Growth apparatus, method, and silicon carbide crystal of high-quality silicon carbide crystal

Abstract

The present invention provides a growth apparatus, a method, and a silicon carbide crystal for high-quality silicon carbide crystals, and relates to the field of silicon carbide crystal growth. In this apparatus, an annular deflector plate is installed to guide the vapor-phase crystal growth components to flow onto the seed crystal, and a pressure equalization structure is installed on the annular deflector plate. By installing the pressure equalization structure on the annular deflector plate, the pressure difference between the upper second chamber and the lower first chamber above the annular deflector plate can be effectively reduced, and the pressures of the two chambers can be made as close as possible. In this way, the flow rate of the vapor-phase crystal growth components in the gap between the top of the annular deflector plate and the edge of the seed crystal can be effectively reduced, thereby making the growth rate of the silicon carbide crystal at the edge of the seed crystal as close as possible to the growth rate of the silicon carbide crystal at the center of the seed crystal, further avoiding defects such as the occurrence of a "concave interface" in the silicon carbide crystal growing on the seed crystal, and improving the growth quality of the silicon carbide crystal. The silicon carbide crystal manufactured by this method has the characteristics of few defects and high quality.

Description

Technical Field

[0001] The present invention relates to the field of silicon carbide crystal growth, and specifically to a growth apparatus, method, and silicon carbide crystal for high-quality silicon carbide crystals.

Background Art

[0002] As a representative of the third-generation semiconductor materials, silicon carbide has excellent properties such as a wide bandgap, high saturated electron mobility, high critical breakdown electric field strength, and high thermal conductivity, and thus is widely applied in fields such as power electronics, high-frequency devices, and optoelectronic devices.

[0003] Existing crucibles used for silicon carbide crystal growth are generally provided with a deflector plate at the upper central position of the crucible so as to improve the growth rate of silicon carbide crystals on the seed crystal while restricting the size and shape of the growing silicon carbide crystals. However, in order to avoid interference between the deflector plate and the seed crystal, usually, a gap is ensured between the top of the deflector plate and the edge of the seed crystal, and this gap causes a certain pressure difference between the upper chamber and the lower chamber above the deflector plate at the initial stage of silicon carbide crystal growth, and by increasing the flow rate and the flow rate of the vapor-phase crystal growth components in the gap portion, the growth rate at the edge of the seed crystal is too fast, thus forming a "concave interface" and affecting the growth quality of the silicon carbide crystal. m C n (i.e., carbon and silicon components) to flow to the seed crystal as much as possible.

Summary of the Invention

[0004] The object of the present invention includes, for example, being able to effectively reduce the flow rate of the vapor-phase crystal growth components in the gap between the top of the deflector plate and the edge of the seed crystal, and by growing the silicon carbide crystal uniformly on each part of the seed crystal, providing a growth apparatus, method, and silicon carbide crystal for high-quality silicon carbide crystals that can improve the growth quality of the silicon carbide crystal.

[0005] Embodiments of the present invention can be realized in this way.

[0006] According to the first aspect, the present invention is a growth apparatus for high-quality silicon carbide crystals,

[0007] a crucible having a seed crystal for growing a silicon carbide crystal installed on a top wall,

[0008] an annular deflector plate installed in the crucible, the bottom of the annular deflector plate being connected to a side wall of the crucible, the top extending to the seed crystal and having a gap with an edge of the seed crystal, the annular deflector plate, the seed crystal, the side wall of the crucible, and the bottom wall of the crucible together enclose a first chamber, the annular deflector plate, the seed crystal, the side wall of the crucible, and the top wall of the crucible together enclose a second chamber, the first chamber and the second chamber communicate with each other through the gap, and a pressure equalizing structure for equalizing pressures in the first chamber and the second chamber is installed on the annular deflector plate.

[0009] In an alternative embodiment, the pressure equalizing structure includes pores formed in the annular deflector plate, and the pores communicate the first chamber and the second chamber.

[0010] In an alternative embodiment, the number of the pores is plural, and the plural pores are installed in one or more circles around an axis of the crucible.

[0011] In an alternative embodiment, the plural pores are installed in a plurality of circles around the axis of the crucible, the plural circular pores are arranged at intervals along a radial direction of the crucible, and any two adjacent circular pores are arranged staggeredly in the radial direction of the crucible.

