is in the fourth position;

[0022] Figure 3 This is a schematic diagram of a silicon carbide crystal growth apparatus according to Embodiment 2 of the present invention, wherein the first crucible is in the first position and the second induction coil is in the third position;

[0023] Figure 4 This is a schematic diagram of a silicon carbide crystal growth apparatus according to Embodiment 2 of the present invention, wherein the first crucible is in the second position and the second induction coil is in the fourth position;

[0024] Figure 5 This is a schematic diagram of a silicon carbide crystal growth apparatus according to Embodiment 2 of the present invention, wherein the first crucible is in the second position and the second induction coil is in the third position;

[0025] Figure 6 This is a schematic diagram of a protective component according to Embodiment 2 of the present invention, wherein the first stop portion cooperates with the stop portion of the protective plate;

[0026] Figure 7 This is a schematic diagram of a protective component according to Embodiment 2 of the present invention, wherein the second stop portion cooperates with the stop of the protective plate;

[0027] Figure 8 This is a schematic plan view of the protective plate according to Embodiment 2 of the present invention;

[0028] Figure 9 This is a schematic diagram of the material stopper according to Embodiment 2 of the present invention;

[0029] Figure 10 This is a schematic diagram of the material stop component according to Embodiment 3 of the present invention;

[0030] Figure 11 This is a schematic diagram of the protective component according to Embodiment 4 of the present invention;

[0031] Figure 12 This is a schematic diagram of the graphite support structure according to Embodiment 2 of the present invention;

[0032] Figure 13 This is a schematic diagram of the inner graphite support structure according to Embodiment 2 of the present invention;

[0033] Figure 14 This is a schematic diagram of the structure of the external graphite support according to Embodiment 2 of the present invention;

[0034] Figure 15 This is a schematic diagram of a control method for a silicon carbide crystal growth apparatus according to an embodiment of the invention.

[0035] Figure label:

[0036] Silicon carbide crystal growth apparatus 100;

[0037] Quartz dome 10; Accommodation space 11;

[0038] First crucible 20; first chamber 21; first sub-chamber 211; second sub-chamber 212; first silicon carbide powder 213; second chamber 22;

[0039] Graphite support 30; outer graphite support 31; connecting hole 311; inner graphite support 32; graphite ring 321; graphite rod 322; circular through hole 33; vent hole 34;

[0040] Seed crystal 40; Silicon facet 41; Carbon facet 42;

[0041] Second crucible 50; Third chamber 51; Second silicon carbide powder 52; Perforated plate 53;

[0042] Protective component 60; protective plate 61; through hole group 611; first through hole 612; second through hole 613; stopper 62; first stop part 621; third through hole 6211; connecting rod 622; threaded section 6221; second stop part 623; annular plate 624; connecting plate 625;

[0043] baffle plate 63; airflow channel 631; straight section 632; bent section 633;

[0044] Driver module 70;

[0045] First induction coil 81; Second induction coil 82; Third induction coil 83;

[0046] Four-inch silicon carbide crystal 91; six-inch silicon carbide crystal 92. Detailed Implementation

[0047] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0048] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. Additionally, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0049] The following is for reference. Figures 1-15 A silicon carbide crystal growth apparatus 100 and a control method thereof are described according to an embodiment of the present invention.

[0050] Reference Figure 1 and Figure 2 As shown, the silicon carbide crystal growth apparatus 100 according to an embodiment of the present invention may include: a quartz cover 10, a first crucible 20, a second crucible 50, a protective component 60, and a drive module 70.

[0051] Reference Figure 1As shown, the quartz dome 10 defines a receiving space 11. Both the first crucible 20 and the second crucible 50 are located within the receiving space 11. The first crucible 20 is positioned above the second crucible 50. The first crucible 20 has a growth chamber open at one end. A graphite support 30 for placing the seed crystal 40 is provided within the growth chamber. The graphite support 30 is annular and defines a circular through-hole 33 in its center (in conjunction with...). Figure 1 and Figure 12 The graphite support 30 and the seed crystal 40 have multiple ventilation holes 34 at corresponding locations in the vertical direction. It should be noted that, generally speaking, referring to... Figure 5 and Figure 12 The two ends of the seed crystal 40 in the thickness direction are silicon surface 41 and carbon surface 42, respectively. Silicon surface 41 is suitable for growing four-inch silicon carbide crystal 91, and carbon surface 42 is suitable for growing six-inch silicon carbide crystal 92.

