Apparatus and method for growing high-quality silicon carbide crystals

Abstract

The present invention provides a growth apparatus and method for high-quality silicon carbide crystals, and relates to the field of silicon carbide crystal growth. The apparatus includes a crucible with a seed crystal installed at the top, a heat-insulating layer installed outside the crucible, an induction coil installed around the heat-insulating layer, and an induction heating ring installed in the heat-insulating layer and around the seed crystal. The inner wall of the induction heating ring is installed at a distance from the outer wall of the crucible and is blocked by the heat-insulating layer. The apparatus and the combined method can increase the axial temperature gradient of the crucible and improve the growth rate of silicon carbide crystals by adding an induction heating ring at the top position of the crucible, changing the magnetic field at the top position of the crucible when the induction coil is energized, reducing the heat generated at the top position of the crucible, lowering the temperature, and at the same time, reducing the radial temperature gradient of the crucible and improving the growth quality of silicon carbide crystals.

Description

Technical Field

[0001] The present invention relates to the field of silicon carbide crystal growth, and more specifically, to a growth apparatus and method 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 large bandgap, high saturated electron mobility, high 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] The methods for growing silicon carbide mainly include physical vapor transport method (PVT), liquid phase epitaxy method (LPE), chemical vapor deposition method (CVD), etc. Among them, the PVT method is the most mature method. Currently, the crystal growth apparatuses used in the PVT method generally adopt two types: induction heating and resistance heating. Among them, induction heating has the advantages of simple structure, high heating efficiency, fast heating rate, and no pollution, but there is also a problem that the temperature gradient is unreasonable and it affects the crystal growth rate and quality.

Summary of the Invention

[0004] The object of the present invention includes providing a growth apparatus and method for high-quality silicon carbide crystals that can effectively increase the axial temperature gradient to accelerate the crystal growth rate, and at the same time reduce the radial temperature gradient to improve the crystal growth quality.

[0005] The embodiments of the present invention can be realized as follows.

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

[0007] a crucible with a seed crystal installed at the top,

[0008] a heat-insulating layer installed outside the crucible,

[0009] An induction coil installed around the aforementioned heat-insulating layer,

[0010] The present invention provides an apparatus comprising an induction heating ring installed within the heat-insulating layer and surrounding the seed crystal, wherein the inner wall of the induction heating ring is installed at a distance from the outer wall of the crucible and is shielded by the heat-insulating layer.

[0011] In an optional embodiment, the crucible includes an outlet section and a crystal growth section connected in order from bottom to top, wherein the diameter of the crystal growth section is smaller than the diameter of the outlet section in order to give the crucible a stepped shape, the induction heating ring is installed around the crystal growth section, and the seed crystal is installed at the top of the crystal growth section.

[0012] In an optional embodiment, the inner diameter of the induction heating ring is constant or gradually increases along the direction from bottom to top.

[0013] In an optional embodiment, the induction heating ring includes a first annular portion and a second annular portion, the first annular portion being positioned around the seed crystal, the outer circumferential wall of the second annular portion being connected to the apex of the first annular portion, and the inner circumferential wall of the second annular portion extending toward the axis of the crucible.

[0014] In an optional embodiment, a first chamber is provided between the top of the crucible and the heat-insulating layer, and the inner circumferential wall of the second annular portion extends into the first chamber.

[0015] In an optional embodiment, the inner circumferential wall of the second annular portion extends upward above the seed crystal.

[0016] In an optional embodiment, the height of the second annular portion is constant or gradually decreases along the direction from the outer peripheral wall to the inner peripheral wall.

[0017] In an optional embodiment, the growth apparatus for high-quality silicon carbide crystals further includes an auxiliary heating ring located below the induction heating ring and positioned around the crucible, wherein the inner wall of the auxiliary heating ring is spaced apart from the outer wall of the crucible, and a second chamber is provided between the lower surface of the crucible and the heat-insulating layer, with the auxiliary heating ring located within the second chamber.

[0018] According to a second aspect, the present invention relates to a method for growing high-quality silicon carbide crystals, based on a high-quality silicon carbide crystal growth apparatus provided in any one of the above embodiments,

[0019] The process involves placing silicon carbide powder into the crucible,

[0020] After evacuating the crucible, it is filled with an inert gas.