[0012] In an alternative embodiment, the annular deflector plate includes a first annular part and a second annular part connected at an angle, one end of the first annular part away from the second annular part is connected to an inner wall of the crucible, one end of the second annular part away from the first annular part extends to the seed crystal, and the pores are formed in the first annular part.

[0013] In an alternative embodiment, the first annular part is flat and perpendicular to the axis of the crucible. The outer peripheral wall of the first annular part is connected to the side wall of the crucible. The second annular part is in the shape of a hollow cylinder or a hollow frustum of a cone. The bottom of the second annular part is connected to the inner peripheral wall of the first annular part, and the top extends to the seed crystal.

[0014] In an alternative embodiment, the pores are installed obliquely towards the seed crystal.

[0015] In an alternative embodiment, the pore diameter of the pores gradually decreases along the direction closer to the seed crystal.

[0016] In an alternative embodiment, the pressure equalizing structure includes silicon carbide powder disposed in the second chamber.

[0017] In an alternative embodiment, at least one concentration adjustment through hole is installed on the outer periphery of the second chamber of the crucible.

[0018] In an alternative embodiment, the first annular part includes a plurality of sub-annular parts distributed vertically, and the pores are distributed in each sub-annular part.

[0019] In an alternative embodiment, along the transport direction of the crystal growth component, the plurality of sub-annular parts have pores with gradually decreasing pore diameters.

[0020] According to a second aspect, an embodiment of the present invention further provides a method for growing a high-quality silicon carbide crystal based on the apparatus for growing a high-quality silicon carbide crystal described in any one of the foregoing embodiments. The method includes

[0021] putting silicon carbide powder into the crucible,

[0022] after evacuating the crucible, filling it with an inert gas,

[0023] To raise the temperature inside the crucible to 2000 - 2600 °C, heating the crucible;

[0024] To reduce the pressure inside the crucible to 0.01 - 4E3 Pa, evacuating the crucible again;

[0025] The silicon carbide powder sublimates and starts to grow silicon carbide crystals on the seed crystal;

[0026] To raise the pressure inside the crucible to 5E3 - 1E5 Pa, after growing the silicon carbide crystals for 10 - 300 h, refilling the crucible with an inert gas;

[0027] After the growth of the silicon carbide crystals is completed, stopping the heating of the crucible, and after the temperature inside the crucible drops to room temperature, taking out the silicon carbide crystals from the crucible.

[0028] According to the third aspect, the present invention further provides a silicon carbide crystal manufactured using the method for growing a high-quality silicon carbide crystal described in the foregoing embodiments.

[0029] The beneficial effects of the examples of the present invention include the following. For example,

[0030] The high-quality silicon carbide crystal growth apparatus provided by the present invention includes a crucible and an annular deflector. A seed crystal for growing a silicon carbide crystal is installed on the top wall of the crucible. The annular deflector is installed inside the crucible. The bottom of the annular deflector is connected to the side wall of the crucible, the top extends to the seed crystal, and there is a gap between the top and the edge of the seed crystal. The annular deflector, the seed crystal, the side wall of the crucible, and the bottom wall of the crucible commonly enclose a first chamber. The annular deflector, the seed crystal, the side wall of the crucible, and the top wall of the crucible commonly enclose a second chamber. The first chamber and the second chamber communicate with each other through a gap. An equalizing pressure structure for balancing the pressures of the first chamber and the second chamber is installed on the annular deflector. By installing the equalizing pressure structure on the annular deflector, the pressure difference between the first chamber and the second chamber can be effectively reduced, and the pressures of the two chambers can be made as close as possible. In this way, the flow rate of the gas-phase crystal growth components in the gap between the top of the annular deflector and the edge of the seed crystal can be effectively reduced, thereby making the growth rate of the silicon carbide crystal at the edge of the seed crystal as close as possible to the growth rate of the silicon carbide crystal at the center of the seed crystal, further avoiding the occurrence of defects such as "concave interfaces" in the silicon carbide crystal on the seed crystal, and improving the growth quality of the silicon carbide crystal.

[0031] From another perspective, the present invention controls the concentration distribution of the crystal growth gas-phase components in the radial direction, so as to avoid the defects such as edge polycrystals and phase transitions formed due to the too high concentration and too fast growth rate of the crystal growth gas-phase components at the crystal edge, or the formation of a concave interface of the crystal, which may affect the crystal growth quality.

[0032] Correspondingly, this method for growing high-quality silicon carbide crystals uses the above apparatus, and the produced silicon carbide crystals are characterized by few defects and high quality.