[0052] For example, refer to Figure 1 As shown, the graphite holder 30 is generally formed into a ring shape, and multiple ventilation holes 34 are evenly spaced on the graphite holder 30. The first crucible 20 is in the first position described below, with the seed crystal 40 placed on the top wall of the graphite holder 30, the silicon surface 41 of the seed crystal 40 facing down, and the carbon surface 42 of the seed crystal 40 facing up. Under the action of the temperature gradient, silicon carbide gas can pass through the ventilation holes 34 from bottom to top and condense between the graphite holder 30 and the silicon surface 41 of the seed crystal 40 to fix the seed crystal 40.

[0053] Reference Figure 1 As shown, the seed crystal 40 and the graphite holder 30 divide the growth chamber into a first chamber 21 and a second chamber 22. A protective assembly 60 is provided within the first chamber 21, dividing it into a first sub-chamber 211 and a second sub-chamber 212. The protective assembly 60 is configured to allow only gas passage. For example, the protective assembly 60 has multiple gas flow channels, each penetrating the protective assembly 60 in the thickness direction. The diameter of each gas flow channel can be 30μm-100μm, and the particle size of the first silicon carbide powder 213 can be 300um-1000um. Thus, by making the diameter of the gas flow channel 631 smaller than the diameter of the first silicon carbide powder 213, the protective assembly 60 can be configured to allow only gas passage. It is understood that when the first crucible 20 is moved from the first position (refer to...) Figure 1 Rotate 180° to the second position (refer to...) Figure 2 During the process, the first silicon carbide powder 213 can be prevented from flowing to the four-inch silicon carbide crystal 91 through the protective component 60. In other words, during the process of the first crucible 20 rotating from the first position to the second position, the protective component 60 can prevent the first silicon carbide powder 213 from contaminating the four-inch silicon carbide crystal 91.

[0054] Reference Figure 1As shown, the second sub-chamber 212 is located on the side of the first sub-chamber 211 opposite to the seed crystal 40. For example, the second sub-chamber 212 is located below the first sub-chamber 211 (e.g., Figure 1 As shown), the second sub-chamber 212 contains the first silicon carbide powder 213, and the second crucible 50 has a third chamber 51 with an open top, which contains the second silicon carbide powder 52. The composition and particle size of the first silicon carbide powder 213 and the second silicon carbide powder 52 can be the same.

[0055] Reference Figure 1 As shown, the drive module 70 is connected to the first crucible 20. The drive module 70 is located outside the quartz cover 10. The output shaft of the drive module 70 passes through the quartz cover 10 and is connected to the first crucible 20. The drive module 70 is used to drive the first crucible 20 to rotate around a preset straight line K at a first position (refer to...). Figure 1 ) and second position (refer to) Figure 2 Rotate between ) such as Figure 1 As shown, in the first position, the second chamber 22 is located directly above the first chamber 21, the silicon surface 41 of the seed crystal 40 is opposite to and downwards from the circular through-hole 33, and the carbon surface 42 of the seed crystal 40 is upwards; as Figure 2 As shown, in the second position, the second chamber 22 is located directly below the first chamber 21, and the second chamber 22 is connected to the third chamber 51. The carbon surface 42 of the seed crystal 40 faces downward, and the silicon surface 41 of the seed crystal 40 faces upward. A pre-defined straight line K extends horizontally and passes through the center of the first crucible 20.

[0056] Understandably, before crystal growth, the first crucible 20 can be rotated to the first position via the drive module 70 (see reference). Figure 1 Next, the seed crystal 40 is placed on the graphite support 30 of the first crucible 20. During the crystal growth process, the first crucible 20 can be kept in the first position and heated for a first preset time to grow a four-inch silicon carbide crystal 91 on the silicon surface 41 of the seed crystal 40. Some silicon carbide gas can condense between the silicon surface 41 of the seed crystal 40 and the graphite support 30 through the vent 34 to fix the seed crystal 40 and the graphite support 30, thereby achieving self-adhesion between the seed crystal 40 and the graphite support 30. This can effectively avoid the defects caused by adhesive bonding and mechanical fixing methods. Then, the first crucible 20 is controlled to rotate from the first position to the second position (refer to...). Figure 2 The second crucible 50 is heated for a second preset time to grow a six-inch silicon carbide crystal 92 on the carbon surface 42 of the seed crystal 40 (see reference). Figure 2 This allows for the continuous growth of four-inch silicon carbide crystals 91 and six-inch silicon carbide crystals 92, which is beneficial for improving crystal growth efficiency.