[0021] To raise the temperature inside the crucible to 2000-2600°C, the induction coil is energized to heat the crucible,

[0022] In order to reduce the pressure inside the crucible to 0.01 to 4E3Pa, the crucible is evacuated again,

[0023] The silicon carbide powder sublimes and begins to grow silicon carbide crystals on the seed crystal,

[0024] In order to increase the pressure inside the crucible to 5E3~1E5Pa, the silicon carbide crystals are grown for 10~300 hours, and then the crucible is refilled with inert gas.

[0025] The present invention further provides a method comprising cutting the induction coil after the growth of the silicon carbide crystals is complete, and removing the silicon carbide crystals from the crucible after the temperature inside the crucible has decreased to room temperature.

[0026] According to a third aspect, the present invention further provides a silicon carbide crystal manufactured by using the method for growing a high-quality silicon carbide crystal of the foregoing embodiment.

[0027] The beneficial effects of the examples of the present invention include the following. For example,

[0028] This growth apparatus for high-quality silicon carbide crystals includes a crucible with a seed crystal installed at the top, a heat-insulating layer installed outside the crucible, an induction coil installed around the heat-insulating layer, and an induction heating ring installed inside the heat-insulating layer and around the seed crystal. The inner wall of the induction heating ring is installed at an interval from the outer wall of the crucible and is blocked by the heat-insulating layer. By adding an induction heating ring at the top position of the crucible, the magnetic field at the top position of the crucible when the induction coil is energized is changed, the heat generated at the top position of the crucible is reduced, the temperature is lowered, thereby increasing the temperature gradient in the axial direction of the crucible, improving the growth rate of the silicon carbide crystal, and at the same time reducing the temperature gradient in the radial direction of the crucible, and improving the growth quality of the silicon carbide crystal.

[0029] Correspondingly, this method for growing a high-quality silicon carbide crystal can improve the growth rate and quality of the silicon carbide crystal because the above device is used.

Brief Description of the Drawings

[0030] To more clearly illustrate the technical solution of the examples of the present invention, the drawings required for use in the examples are briefly described below. However, since the following drawings only show some examples of the present invention, they should not be regarded as limiting the scope. It should be understood by those skilled in the art that other related drawings can be obtained according to these drawings without creative effort. [Figure 1] It is a configuration diagram of a growth apparatus for high-quality silicon carbide crystals provided by the first example of the present invention. [Figure 2] It is a configuration diagram of another growth apparatus for high-quality silicon carbide crystals provided by the first example of the present invention. [Figure 3]This is a diagram showing the configuration of a growth apparatus for high-quality silicon carbide crystals provided according to a second embodiment of the present invention. [Figure 4] This is a diagram showing the configuration of another high-quality silicon carbide crystal growth apparatus provided by a second embodiment of the present invention. [Figure 5] This is a diagram showing the configuration of a growth apparatus for high-quality silicon carbide crystals provided according to a third embodiment of the present invention.

[0031] Symbols in the drawing: 100-crucible, 102-discharge section, 104-crystal growth section, 110-seed crystal, 200-insulating layer, 300-induction coil, 400-induction heating ring, 410-first annular section, 420-second annular section, 500-first chamber, 600-second chamber, 700-auxiliary heating ring, 800-silicon carbide powder. [Modes for carrying out the invention]

[0032] To further clarify the object, technical solution, and advantages of the embodiments of the present invention, the technical solution of the embodiments of the present invention will be clearly and fully described below with reference to the drawings of the embodiments of the present invention. The embodiments described are some, but not all, embodiments of the present invention. In general, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in a variety of different configurations.

[0033] Accordingly, the following detailed description of embodiments of the present invention provided by the drawings is not intended to limit the claimed scope of the invention, but represents only selected embodiments of the invention. Any other embodiments that can be obtained by those skilled in the art based on the embodiments of the invention without requiring any creative effort are included within the scope of the claims of the invention.

[0034] Similar symbols and letters indicate similar items in the following drawings; therefore, it should be noted that once an item is defined in one drawing, it is not necessary to further define and explain it in subsequent drawings.

