Radial temperature gradient adjustable crystal growth apparatus and method

Abstract

This invention provides a radially temperature-adjustable crystal growth apparatus and method, relating to the field of silicon carbide crystal growth technology, to improve the technical problem of inconvenient radial temperature gradient adjustment of the crystal to be grown in the prior art. It includes a heating furnace, a crucible, and a radial temperature gradient adjustment device; the crystal to be grown and silicon carbide powder are respectively arranged inside the crucible; the radial temperature gradient adjustment device is disposed on the top wall, and includes a driving component and multiple heat reflectors connected to the driving component; the multiple heat reflectors selectively move above the crystal to be grown under the action of the driving component to reflect at least a portion of the heat above the crystal to be grown to the crystal, thereby adjusting the radial temperature gradient at the growth interface of the crystal. This invention can effectively reduce crystal defects, improve substrate yield, and obtain the desired crystal morphology.

Description

Technical Field

[0001] This invention relates to the field of silicon carbide crystal growth technology, and more specifically, to a radially temperature gradient adjustable crystal growth apparatus and method. Background Technology

[0002] In the physical vapor transport method for silicon carbide crystals, the radial temperature gradient at the crystal growth interface (i.e., the radial temperature gradient) directly determines the growth quality and morphology of the crystal. At different stages of the crystal growth process, the radial temperature gradient needs to be adjusted to improve the crystal quality and meet the requirements for different crystal morphologies.

[0003] In the prior art, the radial temperature gradient of the crystal to be grown is usually achieved by adjusting the thickness of the insulation layer on the side wall of the crucible. The effect is not ideal and it is impossible to achieve dynamic adjustment of the radial temperature gradient during the crystal growth process. Summary of the Invention

[0004] The present invention aims to provide a radially temperature gradient adjustable crystal growth apparatus and method to improve the technical problem of inconvenient radial temperature gradient adjustment of the crystal to be grown in the prior art.

[0005] The embodiments of the present invention can be implemented as follows:

[0006] In a first aspect, the present invention provides a radially temperature gradient adjustable crystal growth apparatus, comprising:

[0007] A heating furnace, the heating furnace including opposing side walls and a top wall, the side walls and the top wall defining a heating space;

[0008] A crucible is disposed within the heating space, and the crucible contains the crystal to be grown and silicon carbide powder, respectively.

[0009] A radial temperature gradient adjustment device is disposed on the top wall. The radial temperature gradient adjustment device includes a driving component and a plurality of heat reflectors connected to the driving component. Under the action of the driving component, the plurality of heat reflectors selectively move to the top of the crystal to be grown, so as to reflect at least part of the heat above the crystal to be grown to the crystal, thereby adjusting the radial temperature gradient at the growth interface of the crystal to be grown.

[0010] In an optional embodiment, the plurality of heat reflectors include a first heat reflector and a second heat reflector;

[0011] The first heat reflector is a disc-shaped heat reflector, and the second heat reflector is a ring-shaped heat reflector.

[0012] In an optional embodiment, the plurality of heat reflectors further includes a third heat reflector;

[0013] The third heat reflector is a disc-shaped heat reflector, and the radius of the third heat reflector is smaller than that of the first heat reflector.

[0014] In an optional embodiment, the second heat reflector includes a non-heat reflective region and a heat reflective region surrounding the non-heat reflective region;

[0015] The radius corresponding to the non-heat-reflective region is r The radius corresponding to the heat reflection area is R ,in, .

[0016] In an optional embodiment, the radial temperature gradient adjustment device further includes a first fixed platform and a second fixed platform for fixing the drive assembly and capable of driving the drive assembly to move up and down axially.

[0017] The second fixed platform is equipped with multiple temperature detection devices; the multiple temperature detection devices are used to detect the radial temperature gradient at the growth interface of the crystal to be grown.

[0018] Monitoring holes are provided on the second fixed platform, the top wall, the first heat reflector, the second heat reflector, and the third heat reflector. The temperature detection device detects the radial temperature gradient at the growth interface of the crystal to be grown through the monitoring holes.

[0019] In an optional implementation, the driving component includes a first driving unit, a second driving unit, and a third driving unit;

[0020] The first drive unit includes a first drive motor, a first drive rod connected to the first drive motor, and a first rotating component connected to the first drive rod;

[0021] The second drive unit includes a second drive motor, a second drive rod connected to the second drive motor, and a second rotating component connected to the second drive rod;

[0022] The third drive unit includes a third drive motor, a third drive rod connected to the third drive motor, and a third rotating component connected to the third drive rod;

[0023] The first heat reflector, the second heat reflector, and the third heat reflector are respectively connected to the first rotating component, the second rotating component, and the third rotating component via transmission.

[0024] In an optional embodiment, the first rotating member, the second rotating member, and the third rotating member are coaxially arranged and sequentially sleeved and connected from the inside to the outside.

[0025] In an optional embodiment, the crucible includes a crucible lid for placing the crystal to be grown, and the crucible lid has a thinning portion on the side face away from the crystal to be grown.

[0026] The location of the thinning section corresponds to the position of the facet of the crystal to be grown, so as to increase the heat dissipation at the facet of the crystal to be grown.

[0027] In a second aspect, the present invention provides a radially temperature gradient adjustable crystal growth method, based on the radially temperature gradient adjustable crystal growth apparatus described in any of the foregoing embodiments, comprising:

[0028] The crystal to be grown and silicon carbide powder are arranged in the crucible, and the crucible is placed in a heating furnace. A radial temperature gradient adjustment device is set on the heating furnace.

