Crystal structure and preparation method and preparation device thereof

Abstract

The embodiment of the invention provides a crystal structure and a preparation method and a preparation device thereof, and the preparation device of the crystal structure comprises a furnace body; the furnace body comprises a mounting cavity with an opening; a furnace cover; the furnace cover is arranged at the opening of the mounting cavity; a furnace core; the furnace core is arranged in the mounting cavity, and an annular cavity is formed by the furnace core and the side wall of the mounting cavity; a cooling device; the cooling device is arranged in the mounting cavity and is positioned between the furnace cover and the furnace core; a rotating shaft; the rotating shaft penetrates through the furnace cover and is fixedly connected with the cooling device; and the rotating shaft can drive the cooling device to move relative to the annular cavity.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor preparation technology, and in particular to a crystal structure and a preparation method and a preparation device thereof. Background Art

[0002] Compared with silicon-based semiconductors, the third-generation semiconductors represented by silicon carbide (SiC) have the characteristics of wide band gap, high saturated electron mobility, high breakdown electric field strength, and high thermal conductivity. They have superior performance such as high frequency, high temperature resistance, chemical corrosion resistance, high efficiency, strong radiation resistance, and high voltage resistance. They have the characteristics of wide band gap, high critical electric field, high thermal conductivity, and high current saturation drift velocity. They have broad application prospects in semiconductor lighting, new generation mobile communications, smart grids, high-speed rail transit, new energy vehicles, and consumer electronics. They are key new materials supporting the development of information, energy, transportation, national defense and other industries.

[0003] At present, the preparation methods of silicon carbide crystals include high temperature chemical vapor deposition (HTCVD), liquid phase epitaxy (Liquid Phase Epitaxy) and physical vapor transport (PVT). The commonly used preparation method is the PVT method. However, in the process of preparing silicon carbide crystals or other crystals by the PVT method, there are still many problems that need to be solved. Summary of the invention

[0004] In order to solve one or more of the above problems, the embodiments of the present disclosure propose a crystal structure and a preparation method and a preparation device thereof. On the one hand, the preparation device of a crystal structure provided by the embodiments of the present disclosure includes: a furnace body; the furnace body includes an installation cavity with an opening; a furnace cover; the furnace cover is arranged at the opening of the installation cavity; a furnace core; the furnace core is arranged in the installation cavity and forms an annular cavity with the side wall of the installation cavity; a cooling device; the cooling device is arranged in the installation cavity and is located between the furnace cover and the furnace core; a rotating shaft; the rotating shaft passes through the furnace cover and is fixedly connected to the cooling device; wherein the rotating shaft can drive the cooling device to move relative to the annular cavity.

[0005] In some embodiments, the preparation device further comprises: an annular reaction body, comprising a side wall and a bottom surface; the annular reaction body is placed in the annular cavity, and the opening of the annular reaction body is arranged toward the cooling device;

[0006] The annular reaction body comprises a first crucible body and a second crucible body stacked in a first direction; the first crucible body and the second crucible body can be separated at a connection point between the first direction and the side wall extension direction of the installation cavity.

[0007] In some embodiments, the first crucible body and the second crucible body are connected by bolts, rivets or interlocking.

[0008] In some embodiments, at the inner side wall of the annular reaction body, the connection between the first crucible body and the second crucible body is kept smooth; or, graphite paper is arranged between the connection between the first crucible body and the second crucible body.

[0009] In some embodiments, the preparation device further comprises: a substrate, fixedly disposed on a side of the cooling device away from the rotating shaft; a seed layer, fixedly disposed on a side of the substrate away from the cooling device;

[0010] Wherein, the surface of the seed crystal layer away from the substrate covers the opening of the annular reaction body.

[0011] In some embodiments, the width of the seed layer in the second direction is greater than the width of the opening of the annular reaction body in the second direction; and the second direction is perpendicular to the extension direction of the side wall of the annular reaction body.

[0012] In some embodiments, the rotating shaft drives the cooling device, the substrate and the seed layer to rise or fall in the first direction; and / or,

[0013] The rotating shaft drives the cooling device, the substrate and the seed crystal layer to rotate in a clockwise direction or a counterclockwise direction on a first plane; the first plane is perpendicular to the first direction.

[0014] In some embodiments, the preparation device further includes: a heat insulation device, which is disposed in the installation cavity and covers the side wall of the installation cavity, the bottom surface of the installation cavity, the surface of the furnace core, and the surface of one side of the furnace cover close to the installation cavity; and

[0015] The heating device is arranged between the annular reaction body and the heat insulation device.

[0016] On the other hand, an embodiment of the present disclosure provides a method for preparing a crystal structure, and the crystal structure is prepared using the preparation device described in the above embodiment of the present disclosure; wherein, during the process of preparing the crystal structure using the preparation device, the cooling device is driven to move relative to the annular cavity by controlling the rotating shaft.

[0017] In some embodiments, the method further comprises: placing an annular reaction body in the annular cavity, and arranging the opening of the annular reaction body toward the cooling device;

[0018] The annular reaction body comprises a first crucible body and a second crucible body stacked in a first direction; the first crucible body and the second crucible body can be separated at a connection point between the first direction and the side wall extension direction of the installation cavity.

[0019] In some embodiments, the method also includes: fixing the substrate on a side of the cooling device away from the rotating shaft; fixing the seed crystal layer on a side of the substrate away from the cooling device, and making the surface of the seed crystal layer away from the substrate cover the opening of the annular reaction body; setting the heat insulation device in the installation cavity, and making the heat insulation device cover the side wall of the installation cavity, the bottom surface of the installation cavity, the surface of the furnace core and the surface of the furnace cover on one side close to the installation cavity; and setting the heating device between the annular reaction body and the heat insulation device.

[0020] In some embodiments, the method also includes: controlling the rotating shaft so that the rotating shaft drives the cooling device, the substrate and the seed crystal layer to rise or fall in the first direction; and / or so that the rotating shaft drives the cooling device, the substrate and the seed crystal layer to rotate clockwise or counterclockwise on a first plane; the first plane is perpendicular to the first direction.