Brief Description of the Drawings

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments are briefly described below. However, since the following drawings only show some embodiments of the present invention, they should not be regarded as limiting the scope. Those skilled in the art should understand that they can obtain other related drawings according to these drawings without creative effort.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

[0034] Symbols in the drawings: 100 - crucible, 102 - first chamber, 104 - second chamber, 106 - gap, 108 - concentration adjustment hole, 110 - seed crystal, 200 - annular deflector, 210 - first annular part, 212 - pores, 214 - sub-annular part, 220 - second annular part, 222 - reverse angle round, 300 - silicon carbide powder, 400 - silicon carbide crystal.

Modes for Carrying Out the Invention

[0035] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings of this specification can be arranged and designed in various different configurations.

[0036] Accordingly, the following detailed description of the embodiments of the present invention provided by the drawings is not intended to limit the scope of the claimed invention, but represents only selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments that can be obtained by those skilled in the art without creative effort are included in the claims of the present invention.

[0037] It should be noted that similar symbols and characters indicate similar items in the following drawings. Therefore, if an item is defined in one drawing, there is no need to further define and explain it in subsequent drawings.

[0038] In the description of the present invention, when terms such as "upper", "lower", "inner", "outer", etc. indicate the orientation or positional relationship shown in the drawings or the orientation or positional relationship in which the product of the invention is conventionally arranged when in use, it is for the purpose of facilitating the description of the present invention and simplifying the description, and is not intended to indicate or imply that the device or element mentioned must have a specific orientation, be configured and operated in a specific orientation, and thus should not be understood as a limitation of the present invention.

[0039] Also, when terms such as "first", "second", etc. appear, they are used only for the purpose of description for differentiation and are not to be understood as indicating or implying relative importance.

[0040] It should be noted that, unless there is a contradiction, the features of the embodiments of the present invention can be combined with each other.

[0041] Conventionally, for a crucible used to grow silicon carbide crystals, in order to improve the growth rate of silicon carbide crystals in a seed crystal, generally, on the side wall of the crucible, a deflector plate is installed to guide the gas-phase crystal growth components directly to the seed crystal on the top wall of the crucible. However, in order to avoid interference between the deflector plate and the seed crystal, the position of the top of the deflector plate is restricted to have a certain gap with the edge of the seed crystal. This gap causes a certain pressure difference between the upper chamber and the lower chamber above the deflector plate during the initial stage of the growth of silicon carbide crystals. Due to this pressure difference, the flow rate of the gas-phase crystal growth components at this gap is increased, that is, the flow rate of the gas-phase crystal growth components at the edge of the seed crystal is much higher than the flow rate at the center of the seed crystal. As a result, inevitably, the growth rate of silicon carbide crystals at the edge of the seed crystal is much higher than the growth rate at the center of the seed crystal, and defects such as "concave interfaces" are likely to occur in the silicon carbide crystals, which seriously affects the growth quality of the silicon carbide crystals.

[0042] In view of the above situation, the present invention installs a pressure equalization structure on the deflector plate in the crucible, which can effectively balance the pressures of the upper and lower two chambers of the deflector plate in the crucible, and effectively reduce the pressure difference between the two chambers. Thereby, the flow rate of the gas-phase crystal growth components at the gap between the top of the deflector plate and the edge of the seed crystal can be effectively reduced, and the growth rate of silicon carbide crystals at the edge of the seed crystal is made as close as possible to the growth rate at the center of the seed crystal. Thereby, silicon carbide crystals in different parts of the seed crystal are grown uniformly, defects such as the occurrence of a "concave interface" in the silicon carbide crystals are avoided, and the growth quality of the silicon carbide crystals is improved. The present invention provides a high-quality silicon carbide crystal growth apparatus and method.

[0043] Hereinafter, through examples, in conjunction with the drawings, the overall structure, operating principle, obtained technical effects of the high-quality silicon carbide crystal growth apparatus provided by the present invention, and the detailed steps of the corresponding method will be described in detail.

[0044] First Embodiment

[0045] Referring to FIGS. 1 and 2, the high-quality silicon carbide crystal growth apparatus provided by the present invention includes a crucible 100, an annular deflector 200, a heat preservation structure (not shown), and a heating structure (not shown). Here, both the heating structure and the heat preservation structure are installed outside the crucible 100. The heating structure is used to heat the crucible 100 so that the silicon carbide powder 300 at the bottom of the crucible sublimes to form a vapor-phase crystal growth component, and specifically, it may be induction heating or resistance heating, etc. The heat preservation structure is used to slow down the heat dissipation of the crucible 100, and specifically, it may be graphite felt, graphite paper, etc.