[0057] In view of this, the silicon carbide crystal growth apparatus 100 according to an embodiment of the present invention, by providing a first crucible 20 and a second crucible 50 inside the quartz cover 10, and the driving module 70 being adapted to drive the first crucible 20 to rotate around a preset straight line K between a first position and a second position, before crystal growth, the driving module 70 can control the first crucible 20 to rotate to the first position, and then place the seed crystal 40 on the graphite support 30 of the first crucible 20. During the crystal growth process, the first crucible 20 can be controlled to remain in the first position, and the first crucible 20 can be heated for a first preset time to grow a four-inch silicon carbide crystal 91 on the silicon surface 41 of the seed crystal 40. Furthermore, some silicon carbide gas can condense between the seed crystal 40 and the graphite support 30 through the vent 34 to achieve the desired growth of the seed crystal 40. The fixation between the seed crystal 40 and the graphite holder 30 achieves self-adhesion between them, effectively avoiding the defects caused by adhesive bonding and mechanical fixing methods. Then, the first crucible 20 is controlled to rotate from the first position to the second position, and the second crucible 50 is heated for a second preset time to grow a six-inch silicon carbide crystal 92 on the carbon surface 42 of the seed crystal 40. At the same time, by setting a protective component 60 inside the first crucible 20, the protective component 60 can prevent the first silicon carbide powder 213 from contaminating the four-inch silicon carbide crystal 91 during the rotation of the first crucible 20 from the first position to the second position. Thus, the continuous growth of the four-inch silicon carbide crystal 91 and the six-inch silicon carbide crystal 92 can be achieved, which is beneficial to improving the crystal growth efficiency without affecting the quality of crystal growth.

[0058] In some embodiments of the present invention, reference is made to... Figure 3 , Figure 6 and Figure 7 As shown, the protective assembly 60 includes a protective plate 61 and a baffle 62. The protective plate 61 is connected to the inner peripheral wall of the first chamber 21. The protective plate 61 is provided with a plurality of through-hole groups 611, which are evenly arranged on the protective plate 61. Each through-hole group 611 includes a first through-hole 612 and a plurality of second through-holes 613. The plurality of second through-holes 613 are arranged around the first through-hole 612, for example, as shown in the figure. Figure 8 As shown, both the protective plate 61 and the baffle 62 are graphite parts. The protective plate 61 is a circular plate, and multiple through hole groups 611 are evenly arranged in a ring array on the protective plate 61. Each through hole group 611 includes a first through hole 612 and twelve second through holes 613. The diameter of the first through hole 612 is larger than the diameter of the second through hole 613, and the twelve second through holes 613 form two circles, with four second through holes 613 located in the inner circle and eight second through holes 613 located in the outer circle.

[0059] Reference Figure 9As shown, the stop member 62 includes a first stop part 621, a connecting rod 622, and a second stop part 623. The first stop part 621 and the second stop part 623 are respectively disposed at both ends of the connecting rod 622. The connecting rod 622 passes through the first through hole 612 and can move up and down relative to the protective plate 61 (in combination with...). Figure 6 and Figure 7 The cross-sectional area of ​​the first stop portion 621 and the second stop portion 623 is larger than the cross-sectional area of ​​the first through hole 612. The first stop portion 621 is provided with a third through hole 6211, which is arranged opposite to at least one second through hole 613 in the vertical direction. Figure 3 and Figure 6 As shown, in the first position, the first stop 621 engages with the protective plate 61, and the second stop 623 is located directly below the first stop 621; combined with Figure 4 and Figure 7 As shown, in the second position, the second stop 623 cooperates with the protective plate 61 to stop, and the first stop 621 is located directly below the second stop 623.

[0060] Understandably, by making the protective component 60 include a protective plate 61 and a baffle 62, in the first position, under the action of gravity, the first stop 621 engages with the protective plate 61, and the second stop 623 is located directly below the first stop 621. At this time, at least part of the second through hole 613 and the third through hole 6211 are arranged opposite each other. During the growth of the four-inch silicon carbide crystal 91, silicon carbide gas can flow from bottom to top through the second through hole 613 and the third through hole 6211 to the seed crystal 40 under the action of temperature gradient, which is beneficial to ensure the normal growth of the four-inch silicon carbide crystal 91. At the same time, during the process of the first crucible 20 rotating from the first position to the second position, under the action of gravity, the second stop 623 gradually engages with the protective plate 61, which can block the first through hole 612 and the second through hole 613, thereby preventing the first silicon carbide powder 213 from contaminating the four-inch silicon carbide crystal 91, which is beneficial to ensure the final growth quality of the four-inch silicon carbide crystal 91.