[0021] In some embodiments, the method further includes: controlling the heating device to increase the temperature of the side wall and the bottom surface of the annular reaction body to control the temperature inside the annular reaction body.

[0022] In some embodiments, the method further includes: controlling the heating device and / or the cooling device so that the temperature difference between the temperature of the side of the annular reaction body close to the bottom surface of the annular reaction body and the temperature of the cooling device is within the range of 50°C to 200°C.

[0023] In some embodiments, the method further includes: after completing the preparation of the crystal structure, disassembling or breaking the first crucible body to take out the crystal structure.

[0024] On the other hand, an embodiment of the present disclosure provides a crystal structure, which is prepared by the crystal structure preparation method described in the above embodiment of the present disclosure, and the overall shape of the crystal structure is ring-shaped.

[0025] In some embodiments, the crystal structure includes silicon carbide, aluminum nitride, tantalum carbide, boron carbide, zinc selenide.

[0026] The embodiments of the present disclosure provide a crystal structure and a preparation method and a preparation device thereof. Among them, the preparation device of the crystal structure includes a furnace body; the furnace body includes an installation cavity with an opening; a furnace cover; the furnace cover is arranged at the opening of the installation cavity; a furnace core; the furnace core is arranged in the installation cavity and forms an annular cavity with the side wall of the installation cavity; a cooling device; the cooling device is arranged in the installation cavity and is located between the furnace cover and the furnace core; a rotating shaft; the rotating shaft passes through the furnace cover and is fixedly connected to the cooling device; wherein the rotating shaft can drive the cooling device to move relative to the annular cavity. In the embodiments of the present disclosure, by arranging a furnace core in the installation cavity, an annular cavity is formed between the side wall of the installation cavity and the furnace core, so that the crystal structure formed in the annular cavity can be annular as a whole; in addition, by driving the cooling device to move relative to the annular cavity through the rotating shaft, the growth environment in the annular cavity can be changed, so that the quality of the crystal structure can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a device for preparing a crystal structure provided in one embodiment of the present disclosure;

[0028] Figure 2 A schematic diagram of the overall structure of a SiC focusing ring provided in one embodiment of the present disclosure;

[0029] Figure 3 A schematic diagram of a device for preparing a crystal structure provided in another embodiment of the present disclosure;

[0030] Figure 4 A schematic diagram of a device for preparing a crystal structure provided in yet another embodiment of the present disclosure;

[0031] Figure 5 for Figure 4 A partial cross-sectional enlarged schematic diagram of the preparation device shown in the XZ plane;

[0032] Figure 6 A schematic diagram of a structure in which the bottom surface of a ring-shaped reaction body is in a disc shape is provided for another embodiment of the present disclosure;

[0033] Figure 7 A schematic diagram of the structure of a heating device surrounding an annular reaction body provided in one embodiment of the present disclosure.

[0034] In the above drawings (which are not necessarily drawn to scale), similar reference numerals may describe similar components in different views. Similar reference numerals with different letter suffixes may represent different examples of similar components. The accompanying drawings generally illustrate various embodiments discussed herein by way of example and not limitation. DETAILED DESCRIPTION

[0035] The following will be combined with the embodiments of the present disclosure and the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0036] In the following description, a large number of specific details are given to provide a more thorough understanding of the present disclosure. However, it is obvious to those skilled in the art that the present disclosure can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present disclosure, some technical features known in the art are not described; that is, all features of actual embodiments are not described here, and well-known functions and structures are not described in detail.

[0037] In the drawings, the sizes of layers, regions, elements and their relative sizes may be exaggerated for clarity. Like reference numerals denote like elements throughout.

[0038] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present disclosure, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. And when the second element, component, region, layer or part is discussed, it does not indicate that the present disclosure necessarily has the first element, component, region, layer or part.

[0039] Spatially relative terms such as "under", "beneath", "below", "under", "above", "above", etc., may be used here for convenience of description to describe the relationship between an element or feature shown in the figure and other elements or features. It should be understood that in addition to the orientation shown in the figure, the spatial relationship terms are intended to also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is turned over, then the elements or features described as "under other elements" or "under it" or "under it" will be oriented as "on" other elements or features. Therefore, the exemplary terms "under" and "under" may include both upper and lower orientations. The device can be oriented otherwise (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.

[0040] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be a limitation of the present disclosure. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0041] In order to thoroughly understand the present disclosure, detailed steps and detailed structures will be presented in the following description to illustrate the technical solution of the present disclosure. The preferred embodiments of the present disclosure are described in detail below, but in addition to these detailed descriptions, the present disclosure may also have other implementations.

[0042] The PVT method is to place the seed crystal layer on the top of the crucible (low temperature zone), and place the reaction source, such as SiC powder, on the bottom of the crucible (high temperature zone). In a closed environment of high temperature and low pressure, the SiC powder is heated and sublimated, and is transferred upward to the vicinity of the seed crystal layer under the action of temperature gradient and concentration difference, and then recrystallized after reaching a supersaturated state. This method can achieve controllable growth of crystal size and specific crystal form.

[0043] It should be understood that in the process of preparing crystal structures by the PVT method, the preparation equipment plays a vital role.

[0044] refer to Figure 1 , Figure 1 FIG. 1 shows a schematic cross-sectional structure diagram of a SiC crystal structure preparation device 100. Figure 1In the environment of the preparation device 100 shown, during the process of preparing the SiC crystal structure by the PVT method, the SiC powder 101 is placed at the bottom (high temperature zone) of the crucible 102 of the preparation device. After the SiC powder 101 is decomposed into gaseous substances (main components are Si, Si2C, SiC2, etc.) by heat, it is transported from bottom to top to the low temperature zone where the seed crystal layer 103 (usually SiC seed crystal) is located with gas convection, and condenses again on the seed crystal layer to achieve homoepitaxial growth, thereby obtaining a large-sized annular SiC crystal structure.