[0046] On the top wall of the crucible 100 (the crucible 100 generally includes a removably connected crucible body and a crucible lid, the crucible lid forms the top wall of the crucible 100, and the crucible body forms the bottom wall and side walls of the crucible 100), a seed crystal 110 for growing the silicon carbide crystal 400 is installed. The fixing methods of the seed crystal 110 include, but are not limited to, adhesion, clamping, etc. The bottom wall and side walls of the crucible 100 are commonly used for arranging the silicon carbide powder 300.

[0047] The annular deflector 200 is installed in the crucible 100 and is used to guide the vapor-phase crystal growth component formed after the sublimation of the silicon carbide powder 300 to flow to the seed crystal 110, thereby realizing the growth of the silicon carbide crystal 400.

[0048] Specifically, the bottom of the annular deflector 200 is connected to the side wall of the crucible 100, and generally, it is connected to the upper center of the side wall of the crucible 100. The top of the annular deflector 200 extends to the seed crystal 110 and has a gap 106 between it and the edge of the seed crystal 110.

[0049] The annular deflector 200 and the seed crystal 110 divide the internal space of the crucible 100 into two chambers. Here, the annular deflector 200, the seed crystal 110, a part of the side wall of the crucible 100 (the part located below the annular deflector 200), and the bottom wall of the crucible 100 together enclose the first chamber 102. The annular deflector 200, the seed crystal 110, a part of the side wall of the crucible 100 (the part located above the annular deflector 200), and the top wall of the crucible 100 together enclose the second chamber 104. The first chamber 102 includes a large chamber and a small chamber that communicate with each other. The large chamber is substantially cylindrical, the small chamber is substantially frustum-shaped, and the small chamber is located above the large chamber. The second chamber 104 is substantially annular and is installed around the small chamber. The first chamber 102 and the second chamber 104 communicate with each other through a gap 106. The vapor-phase crystal growth components formed after the heating and sublimation of the silicon carbide powder 300 in the crucible 100 can flow upward to the seed crystal 110 in the first chamber 102 and at the same time flow into the second chamber 104 from the annular gap 106.

[0050] The annular deflector 200 can use various structures as required. Referring to FIG. 1 again, in this embodiment, the annular deflector 200 includes a first annular portion 210 and a second annular portion 220 connected at an angle. The axes of the first annular portion 210 and the second annular portion 220 both overlap with the axis of the crucible 100. One end of the first annular portion 210 away from the second annular portion 220 is connected to the inner wall of the crucible 100, and one end of the second annular portion 220 away from the first annular portion 210 extends to the seed crystal 110.

[0051] In this embodiment, the first annular portion 210 is flat and perpendicular to the axis of the crucible 100. The outer peripheral wall of the first annular portion 210 is connected to the side wall of the crucible 100. The second annular portion 220 is hollow frustum-shaped. The bottom of the second annular portion 220 is connected to the inner peripheral wall of the first annular portion 210, and the top extends to the seed crystal 110. According to the installation of the hollow frustum shape, on the one hand, the resistance to the vapor-phase crystal growth components can be reduced, and on the other hand, the vapor-phase crystal growth components can be effectively guided to flow to the seed crystal 110.

[0052] It should be noted that in other embodiments, the first annular portion 210 may be a hollow frustum shape, the second annular portion 220 may be a hollow cylindrical shape, the annular deflector 200 may include at least three annular portions, the at least three annular portions are sequentially connected at an angle, the lowermost annular portion is connected to the side wall of the crucible 100, and the uppermost annular portion extends to a position close to the edge of the seed crystal 110.

[0053] Furthermore, a pressure equalizing structure for balancing the pressures of the first chamber 102 and the second chamber 104 is installed in the annular deflector 200. The pressure equalizing structure can use various structures as required. Referring to FIG. 1 again, in this embodiment, the pressure equalizing structure includes pores 212 formed in the annular deflector 200. The pores 212 communicate the first chamber 102 and the second chamber 104, that is, in addition to the first chamber 102 and the second chamber 104 communicating through the gap 106, they also communicate through the pores 212.