[0035] In describing the present invention, terms such as "up," "down," "inside," and "outside" are used to facilitate and simplify the description of the invention, when the indicated orientation or positional relationship is the orientation or positional relationship shown in the drawings, or the orientation or positional relationship that is conventionally arranged when the product of the invention is used. This is not intended to indicate or imply that the referred device or element has a particular orientation, is configured in a particular orientation, or must be operated in a particular orientation, and therefore should not be understood as a limitation of the invention.

[0036] Furthermore, when terms such as "first" and "second" appear, they are used solely for the purpose of differentiation and are not intended to indicate or suggest relative importance.

[0037] The features of the embodiments of the present invention can be combined with each other, as long as they do not contradict each other.

[0038] Currently, there are mainly two types of heating methods used in silicon carbide crystal growth: induction heating and resistance heating. Induction heating utilizes the electromagnetic induction effect, using the crucible itself as a heat source to supply heat for the sublimation of silicon carbide powder inside the crucible. It has advantages such as a simple structure, high heating efficiency, fast heating rate, and no contamination. However, due to the skin effect, the heat generated by induction heating is mainly concentrated on the outer surface of the crucible. Therefore, in the silicon carbide crystal growth process, if the axial temperature gradient is too small and the radial temperature gradient is too large, the axial temperature gradient will affect the growth rate of the silicon carbide crystal, and if the radial temperature gradient is too large, the internal stress of the silicon carbide crystal will increase, making it easier for defects such as dislocations to occur, and at the same time increasing the risk of cracking in the silicon carbide crystal, leading to quality problems.

[0039] Resistive heating is a method of heating an object by utilizing the thermal energy generated by the Joule effect when an electric current flows through a resistor. Taking a graphite heater as an example, it generates heat after passing direct or alternating current through it, and then transfers heat to the crucible mainly through thermal radiation and thermal convection. Since the heater does not directly contact the crucible, the heating effect is more uniform, and the radial temperature gradient for crystal growth is clearly smaller than that of induction heating. However, the structure is complex, the cost is high, and the problem of ignition is more likely to occur.

[0040] Based on the above, the present invention provides an apparatus and method using induction heating that retains the advantages of induction heating while simultaneously improving crystal growth quality and accelerating the crystal growth rate. This high-quality silicon carbide crystal growth apparatus adds an induction heating ring to the top of the crucible, thereby changing the magnetic field at the top of the crucible when the induction coil is energized. This reduces the heat generated at the top of the crucible, lowers the temperature, increases the temperature difference between the middle and bottom of the crucible, and increases the axial temperature gradient of the crucible, promoting the rapid growth of silicon carbide crystals and accelerating the growth rate. At the same time, the temperature of the outer circumference of the top of the crucible decreases, inevitably reducing the radial temperature difference at the top of the crucible. This reduces the radial temperature gradient inside the crucible, making it easier for silicon carbide crystals to grow uniformly in the radial direction, thus improving the growth quality.

[0041] The following describes in detail, with reference to the drawings, the structure, principle, effect, and corresponding steps of the high-quality silicon carbide crystal growth apparatus provided by the present invention.

[0042] First Example

[0043] Referring to Figure 1 or Figure 2, the high-quality silicon carbide crystal growth apparatus provided by the present invention includes a crucible 100, a heat insulating layer 200, an induction coil 300, and an induction heating ring 400.

[0044] Here, the crucible 100 is made of graphite and generates heat when current is passed through the induction coil 300. A seed crystal 110 is placed on the inner wall of the top of the crucible 100. The method of fixing the seed crystal 110 may be adhesive, clamping, etc., and is not specifically limited in this embodiment.

[0045] In this embodiment, the crucible 100 includes an outlet section 102 and a crystal growth section 104 connected in order from bottom to top. To give the crucible 100 a stepped shape, the diameter of the crystal growth section 104 is smaller than the diameter of the outlet section 102. The crystal growth section 104 constitutes the top of the crucible 100, the outlet section 102 constitutes the middle and lower parts of the crucible 100, and the seed crystal 110 is placed at the top of the crystal growth section 104 (i.e., the crucible lid). By using such a stepped structure with a smaller top and a larger bottom, when the crucible 100 is heated, the temperature of the outlet section 102 is higher than the temperature of the crystal growth section 104, thereby improving the axial temperature gradient of the crucible 100 and increasing the growth rate of silicon carbide crystals.