[0045] However, in the above embodiment, the convex structure of the crucible easily causes the gas phase material to Figure 1 The dotted oval frame shown in FIG. 2 is deposited, and the shoulder deposited part cannot be separated from the SiC powder part, which results in the crucible being only disposable. In addition, the radial dimensions of the seed crystal layer and the formed SiC crystal structure in the horizontal direction are the same, which results in internal stress inside the SiC crystal structure, which results in the SiC focusing ring 200 (reference number 200) prepared after reprocessing. Figure 2 ), which reduces the yield and reliability of the SiC focusing ring.

[0046] refer to Figure 3 , Figure 3 FIG. 3 shows a cross-sectional structure diagram of another SiC crystal structure preparation device 300. Figure 3 In the process of preparing SiC crystal structure by PVT method in the preparation device 300 shown in FIG. 1 , a columnar graphite 302 is set in the center of the barrel crucible 301, and the SiC powder 303 is thermally decomposed to form an annular SiC block on the surface of the seed layer 304 and around the columnar graphite, and then the annular SiC block is reprocessed to obtain a SiC focusing ring (see FIG. 1 ). Figure 2 ).

[0047] However, in the above embodiment, after the deposition is completed, the columnar graphite and the deposited annular SiC block are difficult to separate. In addition, when the radial width of the seed layer and the deposited annular SiC block in the horizontal direction is similar, the annular SiC block will generate internal stress, which is easy to produce cracks and defects after processing. Furthermore, the diameter of the SiC focusing ring prepared by the above method is too low (<60mm), which is difficult to be used in practice, and the cost of preparing large-sized single crystal SiC is too high and the cycle is too long.

[0048] Based on one or more of the above problems, the present disclosure provides a crystal structure and a preparation method and a preparation device thereof, which can reduce manufacturing costs and improve the yield and reliability of the crystal structure. Figure 4 , Figure 5 , Figure 6 and Figure 7 , Figure 4 A schematic diagram of a crystal structure preparation device 400 provided in one embodiment of the present disclosure; Figure 5 for Figure 4 The enlarged schematic diagram of the local structure of the preparation device on the XZ plane is shown in FIG.

[0049] Figure 6 A schematic diagram of a structure in which the bottom surface of the annular reaction body provided in another embodiment is a disc-shaped structure; Figure 7 This is a schematic diagram of the structure in which the heating device surrounds the annular reaction body.

[0050] Before introducing the above-mentioned preparation device 400 in detail, various directions that may be used in the following description are defined first. In the present disclosure, the stacking direction of multiple structures in the preparation device 400 is defined as a first direction (i.e., the Z-axis direction). In a plane perpendicular to the Z direction, an intersecting second direction (i.e., the X-axis direction) and a third direction (i.e., the Y-axis direction) are defined. In some embodiments, the X-axis direction, the Y-axis direction, and the Z-axis direction may be perpendicular to each other in pairs. Here, the X-axis direction and the Z-axis direction constitute a first plane, i.e., an XZ plane; the X-axis direction and the Y-axis direction constitute a second plane, i.e., an XY plane.

[0051] refer to Figure 4 The crystal structure preparation device 400 includes: a furnace body 401; the furnace body 401 includes an installation cavity with an opening; a furnace cover 402; the furnace cover 402 is arranged at the opening of the installation cavity; a furnace core 403; the furnace core 403 is arranged in the installation cavity and forms an annular cavity with the side wall of the installation cavity; a cooling device 404; the cooling device 404 is arranged in the installation cavity and is located between the furnace cover 402 and the furnace core 403; a rotating shaft (Axis) 405; the rotating shaft 405 passes through the furnace cover 402 and is fixedly connected to the cooling device 404; wherein the rotating shaft 405 can drive the cooling device 404 to move relative to the annular cavity.

[0052] The furnace body 401 includes a side wall and a bottom surface, and the side wall of the furnace body and the bottom surface of the furnace body surround and form an installation cavity. The shape of the furnace body in the XZ plane and / or the XY plane can be circular, square, rectangular or any other suitable shape. The material of the furnace body includes but is not limited to stainless steel. The furnace cover 402 is used to seal the opening of the installation cavity, and its shape must match the opening of the installation cavity. The material of the furnace cover includes but is not limited to stainless steel.

[0053] The shape of the furnace core 403 can be selected and set according to actual needs, such as a rectangular parallelepiped, a cube, etc. The material of the furnace core includes but is not limited to stainless steel. It should be noted that the furnace core can be a solid structure or a hollow structure with an inner cavity; in some possible embodiments, when the furnace core is a hollow structure with an inner cavity, the inner cavity can be a vacuum cavity, or the inner cavity is filled with a heat-insulating material. In the embodiment of the present disclosure, the overall size of the furnace core 403 can be determined or selected based on the required size of the annular cavity, and the present disclosure does not limit this.

[0054] The cooling device 404 can be used to control the local temperature in the installation cavity on the one hand, and can also be used to fix the substrate on the other hand (described in detail below). The shape of the cooling device can be a disc, a strip, etc. In some possible embodiments, the cooling device includes a conductive structure, and during the cooling process, the temperature of the substrate connected to the conductive structure is reduced by the conductive structure. The thermal conductivity of the conductive structure is greater than the thermal conductivity of the substrate, so that the temperature on the substrate can be quickly reduced.

[0055] One end of the rotating shaft 405 is connected to the cooling device 404, and the other end can be connected to an external device to control the activities of the cooling device, such as movement and / or rotation. The manufacturing and use of the rotating shaft are relatively mature in the relevant technology and will not be described here.