[0029] The heating furnace is started to heat the crucible so that the crystal to be grown enters the crystal growth stage. During the crystal growth stage, the temperature of the middle and / or edge of the growth interface of the crystal to be grown is adjusted in real time by the radial temperature gradient adjustment device to adjust the crystal growth rate or obtain different crystal morphologies.

[0030] In an optional implementation, the method for adjusting the crystal growth rate is as follows:

[0031] The heat reflector is moved to the top of the growth interface of the crystal to be grown, and the heat above the crystal to be grown is reflected to the middle and edge of the growth interface of the crystal to be grown. The middle and edge of the growth interface of the crystal to be grown are kept warm at the same time to reduce the growth rate of the crystal.

[0032] The methods for obtaining different crystal morphologies are as follows:

[0033] The heat reflector is moved to a position above the growth interface of the crystal to be grown, reflecting the heat above the crystal to the center of the growth interface, thus keeping the center of the crystal warm and reducing the convexity of the crystal center; or

[0034] The heat reflector is moved to the top of the growth interface of the crystal to be grown, and the heat above the crystal to be grown is reflected to the edge of the growth interface of the crystal to be grown, so as to keep the edge of the growth interface of the crystal to be grown warm and increase the convexity of the middle part of the crystal.

[0035] The beneficial effects of the radially temperature gradient adjustable crystal growth apparatus and method provided in the embodiments of the present invention include:

[0036] The radial temperature gradient adjustable crystal growth apparatus and method provided by the present invention, by setting a radial temperature gradient adjustment device in the heating furnace, can adjust the radial temperature gradient at the growth interface of the crystal to be grown in real time during the silicon carbide crystal growth process. In this way, the radial temperature gradient at the growth interface of the crystal to be grown can be dynamically adjusted according to different stages of the crystal growth process, which can effectively reduce crystal defects, improve substrate yield, and obtain the desired crystal morphology. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the radial temperature gradient adjustable crystal growth apparatus provided in Embodiment 1.

[0039] Figure 2 This is a schematic diagram of the radial temperature gradient adjustment device in the radial temperature gradient adjustable crystal growth apparatus provided in this embodiment 1;

[0040] Figure 3 This is a schematic diagram of the structure of the first heat reflector in the radially temperature gradient adjustable crystal growth apparatus provided in this embodiment.

[0041] Figure 4 This is a schematic diagram of the structure of the second heat reflector in the radially temperature gradient adjustable crystal growth apparatus provided in this embodiment 1;

[0042] Figure 5 This is a schematic diagram of the structure of the third heat reflector in the radially temperature gradient adjustable crystal growth apparatus provided in this embodiment 1;

[0043] Figure 6 This is a schematic diagram of the radial temperature gradient adjustable crystal growth apparatus provided in this embodiment under its first working state.

[0044] Figure 7 This is a schematic diagram of the radial temperature gradient adjustable crystal growth apparatus provided in Embodiment 1 in its second working state;

[0045] Figure 8 This is a schematic diagram of the radial temperature gradient adjustable crystal growth apparatus provided in Embodiment 1 in its third working state;

[0046] Figure 9This is a schematic diagram of the radial temperature gradient adjustable crystal growth apparatus provided in Embodiment 1 in its fourth operating state;

[0047] Figure 10 This is a schematic diagram of the radial temperature gradient adjustable crystal growth apparatus provided in Embodiment 1 in its fifth working state;

[0048] Figure 11 This is a schematic diagram of the radial temperature gradient adjustable crystal growth apparatus provided in Embodiment 1 in its sixth working state;

[0049] Figure 12 This is a schematic diagram of the small facet region in the radially temperature gradient adjustable crystal growth apparatus provided in Embodiment 2;

[0050] Figure 13 This is a schematic diagram of the radial temperature gradient adjustable crystal growth apparatus provided in Embodiment 2.

[0051] Figure 14 This is a flowchart of the radial temperature gradient adjustable crystal growth method provided in Embodiment 3.

[0052] Icons: 100 - Heating furnace; 110 - Side wall; 120 - Top wall; 130 - Heating space; 140 - Heating element;

[0053] 200 - Crucible; 210 - Crystal to be grown; 220 - Silicon carbide powder; 230 - Crucible lid; 240 - Thinned section; 250 - Stepped section;

[0054] 300 - Radial temperature gradient adjustment device; 310 - Drive assembly; 311 - First drive unit; 3111 - First drive motor; 3112 - First drive rod; 3113 - First rotating component; 312 - Second drive unit; 3121 - Second drive motor; 3122 - Second drive rod; 3123 - Second rotating component; 313 - Third drive unit; 3131 - Third drive motor; 3132 - Third drive rod; 3133 - Third rotating component;

[0055] 320 - Heat reflector; 321 - First heat reflector; 322 - Second heat reflector; 3221 - Non-heat reflective area; 3222 - Heat reflective area; 323 - Third heat reflector; 330 - First fixed platform; 340 - Second fixed platform;

[0056] 400 - Temperature sensing element; 500 - Monitoring hole; 600 - Small facet. Detailed Implementation

[0057] 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 with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0058] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0059] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0060] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are 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, and therefore should not be construed as a limitation of this invention.