[0046] The heat-insulating layer 200 is installed on the outside of the crucible 100. More specifically, the heat-insulating layer 200 covers the outer wall of the crucible 100 in order to slow down heat loss from the crucible 100 as much as possible and provide the temperature environment necessary for the growth of silicon carbide crystals inside the crucible 100. A first chamber 500 is installed between the top of the crucible 100 and the heat-insulating layer 200. More specifically, the outer surface of the top of the crystal growth section 104 does not directly contact and bond with the heat-insulating layer 200, but rather forms the first chamber 500 at a certain distance. By installing the first chamber 500, heat is uniformly transferred to the top of the crystal growth section 104, thereby reducing the radial temperature gradient of the crystal growth section 104 and improving the growth quality of the silicon carbide crystals.

[0047] The induction heating ring 400 is made of the same material as the crucible 100, which is also graphite. The induction heating ring 400 is installed inside the heat insulation layer 200 and around the seed crystal 110, that is, the induction heating ring 400 is installed around the crystal growth section 104. The inner wall of the induction heating ring 400 is spaced apart from the outer wall of the crucible 100 and is shielded by the heat insulation layer 200, that is, the induction heating ring 400 does not directly contact the outer wall of the crucible 100, and the heat insulation layer 200 is locally filled between them. Since the diameter of the crystal growth section 104 is smaller than the diameter of the discharge section 102, the distance between the inner wall of the induction heating ring 400 and the outer wall of the crystal growth section 104 becomes relatively larger, the heat insulation layer 200 between them becomes relatively thicker, the heat insulation effect is improved, and the transfer of heat from the induction heating ring 400 to the crystal growth section 104 of the crucible 100 can be effectively blocked.

[0048] Furthermore, the axis of the induction heating ring 400 coincides with the axis of the crucible 100, and in this way each part of the induction heating ring 400 is at the same distance as the radially corresponding part of the outer wall of the crucible 100. This allows for a uniform change in the magnetic field at different circumferential positions at the top of the crucible 100, and further allows for a uniform reduction in circumferential heat at the top of the crucible 100, thereby uniformly lowering the temperature. In this way, the silicon carbide crystals on the seed crystal 110 can grow uniformly in different circumferential parts, improving the growth quality.

[0049] It may be necessary to provide a specific structure for the induction heating ring 400. Referring further to Figure 1, in this embodiment, the inner diameter of the induction heating ring 400 is constant along the direction from bottom to top, that is, the entire induction heating ring 400 has a hollow cylindrical shape, and its extension direction is parallel to the extension direction of its own axis or the axis of the crucible 100. To further explain, referring to Figure 2, in this embodiment, the inner diameter of the induction heating ring 400 can also be gradually increased along the direction from bottom to top. That is, the entire induction heating ring 400 takes on the shape of an inverted hollow truncated ring, and its extension direction is at an angle with its own axis or the axis of the crucible 100. The specific magnitude of the angle can be set as needed, for example, 5 to 15°. In this way, the portion of the crucible 100 surrounded by the induction heating ring 400 can gradually reduce the generated heat and gradually lower its temperature along the direction from bottom to top. That is, the portion of the crucible 100 surrounded by the induction heating ring 400 also has a temperature gradient in the axial direction. In this way, the axial temperature gradient of the entire crucible 100 can be further improved, thereby increasing the growth rate of silicon carbide crystals on the seed crystal 110.

[0050] The induction coil 300 is placed around the heat-insulating layer 200 so that it is connected to a power source and current can flow through it, thereby generating heat in the crucible 100 and the induction heating ring 400 using the electromagnetic induction effect.

[0051] The operating principle and process of this high-quality silicon carbide crystal growth apparatus are specifically as follows:

[0052] When current is passed through the induction coil 300, the electromagnetic induction effect generates heat in the crucible 100, which itself becomes a heat source. This causes the silicon carbide powder 800 inside the crucible 100 to sublimate, forming a gas-phase crystal growth component (mainly SimCn). After the gas-phase crystal growth component rises, silicon carbide crystals are formed on the seed crystal 110. On the other hand, by installing the induction heating ring 400, the magnetic field at the top of the crucible 100 can be changed. The heat generated at the top of the crucible 100 is reduced compared to the middle and lower parts where the induction heating ring 400 is not installed. That is, the heat generated in the crystal growth section 104 is reduced compared to the discharge section 102 (due to the skin effect of induction heating, the eddy currents induced at the top of the hot field are mainly in the induction heating ring 400, so the Joule heat generated in the induction heating ring 400 is much greater than the Joule heat in the region where the crystal growth section 104 is located). The space between 400 and the crystal growth section 104 is blocked by the heat-insulating layer 200, and the heat generated in the induction heating ring 400 is significantly reduced when it is transferred to the crystal growth section 104. Therefore, the heat in the crystal growth section 104 mainly originates from the heat transfer in the discharge section 102, and the heat generated in the crystal growth section 104 is inevitably reduced. As a result, the temperature of the crystal growth section 104 is lower than the temperature of the discharge section 102, increasing the axial temperature difference of the crucible 100, that is, increasing the axial temperature gradient of the crucible 100, and further effectively increasing the growth rate of silicon carbide crystals on the seed crystal 110. At the same time, the decrease in temperature of the outer circumference of the top of crucible 100 inevitably reduces the temperature difference between different radial parts at the top of crucible 100, thereby reducing the radial temperature gradient of crucible 100, allowing for uniform growth of the different radial parts of the silicon carbide crystal and improving the growth quality of the silicon carbide crystal.

[0053] This high-quality silicon carbide crystal growth apparatus reduces the heat generated at the top of the crucible 100 by changing the magnetic field at the top of the crucible 100, thereby lowering the temperature at the top of the crucible 100 to a lower temperature than the temperature in the middle and lower parts of the crucible 100. In other words, the temperature of the crystal growth section 104 is lower than the temperature of the discharge section 102. In this way, the axial temperature gradient of the crucible 100 is increased, thereby effectively accelerating the growth rate of the silicon carbide crystals. At the same time, the radial temperature gradient of the crucible 100 is reduced, thereby improving the growth quality of the silicon carbide crystals.

[0054] Second Example

[0055] The overall structure, operating principle, and acquired technical effects of the high-quality silicon carbide crystal growth apparatus provided by this embodiment are basically the same as those of the first embodiment, the only difference being the specific structure of the induction heating ring 400.

[0056] Referring to Figure 3 or Figure 4, in this embodiment, the induction heating ring 400 includes a first annular portion 410 and a second annular portion 420, the first annular portion 410 being installed around the seed crystal 110, that is, the first annular portion 410 being installed around the crystal growth portion 104. The axis of the first annular portion 410 coincides with the axis of the crucible 100, and the inner wall of the first annular portion 410 is installed at a distance from the outer wall of the crucible 100 and is blocked by the heat insulation layer 200.

[0057] The axis of the second annular portion 420 also coincides with the axis of the crucible 100, and the entire second annular portion 420 is located above the crystal growth portion 104. The outer peripheral wall of the second annular portion 420 is connected to the top of the first annular portion 410, and the inner peripheral wall of the second annular portion 420 extends toward the axis of the crucible 100, so that the induction heating ring 400 has an "L" shape in which the cross section at any position in the circumferential direction is substantially inverted, the first annular portion 410 faces the circumferential surface of the crystal growth portion 104 in the radial direction, and the second annular portion 420 faces the end face of the crystal growth portion 104 in the axial direction.

[0058] The relative positions of the first annular portion 410 and the second annular portion 420 can be set as needed. Referring further to Figure 3, in this embodiment, the first annular portion 410 is hollow cylindrical and its extension direction is parallel to its own axis or the axis of the crucible 100, while the inner circumferential wall of the second annular portion 420 extends into the first chamber 500 and also extends upward toward the seed crystal 110. Along the direction from the outer circumferential wall of the second annular portion 420 toward the inner circumferential wall of the second annular portion 420, the height of the second annular portion 420 is constant, that is, the second annular portion 420 extends horizontally and its extension direction is perpendicular to its own axis or the axis of the crucible 100.