[0056] Continue to refer Figure 4 The preparation device 400 further includes a heat insulating device 406, which is disposed in the installation cavity, and covers the side wall of the installation cavity, the bottom surface of the installation cavity, the surface of the furnace core, and the surface of the furnace cover on one side close to the installation cavity. Here, the heat insulating device 406 has the functions of heat preservation and heat insulation. The material of the heat insulating device includes but is not limited to graphite. It should be noted that during the use of the preparation device, in order to ensure the heat preservation and heat insulation effect of the heat insulating device, it needs to be replaced after a certain number of uses.

[0057] refer to Figure 5 The preparation device 400 also includes: an annular reaction body 407, which includes a side wall and a bottom surface; the annular reaction body 407 is placed in the annular cavity, and the opening of the annular reaction body 407 is arranged toward the cooling device 404; wherein the annular reaction body 407 includes a first crucible body 4071 (i.e., a top crucible, TopCrucible) and a second crucible body 4072 (i.e., a bottom crucible, Bottom Crucible) stacked in a first direction (such as the Z-axis direction); the first crucible body 4071 and the second crucible body 4072 can be separated at the connection between the two.

[0058] In this way, after the preparation of the crystal structure is completed in the annular reaction body 407, the first crucible body 4071 and the second crucible body 4072 can be separated, so that the second crucible body and the remaining raw materials in the second crucible body can be reused to avoid the one-time use of the annular reaction body and raw materials, thereby reducing manufacturing costs.

[0059] In some embodiments, the first crucible body may include the side wall of the annular reaction body, and the second crucible body may include the bottom surface of the annular reaction body; in this case, the side wall of the annular reaction body is not fixedly connected to the bottom surface of the annular reaction body, that is, the side wall and the bottom surface can be split at the connection between the side wall and the bottom surface. In other embodiments, the side wall is split into two parts, namely a first part and a second part, wherein the first crucible body may include the first part of the side wall of the annular reaction body, and the second crucible body may include the second part of the side wall of the annular reaction body and the bottom surface of the annular reaction body; in this case, the first part of the side wall and the second part of the side wall are not fixedly connected, that is, the side wall and the bottom surface can be split at the connection between the first part of the side wall and the second part of the side wall. In this case, the second part of the side wall is fixedly connected to the bottom surface. In other embodiments, the relative relationship between the first crucible body, the second crucible body, and the side wall and the bottom surface of the annular reaction body can also be divided in other ways, which will not be repeated here.

[0060] In order to understand this solution more clearly, the embodiments of the present disclosure and the attached Figure 5 In the embodiment, the first crucible body 4071 includes the first part of the side wall of the annular reaction body, and the second crucible body 4072 includes the second part of the side wall of the annular reaction body and the bottom surface of the annular reaction body. However, it should be understood that the following description of the structural division of the annular reaction body is only used to illustrate the present disclosure and is not used to limit the scope of the present disclosure.

[0061] Continue to refer Figure 5 The side wall and the bottom surface of the annular reaction body 407 surround and form a cavity 4073, and the opening of the cavity 4073 is arranged toward the cooling device 404. Here, the cavity 4073 is used to place the reaction source 408. In some embodiments, the material of the first crucible body 4071 and the second crucible body 4072 includes but is not limited to graphite.

[0062] In the embodiment of the present disclosure, the first crucible body 4071 and the second crucible body 4072 can be connected by bolts, riveting, or interlocking. In this way, different connection methods can be used in different application scenarios to reduce the risk of damage to the first crucible body and / or the second crucible body, thereby improving the reliability and utilization rate of the first crucible body and / or the second crucible body.

[0063] In some embodiments, the connection between the first crucible body 4071 and the second crucible body 4072 on the inner side wall of the annular reaction body 407 is kept smooth, so as to prevent the crystal structure from being deposited at the connection between the two and avoid the problem that the crystal structure and the reaction source cannot be separated. In some embodiments, graphite paper is disposed between the connection between the first crucible body 4071 and the second crucible body 4072 to facilitate separation of the first crucible body 4071 and the second crucible body 4072.

[0064] In some specific embodiments, after each crystal structure is prepared, the crystal structure can be taken out by disassembling or breaking the first crucible. In other words, the first crucible can be replaced after each crystal structure is prepared. That is, after each crystal structure is prepared, there is no need to replace the second crucible, so that the utilization rate of the second crucible can be improved and the manufacturing cost can be reduced.

[0065] In some possible embodiments, the cross-sectional shape of the annular reaction body 407 on the XZ plane includes a double U-shaped shape; the cross-sectional shape of the side wall of the annular reaction body 407 on the XY plane includes a circular ring; the cross-sectional shape of the bottom surface of the annular reaction body 407 on the XY plane includes a circular ring (refer to Figure 5 ) or disc-shaped (reference Figure 6 ).

[0066] It should be understood that when depositing large-size crystal structures, the annular side walls of the annular reactor are prone to produce uneven thermal field distribution, causing the crystal structure to deform or generate stress, which may cause damage to the side walls of the annular reactor at high temperatures or during cooling. In this case, when the bottom surface of the annular reactor is set to a disc-shaped structure, the structural strength of the second crucible body (i.e., the bottom crucible) can be effectively enhanced, so that heat can be quickly conducted, thereby making the thermal field distribution of the side walls of the annular reactor and the reaction source in the cavity of the annular reactor more uniform, thereby reducing the risk of damage to the annular reactor. In addition, the uniform thermal field distribution can also improve the uniformity of crystal structure deposition, thereby improving the quality and reliability of the crystal structure.

[0067] In some embodiments, reference Figure 4 The preparation device 400 further includes a heating device 409, which is disposed in the annular cavity. The heating device 409 is U-shaped on the XZ plane; the middle area of ​​the heating device is used to place the annular reaction body 407. Figure 5 The heating device 409 surrounds the side wall and bottom surface of the annular reaction body 407, and is used to control the temperature of the cavity 4073 of the annular reaction body 407 by controlling the temperature of the side wall and bottom surface of the annular reaction body 407. It should be noted that the heating device 409 surrounds all the side walls and bottom surface of the annular reaction body 407, but does not include the opening side of the annular reaction body.