[0061] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0062] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0063] In the physical vapor transport method for silicon carbide crystals, the radial temperature gradient at the crystal growth interface directly determines the crystal growth quality and morphology. At different stages of crystal growth, the radial temperature gradient needs to be adjusted to improve crystal quality and meet varying requirements for crystal morphology. For example, during substrate dicing, the thickness of the substrate to be diced varies depending on the requirements; crystals with a central convex shape are suitable for dicing thicker substrates, while crystals with a central concave shape are suitable for dicing thinner substrates.

[0064] The following describes in detail the steps, implementation principle, and technical effects of the radial temperature gradient adjustable crystal growth method provided by the present invention, along with the overall structure, working principle, and technical effects of the supporting radial temperature gradient adjustable crystal growth device, through embodiments and in conjunction with the accompanying drawings.

[0065] Example 1:

[0066] Please see Figure 1 This embodiment provides a radially temperature gradient adjustable crystal growth apparatus, including a furnace 100, a crucible 200 disposed within the furnace 100, and a radial temperature gradient adjusting device 300 disposed on the furnace 100. The furnace 100 includes opposing side walls 110 and a top wall 120, defining a heating space 130 between the side walls 110 and the top wall 120. A heating element 140 for heating the crucible 200 is disposed within the heating space 130.

[0067] In this embodiment, the heating furnace 100 is used to provide the thermal environment required for crystal growth, and the crucible 200 is used to provide the growth environment required for crystal growth. The crucible 200 is disposed in the heating space 130 and can be heated by the heating element 140.

[0068] Furthermore, the crucible 200 contains the crystal to be grown 210 and silicon carbide powder 220; the radial temperature gradient adjustment device 300 is disposed on the top wall 120. The radial temperature gradient adjustment device 300 includes a driving component 310 and multiple heat reflectors 320 connected to the driving component 310. The multiple heat reflectors 320 can move above the crystal to be grown 210 under the action of the driving component 310, so as to reflect part of the heat above the crystal to be grown 210 to the growth interface of the crystal to be grown 210. It can be understood that the area where the heat reflector 320 acts on the growth interface has a stronger heat preservation effect. The area that receives the reflected heat has a certain heat preservation effect, and its radial temperature decreases more slowly than the area that does not receive the reflection, thereby adjusting the radial temperature gradient at the growth interface of the crystal to be grown 210. The drive component 310 can selectively move different heat reflectors 320 above the crystal to be grown 210 to achieve real-time adjustment of the radial temperature gradient at the growth interface of the crystal to be grown 210, thereby meeting the radial temperature gradient required for different crystal growth processes, so as to effectively reduce crystal defects, improve substrate yield, and obtain the required crystal morphology.

[0069] It should be noted that in this embodiment, heat reflection refers to the ability to block heat and reflect some of it; it can also be manifested as blocking heat flow, causing the heat flow to be reflected back under the blocking effect; that is, the heat flow above the crystal to be grown 210 can be reflected towards the crystal to be grown 210 under the blocking effect of the heat reflector 320. It can be understood that the growth interface area of ​​the crystal to be grown 210 affected by the reflected heat flow is subjected to a certain heat preservation effect and the temperature is relatively high; the growth interface temperature of the crystal to be grown 210 that is not affected by the reflected heat flow is relatively low; when the growth interface of the crystal to be grown 210 affected by the reflected heat flow and the growth interface of the crystal to be grown 210 that is not affected by the reflected heat flow are distributed in the radial direction of the crystal to be grown 210, a radial temperature gradient is generated.

[0070] Please see Figure 1 and Figure 2 The plurality of heat reflectors 320 include a first heat reflector 321 and a second heat reflector 322.

[0071] Please see Figure 3 In some embodiments, the first heat reflector 321 is a disc-shaped heat reflector. The disc-shaped heat reflector can completely block the heat flow from the direction of the crystal to be grown 210, and cause the heat flow to be reflected back towards the growth interface of the crystal to be grown 210 under the blocking effect, thus completing the reflection of heat. Heat located above the crystal to be grown 210 is reflected back to the crystal to be grown 210 and acts on the growth interface of the crystal to be grown 210 under the action of the first heat reflector 321. It is understood that the area of ​​the crystal to be grown 210 affected by the reflected heat flow corresponds to the area of ​​the first heat reflector 321. When the area of ​​the first heat reflector 321 is greater than or equal to that of the crystal to be grown 210, the reflected heat flow can completely act on the middle and edges of the growth interface of the crystal to be grown 210.

[0072] Please see Figure 1 and Figure 4 The second heat reflector 322 is a ring-shaped heat reflector. When it is necessary to keep the edge of the growth interface of the crystal to be grown 210 warm, the second heat reflector 322 is moved above the crystal to be grown 210 by the drive component 310.

[0073] In this embodiment, the second heat reflector 322 includes a non-heat reflective region 3221 at the center and a heat reflective region 3222 surrounding the non-heat reflective region 3221.

[0074] Understandably, when the second heat reflector 322 moves above the crystal to be grown 210, some heat flow can pass through the non-heat reflective area 3221 in the center, while some heat flow is deflected back towards the growth interface of the crystal to be grown 210 under the blocking effect of the heat reflective area 3222; the heat above the crystal to be grown 210 is partially reflected to the edge of the growth interface of the crystal to be grown 210 under the action of the second heat reflector 322, thereby achieving heat preservation of the edge of the crystal to be grown 210.

[0075] It should be noted that the areas of the heat reflection area 3222 and the non-heat reflection area 3221 can be adjusted according to actual working needs.

