CN215593242U - Device for preparing crucible with polycrystalline block - Google Patents
Device for preparing crucible with polycrystalline block Download PDFInfo
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- CN215593242U CN215593242U CN202121888892.5U CN202121888892U CN215593242U CN 215593242 U CN215593242 U CN 215593242U CN 202121888892 U CN202121888892 U CN 202121888892U CN 215593242 U CN215593242 U CN 215593242U
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Abstract
The application discloses a device for preparing crucible with polycrystal piece, it includes crucible subassembly and is used for heating the heating member of crucible subassembly, the crucible subassembly is located the zone of heating that the heating member formed, just the heating member can form high temperature region and low temperature zone, the crucible subassembly includes the crucible body, the crucible body is including the charge portion that is located high temperature region and the crystal growth portion that is located low temperature zone, the charge portion is located inside the crucible body, the crystal growth portion includes the diapire of crucible body and at least part the lateral wall of crucible body, the powder in the charge portion sublimates to the crystal growth portion to in the crystal growth portion crystallization becomes polycrystal piece; the device also comprises a driving component, wherein the driving component is used for driving the crucible body to move so that at least part of the side wall of the crucible passes through the low-temperature zone.
Description
Technical Field
The application relates to a device for preparing a crucible with a polycrystalline block, and belongs to the technical field of semiconductors.
Background
Wide bandgap semiconductor materials typified by silicon carbide (SiC) and gallium nitride (GaN) are the third generation semiconductor materials following silicon (Si) and gallium arsenide (GaAs). Among them, silicon carbide crystal is one of the important third-generation semiconductor materials, and has excellent performance in the aspects of high temperature, high frequency, high power, radiation resistance and the like, and silicon carbide-based devices have been widely applied in multiple fields such as military affairs, civil affairs, aerospace and the like, and are the key fields of scientific and technical research of various countries.
At present, the most widely adopted method for growing silicon carbide crystals is a physical vapor transport method, namely, SiC powder is used as a raw material in a crucible, a vapor substance generated by sublimation of the SiC powder is transported to a SiC seed crystal with a slightly lower temperature under the action of a temperature gradient, and the SiC seed crystal is crystallized to form bulk SiC crystals.
However, since the sublimation temperature of silicon is lower than that of carbon, the partial pressure of silicon vapor in the gas phase is much higher than that of carbon vapor, and therefore, during the crystal growth, the SiC powder inevitably undergoes graphitization, i.e., graphite particles remain in the SiC powder, and since the temperature is highest near the crucible wall, the region where graphitization is most severe is located near the crucible wall. In addition, the bulk density of the SiC powder is only 1.35g/cm-3And because of the left and right sides, large gaps exist among the particles, and the particles are isolated from one another, so that in the process of conveying gas to the seed crystal, the graphite particles are extremely easy to be wrapped on the surface of the crystal by the airflow to form a wrapping defect, and the quality and the yield of the SIC are influenced.
At present, in order to reduce the defects of carbon inclusions caused by SIC powder, a silicon carbide polycrystalline block can be used as a crystal growth raw material. However, since the bulk density of the SIC polycrystalline block is high, the gas phase generated after sublimation of the silicon carbide located inside has a certain resistance during sublimation, and when the gas phase encounters a low-temperature raw material located on the surface of the SIC polycrystalline block during the rising process, crystal nucleus crystallization growth may directly occur at the raw material, thereby continuously consuming the gas phase generated from the SIC polycrystalline block, and reducing the utilization efficiency of the SIC polycrystalline block and the production yield of the silicon carbide single crystal.
SUMMERY OF THE UTILITY MODEL
In order to solve the above problems, the present application proposes an apparatus for preparing a crucible having a polycrystalline block. The device can make the sublimed gaseous phase of powder transport the diapire of crucible body and the lateral wall of at least partial crucible body form the polycrystal piece, thereby make the polycrystal piece that forms be one end open-ended hollow tubular structure, hollow channel of hollow tubular structure can regard as the passageway that single crystal growth in-process gaseous phase transported, for gaseous phase provides bigger transport space, the gaseous phase that the inside raw materials that has reduced and is close to the crucible wall produced transports the resistance, the gaseous phase that has reduced inside raw materials and the contact area of surperficial polycrystal piece in the in-process of transmission, the utilization efficiency of polycrystal piece and the yield of single crystal have been improved.
According to an aspect of the present application, there is provided an apparatus for preparing a crucible having a polycrystalline block, comprising a crucible assembly and a heating member for heating the crucible assembly, the crucible assembly being located in a heating region formed by the heating member, and the heating member being capable of forming a high-temperature region and a low-temperature region,
the crucible assembly comprises a crucible body, the crucible body comprises a charging part and a crystal growth part, the charging part is located in the crucible body, the crystal growth part is located in the low-temperature region, the charging part is located in the crucible body, the crystal growth part comprises a bottom wall of the crucible body and at least part of a side wall of the crucible body, powder in the charging part is sublimated to the crystal growth part, and the powder is crystallized into a polycrystalline block in the crystal growth part;
the device also comprises a driving component, wherein the driving component is used for driving the crucible body to move so that at least part of the side wall of the crucible passes through the low-temperature zone.
Optionally, the drive assembly includes a rolling region having a slope to roll the sidewall of the crucible along the rolling region.