[0068] refer to Figure 7 The annular reaction body 407 includes a first side wall 4074, a second side wall 4075 and a bottom surface 4076. The heating device 409 surrounds the first side wall 4074, the second side wall 4075 and the bottom surface 4076, so that the temperature field in the cavity of the annular reaction body 407 can be balanced.

[0069] In this way, the heating device can be controlled to form a high temperature zone on the second crucible body side of the preparation device 400. Further, after the reaction source 408 is placed in the cavity of the annular reaction body, the reaction source 408 can be heated by the heating device 409, so that the reaction source 408 is heated to gasify, sublimate or decompose, etc., to generate an intermediate gas phase substance. In practical applications, the working mode of the heating device 409 can be resistance wire heating, eddy current induction heating, etc., which is not limited in the present disclosure.

[0070] In some embodiments, reference Figure 5 The preparation device 400 also includes a substrate 410, which is fixedly arranged on a side of the cooling device 404 away from the rotating shaft 405; and a seed layer 411, which is fixedly arranged on a side of the substrate 410 away from the cooling device 404; wherein the surface of the seed layer 411 away from the substrate 410 covers the opening of the annular reaction body 407.

[0071] The material of the substrate 410 includes graphite. The thickness, size and shape of the substrate 410 can be set according to actual needs, and the present disclosure does not limit it. The material of the seed layer 411 can be different based on different reaction sources; in some possible embodiments, the reaction source is SiC powder, and the material of the seed layer is SiC material.

[0072] In the embodiment of the present disclosure, in order to improve the reliability of the manufacturing device, the shape of the substrate can be set to be a disc; the substrate 410 extends in the X-axis and / or Y-axis direction to the position directly above the opening of the annular reaction body 407 in the Z-axis direction. In some possible embodiments, the cooling device 404 and the substrate 410 have the same width in the X-axis and / or Y-axis direction, and both extend to the position directly above the opening of the annular reaction body 407 in the Z-axis direction.

[0073] In some embodiments, the cross-sectional shape of the seed layer 411 on the XY plane includes a circular ring or a circular shape. Figure 4 The cross-sectional shape of the seed layer 411 shown in FIG. 4 on the XY plane is a circular ring.

[0074] In the disclosed embodiment, the seed layer 411 is used to guide crystal growth, reduce defects, improve crystal quality, accelerate the growth process, control crystal morphology, achieve a specific crystal structure, and improve production efficiency. Figure 5 As shown, in the crystal structure preparation device 400, the seed crystal layer 411 is placed on the open side of the annular reaction body 407; after the reaction source 408 is heated and vaporized, sublimated or decomposed, the temperature is controlled by the cooling device and the heating device, and a crystal structure 412 is formed on the surface of the seed crystal layer 411 on one side facing the opening of the annular reaction body 407.

[0075] In some possible embodiments of the present disclosure, the cooling device 409 is used to lower the temperature on the side close to the seed crystal layer 411 to form a low-temperature zone on the side of the first crucible body of the preparation device 400, thereby creating a temperature difference between the temperature on the side close to the reaction source in the cavity of the annular reaction body (high-temperature zone) and the temperature on the side close to the seed crystal layer in the cavity (low-temperature zone), thereby allowing the vaporized reaction source to condense again on the seed crystal layer to form a crystal structure 412.

[0076] In some possible embodiments, the temperature difference between the temperature of the side of the annular reaction body close to the bottom surface of the annular reaction body and the temperature of the cooling device is in the range of 50° C. to 200° C.

[0077] Here, the width of the seed layer 411 in the second direction is greater than the width of the opening of the annular reaction body 407 in the X-axis. Figure 5 The width of the opening of the annular reaction body 407 in the X-axis direction is a first width L1, and the width of the seed layer 411 in the X-axis direction is a second width L2. Here, the second width L2 is greater than the first width L1, that is, L2>L1.

[0078] It should be understood that after the reaction source 408 is decomposed by heat, based on the influence of gas convection and temperature difference, a crystal structure 412 is formed on the surface of the seed layer 411 on the opposite sides along the Z-axis direction, which is close to the opening side of the annular reaction body 407 (i.e., the lower surface of the seed layer). When the first width L1 of the annular reaction body 407 is less than the second width L2 of the seed layer 411, the internal stress generated by the crystal structure 412 during the deposition process and the cooling process can be reduced, thereby reducing the generation of defects and cracks in the crystal structure 412 and improving the quality of the crystal structure.

[0079] In some specific embodiments, the second width L2 is greater than 1.2 times the first width L1, that is, L2 ≥ 1.2L1, which can further reduce the generation of defects and cracks in the edge region of the crystal structure 412.

[0080] In some embodiments, the width of the seed layer 411 in the X-axis direction is less than or equal to the width of the substrate 410 in the X-axis direction; further, the width of the opening of the annular reaction body in the X-axis direction is less than the width of the substrate 410 in the X-axis direction.

[0081] In some possible embodiments, the width of the substrate 410 in the X-axis direction is a third width L3, wherein the second width L2 of the seed layer 411 is less than or equal to the third width L3 of the substrate 410, that is, L2≤L3; the first width L1 of the opening of the annular reaction body 407 is less than the third width L3 of the substrate 410, that is, L1<L3; that is, L1<L2≤L3.

[0082] In some possible embodiments, the diameter of the substrate 410 is D, and the value range of D is 50 mm to 400 mm. The second width L2 of the seed layer 411 in the X-axis direction is in the range of L2>0.06D to 0.6D. The first width L1 of the opening of the annular reaction body in the X-axis direction is in the range of L1=0.05D to 0.5D, so as to further reduce the internal stress generated in the crystal structure during the deposition process and the cooling process, and reduce the generation of defects and cracks in the crystal structure.