[0061] Reference Figure 6 As shown, the first stop portion 621 is provided with a plurality of third through holes 6211, which are evenly spaced on the first stop portion 621. The cross-sectional area of ​​each third through hole 6211 is smaller than the cross-sectional area of ​​each second through hole 613. Thus, during the growth of the four-inch silicon carbide crystal 91, when silicon carbide gas flows from bottom to top through the second through holes 613 and the third through holes 6211 to the seed crystal 40, the cooperation of the second through holes 613 and the third through holes 6211 can also filter out large particle impurities, which is beneficial to further ensuring the growth quality of the four-inch silicon carbide crystal 91. Of course, the present invention is described herein with reference to... Figure 10As shown, the first stop portion 621 may also be composed of an annular plate 624 and multiple connecting plates 625, with multiple third through holes 6211 defined between the annular plate 624 and the multiple connecting plates 625, for example, as Figure 10 Four third through holes 6211 are defined between the annular plate 624 and the four connecting plates 625.

[0062] Optionally, refer to Figure 9 As shown, the upper and lower ends of the connecting rod 622 are respectively provided with threaded sections 6221. The threaded sections 6221 of the connecting rod 622 are threadedly connected to the first stop part 621 and the second stop part 623 respectively, thereby facilitating the installation and removal of the material stop 62 on the protective plate 61.

[0063] In other embodiments of the present invention, reference is made to Figure 11 As shown, the protective component 60 includes a baffle plate 63 having a plurality of airflow channels 631, each airflow channel 631 penetrating the baffle plate 63 in the thickness direction. The airflow channel 631 includes a straight section 632 and a bent section 633. For example, in a first position, combined with... Figure 1 and Figure 11 As shown, one end of the straight segment 632 is connected to the first sub-chamber 211, and the other end of the straight segment 632 extends towards the second sub-chamber 212. One end of the bent segment 633 is connected to the other end of the straight segment 632, and the other end of the bent segment 633 is connected to the second sub-chamber 212. It can be understood that by including the bent segment 633 in the gas channel, during the rotation of the first crucible 20 from the first position to the second position, the tiny first silicon carbide powder 213 flowing into the gas flow channel 631 will accumulate in the bent segment 633, thereby further preventing the first silicon carbide powder 213 from contaminating the four-inch silicon carbide crystal 91.

[0064] In some embodiments of the present invention, reference is made to... Figure 1 , Figures 12-13 As shown, the graphite support 30 includes an outer graphite support 31 and an inner graphite support 32. The outer graphite support 31 is formed in a ring shape and is connected to the first crucible 20. The inner graphite support 32 is connected to the outer graphite support 31. A circular through hole 33 and multiple vent holes 34 are provided in the inner graphite support 32. At a first position, a seed crystal 40 is provided on the top wall of the inner graphite support 32. It can be understood that by making the graphite support 30 include a split inner graphite support 32 and an outer graphite support 31, the structures of the inner graphite support 32 and the outer graphite support 31 are simple, which helps to reduce the processing difficulty of the graphite support 30 and improve the production efficiency of the graphite support 30. For example, refer to Figure 14As shown, the outer graphite support 31 has two connecting holes 311, and two graphite bolts pass through the two connecting holes 311 one by one to connect with the inner graphite support 32. Thus, the structure is simple and a reliable connection between the outer graphite support 31 and the inner graphite support 32 can be achieved.

[0065] In some embodiments of the present invention, reference is made to... Figure 12 and Figure 13 As shown, the inner graphite support 32 includes: multiple graphite rings 321 and graphite rods 322. The multiple graphite rings 321 are sequentially nested and spaced apart, with their central axes on the same straight line. Adjacent graphite rings 321 are spaced apart to define an annular vent hole 34. Graphite rods 322 are connected between the multiple graphite rings 321 to fix them. There are multiple graphite rods 322, which are spaced apart circumferentially around the inner graphite support 32. Therefore, the structure is simple and facilitates the processing and molding of the inner graphite support 32. For example, as... Figure 13 As shown, there are four graphite rods 322, which are evenly spaced apart in the circumferential direction of the inner graphite support 32.