[0059] When an induction heating ring 400 with such a structure is used, its second annular portion 420 can adjust the heat transfer effect from the first annular portion 410 to the crystal growth portion 104. When the first annular portion 410 becomes the first heat source, the second annular portion 420 becomes the second heat source. By setting the shape and size of the second annular portion 420, the radial temperature gradient of the crystal growth portion 104 can be adjusted. Maintaining a small temperature gradient in the crystal growth portion 104 theoretically improves the growth quality of silicon carbide crystals as the radial temperature gradient is smaller. However, when the radial temperature gradient becomes small to a certain extent, the crystal growth portion 104 needs to maintain a constant radial temperature gradient as required in practice to better control the growth shape of the silicon carbide crystals, thereby further improving the growth quality of the silicon carbide crystals.

[0060] Further explanation will be provided in Figure 4. In this embodiment, the second annular portion 420 can also exhibit an inverted hollow trapezoidal shape, and its extension direction has an angle of less than 90° with its own axis or the axis of the crucible 100, for example, 75° to 85°. In this way, the radial temperature gradient of the crystal growth portion 104 can be adjusted as needed to control the growth shape of the silicon carbide crystal and further improve the growth quality of the silicon carbide crystal.

[0061] The method of connecting the first annular section 410 and the second annular section 420 can also be provided as needed. In this embodiment, the first annular section 410 and the second annular section 420 are separate structures and are connected by a connecting member. In other embodiments, the two can be integrally molded.

[0062] Third Example

[0063] The overall structure, operating principle, and acquired technical effects of the high-quality silicon carbide crystal growth apparatus provided by this embodiment are basically the same as those of the first or second embodiment, the difference being that the apparatus provided by this embodiment further includes an auxiliary heating ring 700, and the diameter of the crucible 100 is the same from bottom to top and not stepped.

[0064] Referring to Figure 5, in this embodiment, the auxiliary heating ring 700 is located below the induction heating ring 400 and is installed around the crucible 100, with the inner wall of the auxiliary heating ring 700 spaced apart from the outer wall of the crucible 100. The material of the auxiliary heating ring 700 is the same as that of the crucible 100 or the induction heating ring 400, and is also graphite, in order to generate heat when the induction coil 300 is energized. The number of auxiliary heating rings 700 can be set as needed, and in this embodiment, only one auxiliary heating ring 700 is installed, and its bottom extends to a position lower than the bottom of the crucible 100.

[0065] In other embodiments, the auxiliary heating rings 700 may be two or three or more, and the multiple auxiliary heating rings 700 are installed at intervals along the axis of the crucible 100. The multiple auxiliary heating rings 700 work together to achieve independent heating of different parts of the crucible 100 in the axial direction, achieving an effect similar to independent heating using multiple heaters. This avoids the drawbacks of conventional resistance heating, such as the complex structure of the device and its susceptibility to ignition in low-pressure environments, resulting in high heating efficiency and cost reduction.

[0066] Furthermore, in order to improve the uniformity of heating in the lower part of the crucible 100, in this embodiment, a second chamber 600 is installed between the lower surface of the crucible 100 and the heat-insulating layer 200. The second chamber 600 surrounds the outer surface of the lower side wall and the outer surface of the bottom wall of the crucible 100, and the auxiliary heating ring 700 is located inside the second chamber 600 and fixed by a mounting bracket (not shown). With this installation, the characteristic of low thermal conductivity of gas can be utilized, and the heat generated in the auxiliary heating ring 700 can be uniformly transferred to different parts of the middle and lower parts of the crucible 100 via the gas in the second chamber 600 (mainly Ar, N2, gas phase crystal growth components, etc.), thereby improving the uniformity of temperature in different parts of the middle and lower parts of the crucible 100, reducing the radial temperature gradient of the crucible 100, and improving the growth quality of silicon carbide crystals. At the same time, this setup can improve the heating effect on the silicon carbide powder 800 near the center of the crucible 100, thereby improving the utilization rate of the silicon carbide powder 800.

[0067] It should be explained that in other embodiments, in order to further improve the heating effect on the central position of the bottom of the crucible 100, auxiliary heating plates (not shown) can be installed at intervals below the bottom of the crucible 100, thereby increasing the temperature at the central position of the bottom of the crucible 100, further improving the heating effect on the silicon carbide powder 800 at the central position of the crucible 100, and increasing the utilization rate of the silicon carbide powder 800.

[0068] Furthermore, it should be explained that in order to further increase the axial temperature gradient of the crucible 100, the crucible 100 in this embodiment may have a stepped shape as in the first or second embodiment, and this can be specifically determined according to the actual requirements.