[0083] In some possible embodiments, the reaction source 408 may be a crystalline powder, such as SiC powder, aluminum nitride (AlN) powder, tantalum carbide (TaC), boron carbide (B4C), zinc selenide (ZnSe) powder, or other carbide powders, nitride powders, etc.

[0084] In some possible embodiments, the crystal structure 412 includes SiC, AlN, TaC, B4C or ZnSe, etc. In some specific embodiments, the crystal structure 412 is SiC, which is a polycrystalline structure, the grain size of SiC ranges from 0.1 mm to 50 mm, and the crystal types of SiC include 4H crystal and 6H crystal.

[0085] It should be noted that the rotating shaft 405 is fixedly connected to the cooling device 404, the cooling device 404 is fixedly connected to the substrate 410, and the substrate 410 is fixedly connected to the seed crystal layer 411. Therefore, the rotating shaft 405 can drive the cooling device 404, the substrate 410 and the seed crystal layer 411 to move, such as rotate and / or move, through an external motor.

[0086] In some possible embodiments, the rotating shaft 405 can be used to drive the cooling device 404, the substrate 410 and the seed crystal layer 411 to rise or fall in the Z-axis direction; and / or, the rotating shaft 405 can be used to drive the cooling device 404, the substrate 410 and the seed crystal layer 411 to rotate in a clockwise or counterclockwise direction on the XY plane.

[0087] The purpose of the rotating shaft 405 driving the cooling device 404, the substrate 410 and the seed crystal layer 411 to rise or fall in the Z-axis direction is to ensure that the temperature difference between the lower surface of the crystal structure and the reaction source is constant, thereby ensuring that the temperature field in the cavity of the annular reaction body is uniform and stable, thereby improving the stability of the crystal structure. The purpose of the rotating shaft 405 driving the cooling device 404, the substrate 410 and the seed crystal layer 411 to rotate in the clockwise or counterclockwise direction on the XY plane is to uniformly disperse the gaseous reaction source or the intermediate gas phase substance on the lower surface of the seed crystal layer (in the growth process of the crystal structure, the lower surface is the lower surface of the crystal structure), accelerate its diffusion speed, and thus promote its uniform and rapid growth; in this way, the crystal orientation of the crystal structure can be changed, the lattice distortion can be reduced, and the growth quality of the crystal structure can be improved.

[0088] Based on this, the crystal structure preparation device provided in the embodiment of the present disclosure, on the one hand, by arranging a furnace core in the installation cavity, an annular cavity is formed between the side wall of the installation cavity and the furnace core, so that the crystal structure formed in the annular cavity can be annular as a whole; on the other hand, the first crucible body and the second crucible body constituting the annular reaction body can be split at the connection between the two, thereby avoiding the disposable use of the annular reaction body to reduce the manufacturing cost. On the other hand, by setting the width of the seed layer in the first direction to be greater than the width of the cavity of the annular reaction body in the first direction, the internal stress generated in the crystal structure during the deposition process and the cooling process can be reduced, and the generation of defects and cracks can be reduced, thereby improving the quality and reliability of the crystal structure. On the other hand, by arranging a rotating shaft in the reaction device to drive the cooling device and the seed layer to rotate, the temperature field in the cavity of the annular reaction body can be ensured to be uniform and stable, thereby improving the stability of the crystal structure.

[0089] Based on the above-mentioned crystal structure preparation device, the embodiment of the present disclosure also proposes a crystal structure preparation method, and the crystal structure is prepared using the preparation device described in the above-mentioned embodiment of the present disclosure; wherein, in the process of preparing the crystal structure using the preparation device, the cooling device is driven to move relative to the annular cavity by controlling the rotating shaft.

[0090] The specific steps include: providing a crystal structure preparation device, referring to Figure 4 and Figure 5 The preparation device 400 includes a furnace body 401; a furnace cover 402; a furnace core 403; a cooling device 404 and a rotating shaft 405; the furnace body 401 includes an installation cavity with an opening; the furnace cover 402 is arranged at the opening of the installation cavity; the furnace core 403 is arranged in the installation cavity and forms an annular cavity with the side wall of the installation cavity; the cooling device 404 is arranged in the installation cavity and is located between the furnace cover and the furnace core; the rotating shaft 405 passes through the furnace cover and is fixedly connected to the cooling device; the rotating shaft 405 can drive the cooling device to move relative to the annular cavity.

[0091] In some embodiments, the method also includes: placing the annular reaction body 407 in the annular cavity, and setting the opening of the annular reaction body 407 toward the cooling device 404; wherein the annular reaction body 407 includes a first crucible body and a second crucible body stacked in a first direction; the first crucible body and the second crucible body can be split at the connection between the two; the first direction is parallel to the extension direction of the side wall of the installation cavity.

[0092] Here, the first crucible body and the second crucible body constituting the annular reaction body can be separated at the connection between the two. On the inner side wall of the annular reaction body, the first crucible body and the second crucible body remain smooth at the connection between the two. Alternatively, graphite paper is set between the connection between the first crucible body 4071 and the second crucible body 4072 to facilitate separation of the first crucible body 4071 and the second crucible body 4072.

[0093] In some embodiments, the method also includes: fixing the substrate 410 on a side of the cooling device 404 away from the rotating shaft 405; fixing the seed layer 411 on a side of the substrate 410 away from the cooling device 404, and making the surface of the seed layer 411 away from the substrate 410 cover the opening of the annular reaction body 407; setting the heat insulation device 406 in the installation cavity, and making the heat insulation device 406 cover the side wall of the installation cavity, the bottom surface of the installation cavity, the surface of the furnace core and the surface of the furnace cover on one side close to the installation cavity; and setting the heating device 409 between the annular reaction body 407 and the heat insulation device 406.

[0094] Here, the width of the seed layer 411 in the X-axis direction is greater than the width of the opening of the annular reaction body in the X-axis direction, so that the internal stress in the crystal structure can be reduced, the generation of defects and cracks in the crystal structure can be reduced, and the quality and reliability of the crystal structure can be improved. The rotating shaft 405 and the cooling device 404, the cooling device and the substrate, and the substrate and the seed layer are all fixedly connected, and the rotating shaft can drive the cooling device, the substrate and the seed layer to move, such as rotating and / or moving.