[0076] Specifically, the radius corresponding to the non-heat-reflecting region 3221 is r The radius corresponding to the heat reflection region 3222 is R ,in, .

[0077] In some embodiments, the second heat reflector 322 may be configured as a plurality of second heat reflectors 322, and the area ratio of the heat reflective area 3222 and the non-heat reflective area 3221 in the plurality of second heat reflectors 322 may be different.

[0078] Please see Figure 5 Furthermore, in this embodiment, the plurality of heat reflectors 320 also include a third heat reflector 323. Similar to the first heat reflector 321, the third heat reflector 323 is also a disc-shaped heat reflector. The difference is that the radius of the third heat reflector 323 is smaller than that of the first heat reflector 321, so as to construct different thermal environments on the growth interface of the crystal to be grown 210.

[0079] In this embodiment, the area of ​​the first heat reflector 321 is approximately the same as the area of ​​the crystal to be grown 210, and the area of ​​the third heat reflector 323 is 0.25-0.3 times the area of ​​the crystal to be grown 210. Therefore, when the growth interface of the crystal to be grown 210 needs to be fully acted upon by the reflected heat flow to reduce the growth rate of the crystal, the first heat reflector 321 is moved above the crystal to be grown 210 by the driving component 310. When it is necessary to keep the middle part of the crystal to be grown 210 warm to reduce the convexity of the middle part of the crystal to be grown 210, the third heat reflector 323 is moved above the crystal to be grown 210 by the driving component 310.

[0080] In this embodiment, the convexity of the crystal to be grown 210 refers to the degree of curvature of the crystal growth interface relative to the ideal plane, that is, the degree to which the crystal growth interface protrudes towards the silicon carbide powder 220.

[0081] In practical applications, the arrangement of the heat reflector 320 affects both the growth quality of the crystal and the formation of its morphology. Specifically, regarding the formation of the crystal morphology:

[0082] When the first heat reflector 321 is moved above the crystal to be grown 210, the heat above the crystal to be grown 210 is reflected by the first heat reflector 321 and acts on the growth interface of the crystal to be grown 210, thus keeping the middle and edge of the growth interface of the crystal to be grown 210 warm at the same time. At this time, the vapor deposition rate of the middle and edge of the growth interface decreases at the same time, thereby reducing the growth rate of the crystal.

[0083] When the second heat reflector 322 is moved above the crystal to be grown 210, the heat above the crystal to be grown 210 is partially reflected to the edge of the growth interface of the crystal to be grown 210 under the action of the second heat reflector 322. The reflected heat flow can act on the edge of the growth interface of the crystal to be grown 210 to keep the edge of the growth interface of the crystal to be grown 210 warm. At this time, the vapor deposition rate at the edge of the growth interface decreases, thereby increasing the convexity of the middle part of the growth interface of the crystal to be grown 210.

[0084] When the third heat reflector 323 is moved above the crystal to be grown 210, the heat above the crystal to be grown 210 is partially reflected to the middle of the growth interface of the crystal to be grown 210 under the action of the second heat reflector 322. The reflected heat flow can act on the middle of the growth interface of the crystal to be grown 210 to keep the middle of the growth interface of the crystal to be grown 210 warm. At this time, the vapor deposition rate in the middle of the growth interface decreases, thereby reducing the convexity of the middle of the growth interface of the crystal to be grown 210.

[0085] Please continue reading. Figure 1 and Figure 2 In order to further control the influence of the reverse heat flow on the temperature gradient of the growth interface of the crystal to be grown 210, in this embodiment, the radial temperature gradient adjustment device 300 also includes a first fixed platform 330 and a second fixed platform 340 for fixing the drive component 310 and driving the drive component 310 to move up and down in the axial direction.

[0086] It should be noted that the first fixed platform 330 and the second fixed platform 340 can move up and down under the action of an external drive mechanism (not shown in the figure), thereby driving the drive component 310 and the multiple heat reflectors 320 connected to the drive component 310 to move up and down.

[0087] It is understandable that the lifting and lowering movement of the heat reflector 320 can change the distance between the heat reflector 320 and the crystal to be grown 210. As the distance between the heat reflector 320 and the crystal to be grown 210 decreases, the heat reflection effect of the heat reflector 320 on the crystal to be grown 210 is enhanced, thereby increasing the influence on the crystal morphology. As the distance between the heat reflector 320 and the crystal to be grown 210 increases, the heat reflection effect of the heat reflector 320 on the crystal to be grown 210 is weakened, thereby decreasing the influence on the crystal morphology.

[0088] In order to monitor the temperature of each part of the crystal to be grown 210 in real time, in this embodiment, a plurality of temperature detection devices 400 are provided on the second fixed platform 340. The plurality of temperature detection devices 400 can obtain temperature data at the corresponding positions on the growth interface of the crystal to be grown 210.

[0089] Specifically, two temperature sensing elements 400 are set and arranged radially along the crystal to be grown 210, so as to obtain radial temperature gradient data of the crystal to be grown 210.

[0090] For example, the temperature detection element 400 is an infrared thermometer. Correspondingly, the second fixed platform 340, the top wall 120, the first heat reflector 321, the second heat reflector 322, and the third heat reflector 323 are all provided with monitoring holes 500, and the temperature detection element 400 detects the radial temperature gradient of the crystal 210 to be grown through the monitoring holes 500.