[0066] In some alternative embodiments of the invention, reference is made to Figure 13 As shown, the gap between two adjacent graphite rings 321 is 0.5mm-1.5mm. In other words, the gap W between two adjacent graphite rings 321 can take any value between 0.5mm and 1.5mm. For example, the gap W between two adjacent graphite rings 321 can be 0.5mm, 0.7mm, 0.9mm, 1.1mm, 1.2mm, or 1.5mm, etc. It can be understood that by making the gap between two adjacent graphite rings 321 0.5mm-1.5mm, on the one hand, the gap between two adjacent graphite rings 321 is not too small, thereby ensuring the amount of silicon carbide condensed between the inner graphite support 32 and the silicon surface 41 of the seed crystal 40, which is beneficial to ensuring a reliable connection between the graphite support 30 and the seed crystal 40. On the other hand, the gap between two adjacent graphite rings 321 is not too large, which is beneficial to ensuring the structural strength of the inner graphite support 32, thereby ensuring the reliability of the operation of the inner graphite support 32.

[0067] In some embodiments of the present invention, reference is made to... Figure 1-2As shown, the silicon carbide crystal growth apparatus 100 further includes a porous plate 53 disposed within the third chamber 51. The porous plate 53 is configured to allow only gas passage and is positioned above the second silicon carbide powder 52. For example, the diameter of the through-holes in the porous plate 53 is 30 μm-100 μm, and the diameter of the second silicon carbide powder 52 is 300 μm-1000 μm. It is understood that during the growth of the six-inch silicon carbide crystal 92, the porous plate 53 can filter the silicon carbide gas flowing from bottom to top, which is beneficial to improving the growth quality of the six-inch silicon carbide crystal 92.

[0068] In some embodiments of the present invention, reference is made to... Figures 1-2 As shown, the silicon carbide crystal growth apparatus 100 also includes a first induction coil 81, a second induction coil 82, and a third induction coil 83 arranged sequentially in the vertical direction, for example, as... Figure 1 and Figure 2 As shown, the first induction coil 81 may include two sets of induction coils, the second induction coil 82 may include three sets of induction coils, and the third induction coil 83 may include four sets of induction coils.

[0069] Reference Figures 1-2 As shown, the first induction coil 81, the second induction coil 82, and the third induction coil 83 all surround the quartz cover 10. The second induction coil 82 is movable in the vertical direction between the third position and the fourth position. In the third position, the distance between the second induction coil 82 and the bottom of the second sub-chamber 212 is L1, and L1 satisfies: 20mm≤L1≤50mm. In other words, L1 can take any value between 20mm and 50mm. It can be understood that during the growth of the four-inch silicon carbide crystal 91, the first induction coil 81 and the second induction coil 82 work, while the third induction coil 83 does not work. By controlling L1 within a suitable range, the contents of the first chamber 21 can be controlled within a preset range, which is beneficial to ensuring the growth quality of the four-inch silicon carbide crystal 91.

[0070] Reference Figure 2 As shown, in the fourth position, the distance between the second induction coil 82 and the third induction coil 83 is L2, which satisfies: 2mm≤L2≤10mm. In other words, L2 can take any value between 2mm and 10mm. It can be understood that during the growth of the six-inch silicon carbide crystal 92, the second induction coil 82 and the third induction coil 83 serve as the main heat sources, while the first induction coil 81 plays an auxiliary role in the temperature gradient. By controlling L2 within the preset range, it is beneficial to ensure that sufficient heat is provided to the third chamber 51, which is beneficial to ensure the growth quality of the six-inch silicon carbide crystal 92.

[0071] Reference Figure 15As shown, the control method of the silicon carbide crystal growth apparatus 100 according to an embodiment of the present invention includes: in the first crystal growth stage, controlling the first crucible 20 to be held in a first position (refer to...). Figure 1 The first crucible 20 is heated for a first preset time to grow a four-inch silicon carbide crystal 91 on the silicon surface 41 of the seed crystal 40; during the transition phase, the first crucible 20 is controlled to rotate from a first position to a second position (refer to...). Figure 2 In the second crystal growth stage, the first crucible 20 is kept in the second position, and the second crucible 50 is heated for a second preset time to grow a six-inch silicon carbide crystal 92 on the carbon surface 42 of the seed crystal 40. The first preset time is shorter than the second preset time. For example, the first preset time is 75h-80h, and the second preset time is 140h-160h.