[0095] It should be understood that the order in which the annular reaction body 407, the heating device 409, and the heat insulating device 406 are placed in the preparation device can be interchanged.

[0096] In some embodiments, a reaction source is provided and placed in the cavity of the annular reaction body. The reaction source 408 can be at least one of SiC powder, AlN powder, TaC powder, B4C powder or ZnSe powder, or at least one of other carbide powders and nitride powders.

[0097] Here, after the reaction source is placed in the cavity of the annular reaction body, the top surface of the reaction source in the cavity is located on the side of the connection between the first crucible body and the second crucible body close to the bottom surface of the annular reaction body in the Z-axis direction. In other words, after the reaction source is placed in the cavity of the annular reaction body, the height of the top surface of the reaction source in the Z-axis direction is less than the height of the connection between the first crucible body and the second crucible body in the Z-axis direction. In other words, the height of the top surface of the reaction source in the Z-axis direction does not exceed the height of the interlocking part of the first crucible body and the second crucible body in the Z-axis direction.

[0098] Next, the reaction device is evacuated to make the annular reaction body in a low-pressure atmosphere; here, the vacuum degree can be set as required, for example, to 1.3 KPa or lower (such as 500 Pa, 400 Pa). And, a protective gas, such as an inert gas, is introduced into the annular reaction body. In some possible embodiments, the inert gas is argon (Ar).

[0099] The reaction temperature in the annular reaction body is raised by a heating device, and the temperature range in the annular reaction body reaches 2000°C to 2500°C. In some possible embodiments, the temperature range in the annular reaction body reaches 2200°C to 2300°C, so as to avoid too slow a deposition rate and enhance the crystal quality. And a temperature difference is maintained between the temperature of the side close to the reaction source in the annular reaction body (high temperature zone) and the temperature of the side close to the seed crystal layer in the cavity (low temperature zone), and the value range of the temperature difference is 50°C to 200°C. Then, the vaporized reaction source is condensed again on the seed crystal layer to form a crystal structure.

[0100] It should be noted that in the process of forming the crystal structure, parameters such as the distance between the lower surface of the seed layer and the top surface of the reaction source and the reaction time can be set according to actual needs. For example, the distance between the lower surface of the seed layer and the top surface of the reaction source ranges from 50 mm to 200 mm. The reaction time is 20 to 100 hours (h), etc.

[0101] In some embodiments, the diameter of the cooling device is D, and the value range of D is 50 mm to 400 mm. The radial width of the seed layer in the X-axis direction ranges from 0.06D to 0.6D and above. The radial width of the crystal structure in the X-axis direction ranges from 0.05D to 0.5D.

[0102] In some possible implementations, a sensing device may be further provided in the annular reaction body, and the sensing device is used to sense the temperature in the annular reaction body or cavity and provide feedback, so that the temperature in the annular reaction body or cavity can reach a desired temperature.

[0103] The reaction process of forming SiC is illustrated below by taking SiC as an example.

[0104] SiC powder is placed in the cavity of the annular reaction body, and the reaction temperature in the cavity of the annular reaction body is increased by a heating device, so that the SiC powder is thermally decomposed to generate SiC intermediate gas phase substances (such as Si, SiC2, Si2C, etc.), which can also be understood as intermediate gas phase substances. With the influence of gas convection and temperature difference in the cavity, the intermediate gas phase substances rise from the high temperature zone to the low temperature zone, and cool and condense into SiC crystal structure on the seed crystal layer. Among them, the decomposition chemical equations in the cavity include:

[0105] SiC(s)=Si(g)+C(s);

[0106] 2SiC(s)=SiC2(g)+Si(g);

[0107] 2SiC(s)=Si2C(g)+C(s).

[0108] The synthetic chemical equations in the cavity include:

[0109] SiC2(g)+Si(g)=2SiC(s);

[0110] Si2C(g)+SiC2(g)=3SiC(s).

[0111] Here, s represents solid, and g represents gas.

[0112] In some embodiments, the method also includes: controlling the rotating shaft 405 so that the rotating shaft 405 drives the cooling device 404, the substrate 410 and the seed crystal layer 411 to rise or fall in the Z-axis direction; and / or so that the rotating shaft 405 drives the cooling device 404, the substrate 410 and the seed crystal layer 411 to rotate in a clockwise direction or counterclockwise direction on the XY plane.

[0113] In some embodiments, the method further includes: controlling the heating device 409 to increase the temperature of the side wall and the bottom surface of the annular reaction body to control the temperature inside the annular reaction body.

[0114] In some embodiments, the method further includes: controlling the heating device 409 and / or the cooling device 404 so that the temperature difference between the temperature of the side of the annular reaction body close to the bottom surface of the annular reaction body and the temperature of the cooling device 404 is within the range of 50°C to 200°C.

[0115] In some embodiments, the method further comprises: after the preparation of the crystal structure is completed, disassembling or breaking the first crucible body to remove the crystal structure. In this way, the second crucible body can be kept intact, the utilization rate of the second crucible body can be improved, and the manufacturing cost can be reduced.

[0116] In the embodiment of the present disclosure, the overall shape of the SiC crystal structure is a circular ring. In some possible embodiments, the method further includes: re-processing the SiC crystal structure to obtain a SiC focusing ring.

[0117] Based on the above-mentioned crystal structure preparation device and preparation method, an embodiment of the present disclosure also provides a crystal structure, which is obtained using the above-mentioned preparation device and preparation method, wherein the overall shape of the crystal structure is a circular ring.

[0118] In some embodiments, the crystal structure may include polycrystalline, and the grain size of the crystal structure ranges from 0.1 mm to 50 mm.