[0091] In actual operation, the operator can obtain radial temperature gradient data of the crystal to be grown 210 through multiple temperature detection devices 400, and then select the corresponding heat reflector 320 through the drive component 310 to move it above the crystal to be grown 210 and reflect heat to the crystal to be grown 210.

[0092] Please continue reading. Figure 1 In this embodiment, the driving component 310 includes a first driving unit 311, a second driving unit 312, and a third driving unit 313 for driving the first heat reflector 321, the second heat reflector 322, and the third heat reflector 323, respectively.

[0093] Specifically, the first drive unit 311 includes a first drive motor 3111, a first drive rod 3112 connected to the first drive motor 3111, and a first rotating member 3113 connected to the first drive rod 3112; the second drive unit 312 includes a second drive motor 3121, a second drive rod 3122 connected to the second drive motor 3121, and a second rotating member 3123 connected to the second drive rod 3122; the third drive unit 313 includes a third drive motor 3131, a third drive rod 3132 connected to the third drive motor 3131, and a third rotating member 3133 connected to the third drive rod 3132.

[0094] In this embodiment, the connections between the first drive motor 3111 and the first drive rod 3112, the second drive motor 3121 and the second drive rod 3122, and the third drive motor 3131 and the third drive rod 3132 are conventional, such as through couplings. The connections between the first drive rod 3112 and the first rotating member 3113, the second drive rod 3122 and the second rotating member 3123, and the third drive rod 3132 and the third rotating member 3133 are gear and toothed sleeve meshing connections. Specifically, a toothed sleeve is provided on the outer side of the first rotating member 3113, and a gear is provided at one end of the first drive rod 3112 near the first rotating member 3113. The gear meshes with the toothed sleeve, thereby enabling the first drive rod 3112 to drive the first rotating member 3113 to rotate. The connection relationships between the second drive rod 3122 and the second rotating member 3123, and between the third drive rod 3132 and the third rotating member 3133, are similar to the connection relationships between the first drive rod 3112 and the first rotating member 3113, and will not be described again here.

[0095] Furthermore, the first heat reflector 321, the second heat reflector 322, and the third heat reflector 323 are respectively connected to the first rotating member 3113, the second rotating member 3123, and the third rotating member 3133 via transmission.

[0096] It should be noted that, in order to ensure that the first heat reflector 321, the second heat reflector 322, and the third heat reflector 323 can be aligned and act on the crystal 210 to be grown, the first heat reflector 321, the second heat reflector 322, and the third heat reflector 323 are connected to the first rotating component 3113, the second rotating component 3123, and the third rotating component 3133 via connecting rods of different lengths. The length of the connecting rods can be adaptively adjusted according to actual working needs, with the aim of ensuring that the first heat reflector 321, the second heat reflector 322, and the third heat reflector 323 can be aligned and act on the crystal 210 to be grown, and no limitation is made here.

[0097] In this embodiment, the first rotating member 3113, the second rotating member 3123 and the third rotating member 3133 are coaxially arranged and are sequentially sleeved and connected from the inside to the outside.

[0098] In several other embodiments, the first heat reflector 321, the second heat reflector 322, and the third heat reflector 323 have multiple driving methods. For example, the first heat reflector 321, the second heat reflector 322, and the third heat reflector 323 are mounted on the same rotating shaft via a connecting rod. The difference lies in that the first heat reflector 321, the second heat reflector 322, and the third heat reflector 323 have different heights and angles. When the rotating shaft rotates to the first angle, the first heat reflector 321 is positioned above the crystal 210 to be grown; when the rotating shaft rotates to the second angle, the second heat reflector 322 is positioned above the crystal 210 to be grown; and when the rotating shaft rotates to the third angle, the third heat reflector 323 is positioned above the crystal 210 to be grown. Alternatively, for example, the first heat reflector 321, the second heat reflector 322, and the third heat reflector 323... The three heat reflectors 323 are controlled by three independent rotating shafts. When the first rotating shaft rotates, the first heat reflector 321 is positioned above the crystal to be grown 210. When the second rotating shaft rotates, the second heat reflector 322 is positioned above the crystal to be grown 210. When the third rotating shaft rotates, the third heat reflector 323 is positioned above the crystal to be grown 210. When the first heat reflector 321, the second heat reflector 322, and the third heat reflector 323 are controlled by independent rotating shafts, they can be flexibly arranged in the crucible 200 in conjunction with an external lifting mechanism. For example, the arrangement order of the first heat reflector 321, the second heat reflector 322, and the third heat reflector 323 in the height direction can be interchanged.

[0099] Furthermore, in some embodiments, to meet the complex requirements of radial temperature gradient adjustment at the growth interface of the crystal to be grown 210, multiple sets of radial temperature gradient adjustment devices 300 can be configured. For example, two sets of radial temperature gradient adjustment devices 300 are configured, and correspondingly, the two sets of radial temperature gradient adjustment devices 300 include two sets of multiple heat reflectors 320 and a drive assembly 310; the two sets of radial temperature gradient adjustment devices 300 can be used in conjunction so that the multiple heat reflectors 320 in the two sets of radial temperature gradient adjustment devices 300 can be combined with each other to further refine the control of the radial temperature gradient at the growth interface of the crystal to be grown 210.

[0100] Please see Figures 6 to 11 , Figures 6 to 11 The arrow located above the crystal 210 to be grown shows the path of heat flow being deflected by the heat reflector 320.