[0069] Fourth Embodiment

[0070] Examples of the present invention relate to a method for growing high-quality silicon carbide crystals, specifically based on the apparatus provided in the first, second, or third example,

[0071] The steps include placing 800 units of silicon carbide powder into a crucible 100,

[0072] The steps include: evacuating the crucible 100 and then filling it with inert gas;

[0073] In order to raise the temperature inside the crucible 100 to 2000-2600°C, the induction coil 300 is energized to heat the crucible 100,

[0074] In order to reduce the pressure inside crucible 100 to 0.01~4E3Pa, the crucible 100 is evacuated again.

[0075] The silicon carbide powder 800 sublimes, and the silicon carbide crystal begins to grow on the seed crystal 110.

[0076] In order to increase the pressure inside crucible 100 to 5E3~1E5Pa, the silicon carbide crystals are grown for 10~300 hours, and then the crucible 100 is refilled with inert gas.

[0077] The present invention provides a method comprising the steps of cutting the induction coil 300 after the growth of silicon carbide crystals is complete, and removing the silicon carbide crystals from the crucible 100 after the temperature inside the crucible has decreased to room temperature.

[0078] Here, exhaust and intake speed control is achieved through a combination of mechanical pumps, butterfly valves, and flow meters.

[0079] Fifth example:

[0080] The embodiments of the present invention provide silicon carbide crystals (i.e., ingots) produced using the high-quality silicon carbide crystal growth method provided in the fourth embodiment, which are characterized by having few defects and high quality.

[0081] The above are merely specific embodiments of the present invention, but the scope of the claims of the present invention is not limited thereto. Any modification or substitution that can be easily conceived by a person skilled in the art within the scope of the art disclosed by the present invention is included within the scope of the claims of the present invention.

Claims

1. A growth apparatus for high-quality silicon carbide crystals, A crucible (100) with a seed crystal (110) placed at the top, An insulating layer (200) installed on the outside of the crucible (100), An induction coil (300) is installed around the aforementioned heat-insulating layer (200), The system includes an induction heating ring (400) installed within the heat-insulating layer (200) and surrounding the seed crystal (110), The inner wall of the induction heating ring (400) is installed at a distance from the outer wall of the crucible (100) and is shielded from the heat insulation layer (200). The induction heating ring (400) includes a first annular portion (410) and a second annular portion (420), the first annular portion (410) being positioned around the seed crystal (110), the outer peripheral wall of the second annular portion (420) being connected to the top of the first annular portion (410), and the inner peripheral wall of the second annular portion (420) extending toward the axis of the crucible (100). The crucible (100) includes a discharge section (102) and a crystal growth section (104) connected in order from bottom to top, and in order to make the crucible (100) stepped, the diameter of the crystal growth section (104) is smaller than the diameter of the discharge section (102), the induction heating ring (400) is installed around the crystal growth section (104), and the seed crystal (110) is installed at the top of the crystal growth section (104). A first chamber (500) is installed between the top of the crucible (100) and the heat-insulating layer (200), and the inner circumferential wall of the second annular portion (420) extends into the first chamber (500). A growth apparatus for high-quality silicon carbide crystals, characterized by the following features.

2. Along the direction from bottom to top, the inner diameter of the induction heating ring (400) is constant or gradually increases. The growth apparatus for high-quality silicon carbide crystals according to feature 1.

3. The inner circumferential wall of the second annular portion (420) extends above the seed crystal (110), The growth apparatus for high-quality silicon carbide crystals according to feature 1.

4. Along the direction from the outer peripheral wall to the inner peripheral wall, the height of the second annular portion (420) is constant or gradually decreases. The growth apparatus for high-quality silicon carbide crystals according to feature 1.

5. The system further includes an auxiliary heating ring (700) located below the induction heating ring (400) and installed around the crucible (100), wherein the inner wall of the auxiliary heating ring (700) is spaced apart from the outer wall of the crucible (100), and a second chamber (600) is installed between the lower surface of the crucible (100) and the heat-insulating layer (200), and the auxiliary heating ring (700) is located within the second chamber (600). The growth apparatus for high-quality silicon carbide crystals according to feature 1.

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