[0054] In this way, the gas-phase crystal growth components in the first chamber 102 can not only be guided by the annular deflector 200 and flow out of the seed crystal 110, but also flow into the second chamber 104 through the pores 212 (specifically, refer to FIG. 1, and the dashed line with arrows in the figure indicates the flow path of the gas-phase crystal growth components). The pressure of the second chamber 104 is simultaneously increased together with the pressure of the first chamber 102, thereby balancing the pressures of the first chamber 102 and the second chamber 104, reducing the pressure difference between the two, thereby reducing the flow rate of the gas-phase crystal growth components at the gap 106, and making the growth rates of the silicon carbide crystals 400 at the edge and the center of the seed crystal 110 as the same as possible, thereby avoiding the defect that a "concave interface" occurs in the growth process of the silicon carbide crystals 400 and guaranteeing the growth quality of the silicon carbide crystals 400.

[0055] The specific position of the pores 212 in the annular deflector 200 can be set as required. In this embodiment, specifically, the pores 212 are formed in the first annular portion 210. In other embodiments, the pores 212 can be formed in the second annular portion 220, or can be formed in both the first annular portion 210 and the second annular portion 220 simultaneously.

[0056] The number of the pores 212 is plural, and the plural pores 212 are arranged in one or more circles around the axis of the crucible 100. In this embodiment, the plural pores 212 are arranged in a plurality of circles around the axis of the crucible 100. The plural circular pores 212 are arranged at intervals along the radial direction of the crucible 100, and any two adjacent circular pores 212 are arranged in a stagger pattern along the radial direction of the crucible 100. By arranging the plural circular pores 212 around the axis of the crucible 100, the communication area between the first chamber 102 and the second chamber 104 can be effectively increased, thereby more effectively reducing the pressure difference between the first chamber 102 and the second chamber 104. On the other hand, by arranging two adjacent circular pores 212 in a stagger pattern, the uniformity of the plural communication positions of the first chamber 102 and the second chamber 104 can be improved, thereby making the pressures at different positions in the second chamber 104 as uniform as possible, and it becomes easier to rapidly increase the pressure in the second chamber 104 to balance with the pressure in the first chamber 102.

[0057] Furthermore, in this embodiment, the number of circular pores 212 is three, the number of the three circular pores 212 is equal, and each is 16 to 20. A plurality of the outermost pores 212 are in one-to-one correspondence with a plurality of the central pores 212, and a plurality of the central pores 212 are in one-to-one correspondence with a plurality of the innermost pores 212. The connecting lines of the centers of the three pores 212 located at the outermost, central, and innermost positions corresponding to each other are arcs, and the pore diameters of the three pores 212 gradually decrease from the outside to the inside. By arranging in this way, the gas-phase crystal growth components entering the second chamber 104 after passing through the plurality of pores 212 from the first chamber 102 can produce a swirling effect close to the outer wall of the second annular portion 220, enabling the gas-phase crystal growth components to reach the gap 106 quickly and uniformly to balance the pressures in the two chambers and reduce the flow rate of the gas-phase crystal growth components in the gap 106.

[0058] The shape and orientation of the pores 212 can also be arranged according to actual requirements. In this embodiment, the pores 212 are arranged to be inclined towards the seed crystal 110. Furthermore, the pore diameter of the pores 212 gradually decreases along the direction closer to the seed crystal 110. By inclining the pores 212 towards the seed crystal 110, the gas-phase crystal growth components can reach the gap 106 quickly after passing through the pores 212, increasing the rising speed of the pressure in the second chamber 104. On the other hand, the pressurizing effect can be obtained by the gradual decrease of the pore diameter of the pores 212, further increasing the rising speed of the pressure in the second chamber 104. At the same time, at the top of the second annular portion 220, a reverse-angle rounding 222 is installed near the outer periphery of the second chamber 104 to enable the gas-phase crystal growth components in the second chamber 104 to reach the gap 106 smoothly, realizing the pressure balance between the first chamber 102 and the second chamber 104.

[0059] The annular deflector 200 is provided with a plurality of circular pores 212 installed around the axis of the crucible 100. The pores 212 are inclined toward the seed crystal 110, and the pore diameter gradually decreases, so as to raise the gas-phase crystal growth components in the first chamber 102. At the same time, the gas-phase crystal growth components pass through the pores 212 and enter the second chamber 104, quickly reaching the gap 106 between the edge of the seed crystal 110 and the top of the annular deflector 200. Thereby, the pressures in the first chamber 102 and the second chamber 104 are quickly balanced, the flow rate of the gas-phase crystal growth components at the gap 106 is decreased, and the silicon carbide crystal 400 can be uniformly grown on the edge and the center of the seed crystal 110, ensuring the quality of the silicon carbide crystal 400.