[0101] The specific working process of the radial temperature gradient adjustable crystal growth apparatus provided in this embodiment is as follows:

[0102] Please see Figure 6 When it is necessary to reduce the crystal growth rate, the first heat reflector 321 is moved above the crystal 210 to be grown via the drive component 310, such as... Figure 6 As shown by the middle arrow, heat is simultaneously reflected to the middle and edge of the crystal growth interface, and the middle and edge of the crystal growth interface are simultaneously kept warm, thereby reducing the crystal growth rate.

[0103] Please see Figure 7 When it is necessary to reduce the convexity of the middle part of the crystal to be grown 210, the third heat reflector 323 is moved above the crystal to be grown 210 by the drive assembly 310; such as Figure 7 As shown by the middle arrow, at this time, some of the heat is reflected to the middle of the crystal growth interface, which keeps the middle of the crystal growth interface warm and reduces the convexity of the middle of the crystal. At this time, the crystal morphology shows that the middle of the crystal has a small convexity.

[0104] When the convexity of the middle part of the crystal is small, the temperature of the middle part of the crystal can be further increased by means of thermal field control, so that the growth rate of the crystal edge is greater than that of the middle part of the crystal, and thus the crystal morphology presents a central depression.

[0105] Please see Figure 8 Furthermore, to facilitate the creation of a centrally concave crystal morphology through methods such as thermal field control, in this embodiment, the first heat reflector 321 and the third heat reflector 323 are simultaneously moved above the crystal 210 to be grown by the driving component 310; Figure 8 As shown by the middle arrow, at this time, part of the heat is reflected to the middle of the crystal 210 to be grown under the action of the third heat reflector 323, and another part of the heat is reflected to the edge of the crystal growth interface under the action of the first heat reflector 321. Due to the difference in the action distance, the heat reflected to the edge of the crystal growth interface should be lower than the heat reflected to the middle of the crystal growth interface. At this time, compared with the case where only the third heat reflector 323 is set, the crystal growth speed in the middle of the crystal growth interface is further reduced and the convexity is smaller, which makes it easier to make the crystal morphology present as a central depression through methods such as thermal field control.

[0106] Please see Figure 9 When it is necessary to increase the convexity of the middle part of the crystal to be grown 210 so that the crystal morphology presents a central convex shape, the second heat reflector 322 is moved above the crystal to be grown 210 by the drive assembly 310; such as Figure 9As shown by the middle arrow, at this time, some of the heat is reflected to the edge of the crystal growth interface. The reflected heat flow can create a specific thermal environment on the crystal growth interface that is "cooler in the middle and hotter at the edge", thus making the crystal morphology appear as a central bulge.

[0107] Please see Figure 10 To further adjust the crystal morphology, when a slightly convex central shape is desired, the first heat reflector 321 and the second heat reflector 322 are simultaneously moved above the crystal 210 to be grown via the drive assembly 310; for example... Figure 10 As shown by the middle arrow, at this time, part of the heat is reflected to the edge of the crystal to be grown 210 under the action of the second heat reflector 322, and another part of the heat is reflected to the middle of the crystal growth interface under the action of the first heat reflector 321. Compared with the case where only the second heat reflector 322 is provided, due to the reduction of the radial temperature gradient, the crystal growth rate at the edge of the crystal growth interface is relatively reduced, so that the crystal morphology presents a slightly convex shape in the middle.

[0108] It should be noted that, in this embodiment, "a slightly convex central crystal morphology" means that the convexity of the central part of the crystal is lower than that of the central part when the crystal morphology is convex. Figure 10 The dashed line at the crystal growth interface shows the convex shape of the middle part of the crystal when the crystal morphology is convex in the middle.

[0109] Please see Figure 11 ,and Figure 9 and Figure 10 The working process shown is similar, except that the non-heat-reflecting region 3221 in the second heat reflector 322 has a larger area, so that a specific thermal environment is needed to be formed at the growth interface of the crystal to be grown 210, which "only heats the part near the edge".

[0110] The radial temperature gradient adjustable crystal growth apparatus provided in this embodiment can selectively move different heat reflectors 320 above the crystal to be grown 210 through the drive component 310 and the temperature detection component 400. It can also adjust the radial temperature gradient of the crystal to be grown 210 in real time according to the actual radial temperature value of the growth interface of the crystal to be grown 210, thereby meeting the radial temperature gradient required for different crystal growth processes. This effectively reduces crystal defects, improves substrate yield, and obtains the desired crystal morphology.

[0111] Example 2:

[0112] In the physical vapor transport method for silicon carbide (SVC), facet 600 with a certain offset angle (usually 1°-8°) needs to be grown first to provide a stable step flow for crystal growth, thus promoting the growth of high-quality SVC ingots. However, due to different growth kinetics, facet 600 is more prone to doping, resulting in different physicochemical properties compared to other crystal regions, which can affect the performance of some SVC power devices. Therefore, the growth location and size of facet 600 need to be limited to increase the usable area of ​​the SVC substrate.

[0113] Please see Figure 12 , Figure 12 The dashed line shows the facet 600 region on the crystal 210 to be grown.

[0114] Please see Figure 13 This embodiment also provides a radial temperature gradient adjustable crystal growth apparatus, whose overall structure, working principle and technical effect are basically the same as those of Embodiment 1. The difference is that the crucible 200 includes a crucible cover 230 for setting the crystal 210 to be grown. A thinning portion 240 is provided on the side end face of the crucible cover 230 away from the crystal 210 to be grown. The position of the thinning portion 240 corresponds to the position of the small face 600 of the crystal 210 to be grown, so as to increase the heat dissipation at the small face 600 of the crystal 210 to be grown.