[0072] According to the control method of the silicon carbide crystal growth apparatus 100 of the present invention, before crystal growth, the first crucible 20 can be rotated to a first position by the drive module 70, and then the seed crystal 40 is placed on the graphite support 30 of the first crucible 20. During the crystal growth process, the first crucible 20 can be kept in the first position and heated for a first preset time to grow a four-inch silicon carbide crystal 91 on the silicon surface 41 of the seed crystal 40. Part of the silicon carbide gas can condense on the seed crystal 40 and the graphite support 30 through the vent 34. The graphite support 30 is used to fix the seed crystal 40 and the graphite support 30, thereby achieving self-adhesion between the seed crystal 40 and the graphite support 30. This can effectively avoid the defects caused by adhesive bonding and mechanical fixing methods. Then, the first crucible 20 is controlled to rotate from the first position to the second position, and the second crucible 50 is heated for a second preset time to grow a six-inch silicon carbide crystal 92 on the carbon surface 42 of the seed crystal 40. Thus, the continuous growth of the four-inch silicon carbide crystal 91 and the six-inch silicon carbide crystal 92 can be achieved, which is beneficial to improving the crystal growth efficiency.

[0073] In some embodiments of the present invention, the silicon carbide crystal growth apparatus 100 is the silicon carbide crystal growth apparatus 100 according to the above embodiments of the present invention, with reference to... Figure 3 As shown, in the first crystal growth stage, the second induction coil 82 is controlled to be in the third position, the first induction coil 81 and the second induction coil 82 are working, and the third induction coil 83 is not working. This is beneficial to achieve effective control of the temperature in the first chamber 21, and to ensure the quality of the four-inch silicon carbide crystal 91 grown on the silicon surface 41 of the seed crystal 40.

[0074] During the transition phase, the control of the second induction coil 82 is from the third position (refer to...). Figure 3 Move to the fourth position (refer to) Figure 4For example, the first crucible 20 can be controlled to rotate from the first position to the second position, and then the second induction coil 82 can be controlled to move from the third position to the fourth position. The transition phase can last for 5-10 minutes.

[0075] Reference Figure 4 As shown, in the second crystal growth stage, the first crucible 20 is controlled to be in the second position, and the second induction coil 82 is controlled to be in the fourth position. The first induction coil 81 is not working, while the second induction coil 82 and the third induction coil 83 are both working. It can be understood that in the second crystal growth stage, the second induction coil 82 and the third induction coil 83 provide a heat source for heating the second silicon carbide powder 52. This facilitates effective temperature control within the second chamber 22 and the chamber formed by splicing the second chamber 22, which helps to ensure the quality of the six-inch silicon carbide crystal 92 grown on the carbon surface 42 of the seed crystal 40.

[0076] In some embodiments of the present invention, reference is made to... Figure 5 As shown, the control method also includes: during the annealing stage, the first crucible 20 is controlled to remain in the second position, and the annealing stage is controlled to occur after the second crystal growth stage. During the annealing stage, the second induction coil 82 is located in the third position, the first induction coil 81 and the second induction coil 82 are activated, and the third induction coil 83 is deactivated. It is understood that annealing the four-inch silicon carbide crystal 91 and the six-inch silicon carbide crystal 92 helps to eliminate stress within both crystals, thus preventing crystal cracking. Furthermore, simultaneously annealing both crystals allows for efficient energy utilization and reduces costs.

[0077] For example, refer to Figures 3-5 As shown, in a specific example of the present invention, the first silicon carbide powder 213 has a particle size of 8-40 mesh and a total weight of 3.5 kg-4.5 kg, the second silicon carbide powder 52 has a particle size of 8-40 mesh and a total weight of 6.5 kg-7 kg, the polarity of the seed crystal 40 is selected to be 4° off, the growth crystal form of the silicon surface 41 of the seed crystal 40 is 6H-SiC single crystal, the growth crystal form of the carbon surface 42 of the seed crystal 40 is 4H-SiC single crystal, and the control method of the silicon carbide crystal growth apparatus 100 specifically includes the following steps:

[0078] In the first crystal growth stage, the first crucible 20 is held in a first position, and the first crucible 20 is heated for a first preset time to grow a four-inch silicon carbide crystal 91 (6H-SiC) on the silicon surface 41 of the seed crystal 40. Specifically, as follows: Figure 1As shown, the outer edge of the seed crystal 40 is supported by the inner graphite support 32. The inner graphite support 32 defines a crystal growth surface with a size of 102mm-105mm on the silicon surface 41 at the lower end of the seed crystal 40. Specifically, the second induction coil 82 is controlled to be in the third position, the first induction coil 81 and the second induction coil 82 are working, and the third induction coil 83 is not working. During this process, the total power of the first induction coil 81 and the second induction coil 82 can be 9.5kw-1. 1.5 kW corresponds to a temperature of 2250-2300℃, a crystal growth time of 75-80 hours, and power control is implemented in three stages: initially, the power is increased to 9.5 kW-11.5 kW at 1 hour-20% (9.5 kW-11.5 kW), then at 2 hours-50% (9.5 kW-11.5 kW), and finally at 1 hour-100% (9.5 kW-11.5 kW), with the crystal growth pressure controlled at 1.5 mbar-1.7 mbar. During this process, refer to... Figure 3 As shown, under the action of gravity, the first stop 621 of the baffle 62 cooperates with the stop of the protective plate 61, and the second stop 623 is located directly below the first stop 621. At this time, the relative arrangement of the second through hole 613 and the third through hole 6211 allows silicon carbide gas to flow from bottom to top through the second through hole 613 and the third through hole 6211 to the seed crystal 40, which is beneficial to ensure the normal growth of the four-inch silicon carbide crystal 91. At the same time, some silicon carbide gas can condense between the seed crystal 40 and the graphite support 30 through the vent hole 34 to achieve fixation between the seed crystal 40 and the graphite support 30, thereby achieving self-adhesion between the seed crystal 40 and the graphite support 30, which can effectively avoid the defects caused by adhesive bonding and mechanical fixing methods.

[0079] Reference Figure 4 As shown, during the transition phase, the first crucible 20 is first controlled to rotate from the first position to the second position, and then the second induction coil 82 is controlled to move from the third position to the fourth position. The total time is 5-10 minutes. During the process of the first crucible 20 rotating from the first position to the second position, under the action of gravity, the second stop 623 gradually cooperates with the stop of the protective plate 61, thereby preventing the first silicon carbide powder 213 from contaminating the four-inch silicon carbide crystal 91, which is beneficial to ensuring the final growth quality of the four-inch silicon carbide crystal 91.

[0080] Reference Figure 4As shown, in the second crystal growth stage, the first crucible 20 is controlled to be in the second position, the second induction coil 82 is controlled to be in the fourth position, the first induction coil 81 is not working, and the second induction coil 82 and the third induction coil 83 are both working. At this time, the second induction coil 82 and the third induction coil 83 provide the heat source for heating the second silicon carbide powder 52. Specifically, the size of the crystal growth surface of the carbon surface 42 of the seed crystal 40 can be 155mm-165mm, the total power of the second induction coil 82 and the third induction coil 83 can be 11kw-12kw, the corresponding temperature is 2100-2150℃, and the crystal growth time is 150h, thereby growing a six-inch silicon carbide crystal 92 (4H-SiC) on the carbon surface 42 of the seed crystal 40.

[0081] Reference Figure 5 As shown, during the annealing stage, the first crucible 20 is controlled to be in the second position, the second induction coil 82 is moved to the third position, the first induction coil 81 and the second induction coil 82 are working, and the third induction coil 83 is not working. The total power of the first induction coil 81 and the second induction coil 82 rises to 11kW-12kW and is maintained for 5 hours. Then, it is maintained for 7 hours-50% (11kW-12kW) and 15 hours-10% (11kW-12kW). Then the power is reduced to 0. This allows for the simultaneous annealing of four-inch silicon carbide crystal 91 (6H-SiC) and six-inch silicon carbide crystal 92 (6H-SiC), thereby achieving efficient energy utilization and reducing costs.

[0082] Other configurations and operations of the silicon carbide crystal growth apparatus 100 according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0083] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0084] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0085] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0086] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0087] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0088] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A silicon carbide crystal growth apparatus, characterized in that, include: A quartz dome that defines an accommodating space; A first crucible and a second crucible are both located within the containing space. The first crucible is located above the second crucible. The first crucible has a growth chamber with one end open. The growth chamber contains a graphite support for placing a seed crystal. The graphite support is annular and defines a circular through hole in the middle. The graphite support and the seed crystal have multiple ventilation holes at corresponding portions in the vertical direction. The seed crystal and the graphite support divide the growth chamber into a first chamber and a second chamber. A protective component is provided in the first chamber. The protective component divides the first chamber into a first sub-chamber and a second sub-chamber. The protective component is configured to allow only gas to pass through. The second sub-chamber is located on the side of the first sub-chamber opposite to the seed crystal. The second sub-chamber contains first silicon carbide powder with a particle size of 300um-1000um. The second crucible has a third chamber with an open top. The third chamber contains second silicon carbide powder. A driving module is connected to the first crucible. The driving module is used to drive the first crucible to rotate around a preset straight line K between a first position and a second position. In the first position, the second chamber is located directly above the first chamber, the silicon surface of the seed crystal is opposite to and downwards from the circular through hole, and the carbon surface of the seed crystal is upwards. In the second position, the second chamber is located directly below the first chamber, the second chamber is connected to the third chamber, the carbon surface of the seed crystal is downwards, and the silicon surface of the seed crystal is upwards.