[0060] Second Embodiment

[0061] The apparatus for growing high-quality silicon carbide crystals provided by this embodiment has basically the same overall structure, operating principle, and obtained technical effects as those of the first embodiment. The difference lies in the specific form of the pressure equalization structure.

[0062] Referring to FIG. 3, in this embodiment, the pressure equalizing structure includes silicon carbide powder 300 disposed in the second chamber 104. Such a structural form only requires disposing silicon carbide powder 300 in the first chamber 102 and also a relatively small amount of silicon carbide powder 300 in the second chamber 104 without the need to open pores 212 in the annular deflector 200. In this way, after the silicon carbide powder 300 in the first chamber 102 is heated and sublimated, it forms a gas-phase crystal growth component, flows upward to the seed crystal 110, and grows the silicon carbide crystal 400. At the same time, the silicon carbide powder 300 in the second chamber 104 is also heated and sublimated simultaneously to form a gas-phase crystal growth component (specifically, referring to FIG. 2, the dashed line with an arrow indicates the flow path of the gas-phase crystal growth component), thereby simultaneously increasing the pressure in the second chamber 104 together with the pressure in the first chamber 102, reducing the pressure difference between the first chamber 102 and the second chamber 104 as much as possible, bringing the pressures of both into a certain equilibrium state, thereby reducing the flow rate of the gas-phase crystal growth component at the gap 106, making the growth rate of the silicon carbide crystal 400 at the edge and center of the seed crystal 110 as the same as possible, further growing the silicon carbide crystal 400 uniformly on each part of the seed crystal 110, avoiding defects such as a "concave interface", and improving the growth quality of the silicon carbide crystal 400.

[0063] Summarizing the above, the high-quality silicon carbide crystal growth apparatuses provided by the above first and second embodiments of the present invention both include a crucible 100 and an annular deflector 200. On the top wall of the crucible 100, a seed crystal 110 for growing a silicon carbide crystal 400 is installed. The annular deflector 200 is installed inside the crucible 100. The bottom of the annular deflector 200 is connected to the side wall of the crucible 100, the top extends to the seed crystal 110, and there is a gap 106 between it and the edge of the seed crystal 110. The annular deflector 200, the seed crystal 110, the side wall of the crucible 100, and the bottom wall of the crucible 100 commonly enclose a first chamber 102. The annular deflector 200, the seed crystal 110, the side wall of the crucible 100, and the top wall of the crucible 100 commonly enclose a second chamber 104. The first chamber 102 and the second chamber 104 communicate with each other through the gap 106. An equalizing pressure structure for equalizing the pressures of the first chamber 102 and the second chamber 104 is installed on the annular deflector 200. By installing the equalizing pressure structure on the annular deflector 200, the pressure difference between the first chamber 102 and the second chamber 104 can be effectively reduced, and the pressures of the two chambers can be made as close as possible. In this way, the flow rate of the gas-phase crystal growth components at the gap 106 between the top of the annular deflector 200 and the edge of the seed crystal 110 can be effectively reduced, thereby making the growth rate of the silicon carbide crystal 400 at the edge of the seed crystal 110 as close as possible to the growth rate of the silicon carbide crystal 400 at the center of the seed crystal 110, further avoiding the occurrence of defects such as "concave interfaces" in the silicon carbide crystal 400 in the seed crystal 110, and improving the growth quality of the silicon carbide crystal 400.

[0064] Third Embodiment

[0065] This embodiment provides a method for growing high-quality silicon carbide crystals based on the apparatus of the first or second embodiment. Specifically,

[0066] the step of putting silicon carbide powder 300 into the crucible 100,

[0067] the step of evacuating the crucible 100 and then filling it with an inert gas,

[0068] To raise the temperature inside the crucible 100 to 2000 - 2600 °C, a step of heating the crucible 100;

[0069] To reduce the pressure inside the crucible 100 to 0.01 - 4E3 Pa, a step of re - evacuating the crucible 100;

[0070] A step where the silicon carbide powder 300 sublimes and starts to grow silicon carbide crystals 400 on the seed crystal 110;

[0071] After growing the silicon carbide crystals 400 for 10 - 300 h to raise the pressure inside the crucible 100 to 5E3 - 1E5 Pa, a step of refilling the crucible 100 with an inert gas;

[0072] After the growth of the silicon carbide crystals 400 is completed, stopping the heating of the crucible 100, and after the temperature inside the crucible 100 drops to room temperature, taking out the silicon carbide crystals 400 from the crucible 100. The method includes the above steps.