[0115] In this embodiment, a thinning portion 240 is formed on the crucible cover 230 corresponding to the facet 600. Due to the presence of the thinning portion 240, the thickness of the crucible cover 230 corresponding to the facet 600 is less than that of other positions, thereby enhancing the heat dissipation at the facet 600. This makes the temperature at the facet 600 slightly lower than that of other areas, thereby promoting the formation and growth of the facet 600 and making the growth rate at the facet 600 slightly greater than that of other areas of the crystal.

[0116] Meanwhile, a step portion 250 is formed at the connection between the thinned portion 240 and the crucible 200. Compared with the thinned portion 240, the temperature near the step portion 250 is higher, which makes the growth rate of the crystal located in the step portion 250 slightly lower than the growth rate of the facet 600, thereby restricting the facet 600 to a position near the step portion 250.

[0117] Specifically, the cutting method for the thinned portion 240 is to cut at an angle along the surface of the crucible lid 230, so that the angle between the surface of the thinned portion 240 and the horizontal is 4°-20°.

[0118] The radial temperature gradient adjustable crystal growth apparatus provided in this embodiment, based on the first embodiment, promotes the formation and growth of facets 600 by providing a thinning section 240, and limits and divides the growth position of facets 600 by combining a step section 250, so as to effectively control the size of facets 600 of silicon carbide crystal and increase the usable area of ​​silicon carbide substrate.

[0119] Example 3:

[0120] Please see Figure 14 This embodiment provides a radially temperature gradient adjustable crystal growth method based on the radially temperature gradient adjustable crystal growth apparatus provided in Embodiments 1 and 2, including the following steps:

[0121] S1. Arrange the crystal to be grown 210 and silicon carbide powder 220 in the crucible 200, and place the crucible 200 in the heating furnace 100. Set the radial temperature gradient adjustment device 300 on the heating furnace 100.

[0122] In this embodiment, the crucible 200 is used to provide the growth environment required for crystal growth. The crucible 200 is placed in the heating furnace 100, which is used to provide the thermal environment required for crystal growth. The crucible 200 needs to be heated and cooled within the heating furnace 100. The heating and cooling methods for the crucible 200 are similar to those in the prior art and are not limited here.

[0123] S2. Start the heating furnace 100 and heat the crucible 200 to allow the crystal to be grown 210 to enter the crystal growth stage; during the crystal growth stage, the temperature of the middle and / or edge of the growth interface of the crystal to be grown 210 is adjusted in real time by the radial temperature gradient adjustment device 300 to adjust the crystal growth rate or obtain different crystal morphologies.

[0124] In this embodiment, the radial temperature gradient at the growth interface of the crystal to be grown 210 is adjusted in real time by the radial temperature gradient adjustment device 300 to adjust the crystal growth rate.

[0125] The heat reflector 320 is moved to the top of the growth interface of the crystal to be grown 210, and the heat above the crystal to be grown 210 is reflected to the middle and edge of the growth interface of the crystal to be grown 210 at the same time, so as to keep the middle and edge of the growth interface of the crystal to be grown 210 warm at the same time, thereby reducing the growth rate of the crystal.

[0126] In this embodiment, the radial temperature gradient at the growth interface of the crystal to be grown 210 is adjusted in real time by the radial temperature gradient adjustment device 300 to obtain different crystal morphologies.

[0127] The heat reflector 320 is moved to the top of the growth interface of the crystal to be grown 210, and the heat above the crystal to be grown 210 is reflected to the middle of the growth interface of the crystal to be grown 210, so as to keep the middle of the growth interface of the crystal to be grown 210 warm and reduce the convexity of the middle of the crystal; or the heat reflector 320 is moved to the top of the growth interface of the crystal to be grown 210, and the heat above the crystal to be grown 210 is reflected to the edge of the growth interface of the crystal to be grown 210, so as to keep the edge of the growth interface of the crystal to be grown 210 warm and increase the convexity of the middle of the crystal.

[0128] The radial temperature gradient adjustable crystal growth method provided in this embodiment, by setting a radial temperature gradient adjustment device 300 in the heating furnace 100, can adjust the radial temperature gradient at the growth interface of the crystal to be grown 210 in real time during the silicon carbide crystal growth process. In this way, the radial temperature gradient at the growth interface of the crystal to be grown 210 can be dynamically adjusted according to different stages of the crystal growth process, which can effectively reduce crystal defects, improve substrate yield, and obtain the desired crystal morphology.