[0119] In some embodiments, the crystal structure may include SiC, AlN, TaC, B4C, or ZnSe, among others.

[0120] In some embodiments, the crystal type of SiC includes 4H crystal and 6H crystal.

[0121] It should be understood that "one embodiment" or "an embodiment" mentioned throughout the specification means that specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present disclosure. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It should be understood that in the various embodiments of the present disclosure, the size of the serial number of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present disclosure. The serial numbers of the embodiments of the present disclosure are for description only and do not represent the advantages and disadvantages of the embodiments.

[0122] The above description is only a preferred embodiment of the present disclosure, and does not limit the patent scope of the present disclosure. All equivalent structural changes made by using the contents of the present disclosure and the drawings under the inventive concept of the present disclosure, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present disclosure.

Claims

1. A device for preparing a crystal structure, characterized in that: The preparation device comprises: A furnace body; the furnace body comprises a mounting cavity having an opening; A furnace cover; the furnace cover is arranged at the opening of the installation cavity; A furnace core; the furnace core is arranged in the installation cavity and forms an annular cavity with the side wall of the installation cavity; A cooling device; the cooling device is arranged in the installation cavity and located between the furnace cover and the furnace core; Rotating shaft; the rotating shaft passes through the furnace cover and is fixedly connected to the cooling device; Wherein, the rotating shaft can drive the cooling device to move relative to the annular cavity.

2. The preparation device according to claim 1, characterized in that: The preparation device also includes: An annular reaction body, comprising a side wall and a bottom surface; the annular reaction body is placed in the annular cavity, and the opening of the annular reaction body is arranged toward the cooling device; The annular reaction body comprises a first crucible body and a second crucible body stacked in a first direction; the first crucible body and the second crucible body can be separated at a connection point between the first direction and the side wall extension direction of the installation cavity.

3. The preparation device according to claim 2, characterized in that: The first crucible body and the second crucible body are connected by bolts, rivets or interlocking.

4. The preparation device according to claim 3, characterized in that: At the inner side wall of the annular reaction body, the connection between the first crucible body and the second crucible body is kept smooth; or, graphite paper is arranged between the connection between the first crucible body and the second crucible body.

5. The preparation device according to claim 2, characterized in that: The preparation device further comprises: a substrate fixedly arranged on a side of the cooling device away from the rotating shaft; A seed crystal layer is fixedly arranged on a side of the substrate away from the cooling device; Wherein, the surface of the seed crystal layer away from the substrate covers the opening of the annular reaction body.

6. The preparation device according to claim 5, characterized in that: The width of the seed layer in the second direction is greater than the width of the opening of the annular reaction body in the second direction; and the second direction is perpendicular to the extension direction of the side wall of the annular reaction body.

7. The preparation device according to claim 6, characterized in that: The rotating shaft drives the cooling device, the substrate and the seed crystal layer to rise or fall in the first direction; and / or, The rotating shaft drives the cooling device, the substrate and the seed crystal layer to rotate in a clockwise direction or a counterclockwise direction on a first plane; the first plane is perpendicular to the first direction.

8. The preparation device according to claim 5, characterized in that: The preparation device also includes: a heat insulation device, which is arranged in the installation cavity and covers the side wall of the installation cavity, the bottom surface of the installation cavity, the surface of the furnace core, and the surface of one side of the furnace cover close to the installation cavity; and The heating device is arranged between the annular reaction body and the heat insulation device.

9. A method for preparing a crystal structure, characterized in that: The crystal structure is prepared using the preparation device described in any one of claims 1 to 8; In the process of preparing the crystal structure by using the preparation device, the cooling device is driven to move relative to the annular cavity by controlling the rotating shaft.

10. The preparation method according to claim 9, characterized in that: The method further comprises: Placing an annular reaction body in the annular cavity, and arranging the opening of the annular reaction body toward the cooling device; The annular reaction body comprises a first crucible body and a second crucible body stacked in a first direction; the first crucible body and the second crucible body can be separated at a connection point between the first direction and the side wall extension direction of the installation cavity.

11. The preparation method according to claim 10, characterized in that: The method further comprises: The substrate is fixedly arranged on a side of the cooling device away from the rotating shaft; The seed crystal layer is fixedly arranged on a side of the substrate away from the cooling device, and the surface of the seed crystal layer away from the substrate covers the opening of the annular reaction body; Arranging a heat insulation device in the installation cavity, and making the heat insulation device cover the side wall of the installation cavity, the bottom surface of the installation cavity, the surface of the furnace core, and the surface of one side of the furnace cover close to the installation cavity; and The heating device is arranged between the annular reaction body and the heat insulating device.

12. The preparation method according to claim 11, characterized in that: The method further comprises: The rotating shaft is controlled so that the rotating shaft drives the cooling device, the substrate and the seed crystal layer to rise or fall in the first direction; and / or the rotating shaft drives the cooling device, the substrate and the seed crystal layer to rotate in a clockwise or counterclockwise direction on a first plane; the first plane is perpendicular to the first direction.

13. The preparation method according to claim 11, characterized in that: The method further comprises: By controlling the heating device, the temperature of the side wall and the bottom surface of the annular reaction body is increased to control the temperature inside the annular reaction body.

14. The preparation method according to claim 13, characterized in that: The method further comprises: The heating device and / or the cooling device are controlled so that the temperature difference between the temperature of the side of the annular reaction body close to the bottom surface of the annular reaction body and the temperature of the cooling device is within the range of 50° C. to 200° C.

15. The preparation method according to claim 14, characterized in that: The method further comprises: After the preparation of the crystal structure is completed, the first crucible is disassembled or broken to take out the crystal structure.

16. A crystal structure prepared by the method for preparing a crystal structure according to any one of claims 9 to 15, characterized in that: The overall shape of the crystal structure is ring-shaped.

17. The crystal structure according to claim 16, characterized in that The crystal structure includes silicon carbide, aluminum nitride, tantalum carbide, boron carbide, and zinc selenide.

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