[0073] Here, the speed control of exhaust and intake is realized by a combination of a mechanical pump, a butterfly valve, and a flow meter. When putting the silicon carbide powder 300 into the crucible 100, based on the device of the first embodiment, it is only necessary to put the silicon carbide powder 300 into the first chamber 102. However, based on the device of the second embodiment, it is necessary to put the silicon carbide powder 300 into the first chamber 102 and the second chamber 104.

[0074] Example 4

[0075] This example provides a silicon carbide crystal 400 which is manufactured using the method for growing high - quality silicon carbide crystals provided by the third example, and has the characteristics of few defects and high quality.

[0076] Example 5

[0077] Referring to FIG. 4, the growth device of high - quality silicon carbide crystals provided by the present invention is improved as follows compared with the first embodiment.

[0078] A plurality of concentration adjustment through-holes 108 are provided in the side or upper part of the crucible 100 where the second chamber 104 is located.

[0079] In this embodiment, at the initial stage of crystal growth, the saturation concentrations of Si and Si2C in the gas-phase component are relatively high, and a silicon-rich crystal growth gas-phase component is clearly formed, which is considered to be disadvantageous for the high-quality growth of the silicon carbide crystal 400. On the other hand, due to the presence of the concentration adjustment through-holes 108, the excessive silicon-rich component overflows to the outside of the crucible 100, and by adjusting the ratio of carbon to silicon in the crystal growth gas-phase component in the crucible, it is advantageous for improving the growth quality of the silicon carbide crystal 400.

[0080] At the same time, the concentration adjustment through-holes 108 also play a role in guiding the flow, guiding the crystal growth gas-phase component to flow upward, and promoting the generation of the silicon carbide crystal 400.

[0081] Example 6

[0082] Referring to FIG. 5, the high-quality silicon carbide crystal growth apparatus provided by the present invention is improved as follows compared with the first embodiment.

[0083] The first annular part 210 includes two upper and lower sub-annular parts 214, the pores 212 are distributed in these two sub-annular parts 214, and when heated, the silicon carbide crystal growth gas-phase component flows through these two sub-annular parts 214 from bottom to top. The sub-annular part 214 located in the lower layer has pores 212 with larger pore diameters compared to the sub-annular part 214 in the upper layer.

[0084] As can be easily understood by those skilled in the art, the two upper and lower sub-annular parts 214 in this embodiment may not have a direct connection relationship. For example, the upper sub-annular part 214 is connected to the second annular part 220, and the lower sub-annular part 214 is connected to the side wall of the crucible 100.

[0085] The technical solution of this embodiment is to balance the concentration distribution of the crystal growth gas-phase component from the flow velocity. Specifically, at the edge of the annular deflector 200, that is, at the position of the first annular portion 210, since it is more likely to receive heat and the temperature is relatively high, the flow velocity of the crystal growth gas-phase component is relatively fast, which is disadvantageous to the equilibrium of the concentration of the crystal growth gas-phase component. Therefore, in order to constitute additional resistance to the rapidly flowing crystal growth gas-phase component, two layers of sub-annular portions 214 are provided, and by gradually decreasing the pore diameter of the pores 212 from bottom to top, the concentration distribution of the crystal growth gas-phase component in the crucible 100 is balanced.

[0086] As can be easily understood by those skilled in the art, as a further preferred form of this embodiment, the sub-annular portion 214 may be multiple layers, for example, 3 to 5 layers.

[0087] The pore diameter of the pores 212 of the uppermost sub-annular portion 214 may be made small enough until it becomes zero in order to constitute sufficient resistance.

[0088] The above are only specific embodiments of the present invention, but the claims of the present invention are not limited thereto. Those skilled in the art can easily conceive of changes or substitutions within the technical scope disclosed by the present invention, and all of them are included in the claims of the present invention.