[0129] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A radial temperature gradient adjustable crystal growth apparatus, characterized by, The application relates to a heating furnace (100) comprising opposite side walls (110) and a top wall (120), a heating space (130) being defined between the side walls (110) and the top wall (120); a crucible (200) arranged in the heating space (130), the crucible (200) containing a to-be-grown crystal (210) and silicon carbide powder (220) respectively; a radial temperature gradient adjusting device (300) arranged on the top wall (120), the radial temperature gradient adjusting device (300) comprising a driving assembly (310) and a plurality of heat reflecting elements (320) connected with the driving assembly (310); the plurality of heat reflecting elements (320) are selectively moved above the to-be-grown crystal (210) under the action of the driving assembly (310) to reflect at least part of heat above the to-be-grown crystal (210) to the to-be-grown crystal (210), so as to adjust the radial temperature gradient at the growth interface of the to-be-grown crystal (210); the plurality of heat reflecting elements (320) comprise a first heat reflecting element (321) and a second heat reflecting element (322); wherein the first heat reflecting element (321) is a disc-shaped heat reflecting element, and the second heat reflecting element (322) is a ring-shaped heat reflecting element; the plurality of heat reflecting elements (320) further comprise a third heat reflecting element (323); the third heat reflecting element (323) is a disc-shaped heat reflecting element, and the radius of the third heat reflecting element (323) is smaller than that of the first heat reflecting element (321); the second heat reflecting element (322) comprises a non-heat reflecting area (3221) and a heat reflecting area (3222) surrounding the non-heat reflecting area (3221); the radial temperature gradient adjusting device (300) further comprises a first fixing platform (330) and a second fixing platform (340) for fixing the driving assembly (310) and enabling the driving assembly (310) to ascend and descend in the axial direction; wherein the second fixing platform (340) is provided with a plurality of temperature detecting elements (400); the plurality of temperature detecting elements (400) are used for detecting the radial temperature gradient at the growth interface of the to-be-grown crystal (210); the second fixing platform (340), the top wall (120), the first heat reflecting element (321), the second heat reflecting element (322) and the third heat reflecting element (323) are all provided with monitoring holes (500), and the temperature detecting elements (400) detect the radial temperature gradient at the growth interface of the to-be-grown crystal (210) through the monitoring holes (500); the driving assembly (310) comprises a first driving unit (311), a second driving unit (312) and a third driving unit (313). ​ ​ ​ ​ ​ ​ ​ 2. The radial temperature gradient adjustable crystal growing apparatus according to claim 1, wherein ​ The non-heat reflecting region (3221) corresponds to a radius of r The heat reflecting region (3222) corresponds to a radius of R wherein .

3. The radial temperature gradient adjustable crystal growing apparatus according to claim 1, wherein ​ ​ ​ 4. The radial temperature gradient adjustable crystal growing apparatus according to claim 3, wherein ​ The first driving unit (311) comprises a first driving motor (3111), a first driving rod (3112) connected with the first driving motor (3111), and a first rotating part (3113) connected with the first driving rod (3112); The second driving unit (312) comprises a second driving motor (3121), a second driving rod (3122) connected with the second driving motor (3121), and a second rotating part (3123) connected with the second driving rod (3122); The third driving unit (313) comprises a third driving motor (3131), a third driving rod (3132) connected with the third driving motor (3131), and a third rotating part (3133) connected with the third driving rod (3132); The first heat reflecting part (321), the second heat reflecting part (322) and the third heat reflecting part (323) are respectively in transmission connection with the first rotating part (3113), the second rotating part (3123) and the third rotating part (3133).

5. The radial temperature gradient adjustable crystal growing apparatus according to claim 4, wherein The first rotating part (3113), the second rotating part (3123) and the third rotating part (3133) are coaxially arranged and connected in sequence from inside to outside.

6. The radial temperature gradient adjustable crystal growing apparatus according to claim 1, wherein, The crucible (200) comprises a crucible cover (230) for arranging the to-be-grown crystal (210), and a thinning portion (240) is formed on the side end face of the crucible cover (230) away from the to-be-grown crystal (210); The thinning portion (240) is arranged at a position corresponding to the facet position of the to-be-grown crystal (210) to increase the heat dissipation at the facet of the to-be-grown crystal (210).

7. A radial temperature gradient adjustable crystal growth method, characterized by, The radial temperature gradient adjustable crystal growth device according to any one of claims 1-6 comprises: The to-be-grown crystal (210) and silicon carbide powder (220) are arranged in the crucible (200), and the crucible (200) is placed in the heating furnace (100), and the radial temperature gradient adjusting device (300) is arranged on the heating furnace (100); The heating furnace (100) is started to heat the crucible (200), so that the to-be-grown crystal (210) enters the crystal growth stage; in the crystal growth stage, the temperature of the middle and / or edge of the growth interface of the to-be-grown crystal (210) is adjusted in real time by the radial temperature gradient adjusting device (300), so as to adjust the growth speed of the crystal or obtain different crystal morphologies.

8. The radial temperature gradient adjustable crystal growth method as claimed in claim 7, wherein The method for adjusting the growth speed of the crystal is: The heat reflecting part (320) is driven to move above the growth interface of the to-be-grown crystal (210), and the heat above the to-be-grown crystal (210) is simultaneously reflected to the middle and edge of the growth interface of the to-be-grown crystal (210), so as to simultaneously keep warm the middle and edge of the growth interface of the to-be-grown crystal (210), so as to reduce the growth speed of the crystal; The method for obtaining different crystal morphologies is: The heat reflecting member (320) is driven to move above the growth interface of the to-be-grown crystal (210), and reflects the heat above the to-be-grown crystal (210) to the middle part of the growth interface of the to-be-grown crystal (210), so as to keep the middle part of the growth interface of the to-be-grown crystal (210) warm, thereby reducing the convexity of the middle part of the crystal. The heat reflecting member (320) is driven to move above the growth interface of the to-be-grown crystal (210), and reflects the heat above the to-be-grown crystal (210) to the edge of the growth interface of the to-be-grown crystal (210), so as to keep the edge of the growth interface of the to-be-grown crystal (210) warm, thereby increasing the convexity of the middle part of the crystal.

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