2. The silicon carbide crystal growth apparatus according to claim 1, characterized in that, The protective components include: A protective plate is connected to the inner peripheral wall of the first chamber. The protective plate is provided with multiple through-hole groups, which are evenly arranged on the protective plate. Each through-hole group includes a first through-hole and multiple second through-holes, with the multiple second through-holes surrounding the first through-hole. A material stop component includes a first stop portion, a connecting rod, and a second stop portion. The first and second stop portions are respectively disposed at both ends of the connecting rod. The connecting rod passes through a first through hole and is movable up and down relative to the protective plate. The cross-sectional areas of the first and second stop portions are larger than the cross-sectional area of ​​the first through hole. The first stop portion has a third through hole, which is arranged opposite to at least one second through hole in the vertical direction. In the first position, the first stop portion engages with the protective plate, and the second stop portion is located directly below the first stop portion. In the second position, the second stop portion engages with the protective plate, and the first stop portion is located directly below the second stop portion.

3. The silicon carbide crystal growth apparatus according to claim 1, characterized in that, The protective component includes a baffle plate having multiple airflow channels, each of which penetrates the baffle plate in the thickness direction and includes a straight section and a bent section.

4. The silicon carbide crystal growth apparatus according to claim 1, characterized in that, The graphite holder includes: An outer graphite support, which is formed in a ring shape, is connected to the first crucible; An inner graphite support is connected to an outer graphite support. The circular through hole and multiple ventilation holes are all located on the inner graphite support. At the first position, the seed crystal is located on the top wall of the inner graphite support.

5. The silicon carbide crystal growth apparatus according to claim 4, characterized in that, The inner graphite support includes: Multiple graphite rings are arranged sequentially and spaced apart, with the central axes of the multiple graphite rings on the same straight line, and adjacent graphite rings are spaced apart to define the vent hole; A graphite rod is connected between multiple graphite rings to fix the graphite rings. There are multiple graphite rods, which are arranged at intervals in the circumferential direction of the inner graphite support.

6. The silicon carbide crystal growth apparatus according to claim 5, characterized in that, The gap between two adjacent graphite rings is 0.5mm-1.5mm.

7. The silicon carbide crystal growth apparatus according to claim 1, characterized in that, Also includes: A porous plate is disposed in the third chamber and is configured to allow only gas to pass through. The porous plate is located above the second silicon carbide powder.

8. The silicon carbide crystal growth apparatus according to any one of claims 1-7, characterized in that, It also includes a first induction coil, a second induction coil, and a third induction coil arranged sequentially in the vertical direction. The first induction coil, the second induction coil, and the third induction coil all surround the quartz cover. The second induction coil is movable in the vertical direction between a third position and a fourth position. In the third position, the distance between the second induction coil and the bottom of the second sub-chamber is L1, where L1 satisfies: 20mm≤L1≤50mm. In the fourth position, the distance between the second induction coil and the third induction coil is L2, where L2 satisfies: 2mm≤L2≤10mm.

9. A control method for a silicon carbide crystal growth apparatus according to claim 1, characterized in that, include: In the first crystal growth stage, the first crucible is controlled to remain in the first position, and the first crucible is heated for a first preset time to grow a four-inch silicon carbide crystal on the silicon surface of the seed crystal. During the transition phase, the first crucible is controlled to rotate from the first position to the second position; In the second crystal growth stage, the first crucible is controlled to remain in the second position, and the second crucible is heated for a second preset time to grow a six-inch silicon carbide crystal on the carbon surface of the seed crystal. The first preset time is less than the second preset time.

10. The control method for the silicon carbide crystal growth apparatus according to claim 9, characterized in that, The silicon carbide crystal growth apparatus is the silicon carbide crystal growth apparatus according to claim 8. During the first crystal growth stage, the second induction coil is controlled to be in the third position, the first induction coil and the second induction coil are working, and the third induction coil is not working. During the transition phase, the second induction coil is controlled to move from the third position to the fourth position; During the second crystal growth stage, the second induction coil is controlled to be in the fourth position, the first induction coil is not working, and both the second and third induction coils are working.

11. The control method for the silicon carbide crystal growth apparatus according to claim 10, characterized in that, Also includes: In the annealing stage, which is located after the second crystal growth stage, the first crucible is controlled to remain in the second position, and the second induction coil is controlled to move to the third position. The first and second induction coils are working, while the third induction coil is not working.

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