Claims

1. A growth apparatus for high-quality silicon carbide crystals, comprising: a crucible (100) installed on a top wall with a seed crystal (110) for growing a silicon carbide crystal (400); and an annular deflector plate (200) installed in the crucible (100), wherein a bottom of the annular deflector plate (200) is connected to a side wall of the crucible (100), a top extends to the seed crystal (110), and there is a gap (106) between the annular deflector plate (200) and an edge of the seed crystal (110), and the annular deflector plate (200), the seed crystal (110), the side wall of the crucible (100), and the bottom wall of the crucible (100) commonly surround a first chamber (102), and the annular deflector plate (200), the seed crystal (110), the side wall of the crucible (100), and the top wall of the crucible (100) commonly surround a second chamber (104), the first chamber (102) communicates with the second chamber (104) through the gap (106), and an equalizing pressure structure for equalizing pressures of the first chamber (102) and the second chamber (104) is installed on the annular deflector plate (200); the equalizing pressure structure includes pores (212) formed in the annular deflector plate (200), the pores (212) communicate the first chamber (102) with the second chamber (104), the annular deflector plate (200) includes a first annular part (210) and a second annular part (220) connected at an angle, one end of the first annular part (210) away from the second annular part (220) is connected to an inner wall of the crucible (100), one end of the second annular part (220) away from the first annular part (210) extends to the seed crystal (110), and the pores (212) are formed in the first annular part (210); An apparatus characterized by the above.

2. The number of the pores (212) is plural, and the plural pores (212) are installed in one or more circles around an axis of the crucible (100). The growth apparatus for high-quality silicon carbide crystals according to Claim 1, characterized by the above.

3. The plural pores (212) are installed in a plurality of circles around the axis of the crucible (100), the plural circular pores (212) are arranged at intervals along a radial direction of the crucible (100), and any two adjacent circular pores (212) are arranged in a stagger pattern in the radial direction of the crucible (100). The growth apparatus for high-quality silicon carbide crystals according to Claim 2, characterized by the above.

4. The first annular part (210) is flat and perpendicular to the axis of the crucible (100). The outer peripheral wall of the first annular part (210) is connected to the side wall of the crucible (100). The second annular part (220) is in the shape of a hollow cylinder or a hollow frustum of a cone. The bottom of the second annular part (220) is connected to the inner peripheral wall of the first annular part (210), and the top extends to the seed crystal (110). The high-quality silicon carbide crystal growth apparatus according to claim 1, characterized in that

5. The pores (212) are installed obliquely toward the seed crystal (110), and the pore diameter of the pores (212) gradually decreases along the direction closer to the seed crystal (110). The high-quality silicon carbide crystal growth apparatus according to claim 1, characterized in that

6. The pressure equalizing structure includes silicon carbide powder (300) disposed in the second chamber (104). The high-quality silicon carbide crystal growth apparatus according to claim 1, characterized in that

7. At least one concentration adjustment through hole (108) is installed on the outer periphery of the second chamber (104) of the crucible (100). The high-quality silicon carbide crystal growth apparatus according to claim 1, characterized in that

8. The first annular part (210) includes a plurality of sub-annular parts (214) distributed vertically. The pores (212) are distributed in each sub-annular part (214). The high-quality silicon carbide crystal growth apparatus according to claim 1, characterized in that

9. Along the transport direction of the crystal growth component, the plurality of sub-annular parts (214) have pores (212) with gradually decreasing pore diameters. The high-quality silicon carbide crystal growth apparatus according to claim 8, characterized in that

10. A method for growing high-quality silicon carbide crystals, comprising: Based on the high-quality silicon carbide crystal growth apparatus according to claim 1, Putting silicon carbide powder (300) into the crucible (100); After evacuating the crucible (100), filling it with an inert gas; Heating the crucible (100) to raise the temperature inside the crucible (100) to 2000 - 2600 °C; Re-evacuating the crucible (100) to reduce the pressure inside the crucible (100) to 0.01 - 4E3 Pa; The silicon carbide powder (300) sublimes, and silicon carbide crystals (400) begin to grow on the seed crystal (110). In order to increase the pressure inside the crucible (100) to 5E3 to 1E5 Pa, after growing the silicon carbide crystal (400) for 10 to 300 h, the crucible (100) is refilled with an inert gas, and after the growth of the silicon carbide crystal (400) is completed, the heating of the crucible (100) is stopped, and after the temperature inside the crucible (100) has dropped to room temperature, the silicon carbide crystal (400) is taken out of the crucible (100), including A method characterized by the above.

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