Optionally, the drive assembly comprises a plurality of support tables which together form the rolling region, the height of each support table being independently adjustable to provide the rolling region with a gradient.
Optionally, the driving assembly further includes a first baffle and a second baffle, the first baffle and the second baffle are higher than each of the supporting tables, and the first baffle and the second baffle are respectively disposed on two opposite sides of the rolling area along the rolling direction of the crucible.
Optionally, a screw is connected below each support platform,
the driving assembly further comprises a supporting frame, a plurality of threaded openings are formed in the supporting frame, and each threaded opening is matched with the corresponding screw rod, so that the supporting table can ascend or descend.
Optionally, the length of the rolling region is 2n pi r +2r, where n is an integer different from zero, and r is a radius of the crucible.
Optionally, the crucible assembly comprises a porous graphite plate inside the crucible body and a charging bucket arranged between the porous graphite plate and the bottom wall of the crucible, the opening of the charging bucket is connected with one side of the porous graphite plate,
a cavity structure is formed between the charging barrel and the porous graphite plate, and the cavity structure forms the charging part.
Optionally, the crucible assembly further comprises a crucible cover and a pressing plate member, a boss is arranged on the side wall of the crucible, the graphite plate is arranged between the pressing plate member and the boss,
when the crucible cover covers the crucible body, the crucible cover compresses the pressing plate piece, and the graphite plate is fixed between the pressing plate piece and the boss.
Optionally, the opening of the charging barrel is provided with an internal thread, one side of the graphite plate close to the bottom wall of the crucible body is provided with a mounting ring, the mounting ring is provided with an external thread, and the internal thread and the external thread are matched to connect the charging barrel and the graphite plate.
Optionally, the ratio of the outer diameter of the charging barrel to the inner diameter of the crucible is 0.5-0.7: 1; and/or
The ratio of the distance between the porous graphite plate and the bottom wall of the crucible body to the height of the crucible body is 0.5-0.8: 1.
Benefits that can be produced by the present application include, but are not limited to:
1. the device for preparing the crucible with the polycrystalline blocks, which is provided by the application, drives the crucible body to move by arranging the driving assembly, so that at least part of the side wall of the crucible body passes through the low temperature region, the side wall and the bottom wall of the crucible body are used as a crystal growth part to be in the low temperature region, the gas phase sublimated by powder is conveyed to the bottom wall of the crucible body and at least part of the side wall of the crucible body to form the polycrystalline blocks, therefore, the formed polycrystalline block is of a hollow cylindrical structure with an opening at one end, the hollow channel of the hollow cylindrical structure can be used as a channel for transporting gas phase in the process of growing single crystals, a larger transporting space is provided for the gas phase, the transporting resistance of the gas phase generated by the internal raw materials close to the crucible wall is reduced, the contact area of the gas phase generated by the internal raw materials and the polycrystalline block on the surface in the transporting process is reduced, and the utilization efficiency of the polycrystalline block and the yield of the single crystals are improved.
2. The application provides a device for preparing crucible with polycrystal piece, include a plurality of brace tables through setting up drive assembly, and the height homoenergetic of every brace table can independently be adjusted, thereby can freely control the roll direction of crucible, roll to the other end when the crucible is followed the one end in roll district, through the height of adjustment brace table, can roll the crucible back to initial position along former route, realize the reciprocal roll of crucible, when guaranteeing the growth time of polycrystal piece, the length of rolling platform has been shortened, the space has been saved.
3. The utility model provides a device for preparing crucible with polycrystal piece sets up first baffle and second baffle respectively through the relative both sides in the roll district, and the height that highly all is higher than every brace table of first baffle and second baffle to provide when rolling to the both ends in roll district for the crucible and block the power, prevent that the crucible from rolling from the roll district.
4. The utility model provides a device for preparing crucible that has polycrystal piece all is connected with the screw rod through the below that sets up every brace table to mutually support with the screw thread mouth on the support frame, realize the stable lift of brace table.
5. The utility model provides a device for preparing crucible with polycrystalline block, through the length that sets up the roll district, when making the crucible roll to the other end from the one end in roll district, accomplish the long crystal of the whole circle of crucible lateral wall to make the different positions thickness of the polycrystalline block of crucible lateral wall more even, and then guarantee that the follow-up gaseous phase that forms when long brilliant raw materials is more even, be favorable to improving the single crystal quality of growth.
6. According to the device for preparing the crucible with the polycrystalline block, a cavity structure is formed between the charging barrel and the porous graphite plate, so that a containing space is provided for powder; meanwhile, the pores of the porous graphite plate are favorable for the transmission of silicon carbide gas phase, and the porous graphite plate can be used as a carbon source for supplement.
7. The device for preparing crucible with polycrystalline block that this application provided through setting up clamp plate spare and boss, fixes porous graphite plate between clamp plate spare and boss, prevents that the graphite plate from rocking from appearing in the in-process of preparing polycrystalline block, and simple structure, the placing and taking out of the porous graphite plate of being convenient for.
8. According to the device for preparing the crucible with the polycrystalline blocks, the ratio of the outer diameter of the charging barrel to the inner diameter of the crucible is set, so that the charging barrel can be ensured to contain enough powder, the load force of a graphite plate is reduced, the side wall of the crucible outside the charging barrel can be used as a crystal growth part to grow the silicon carbide polycrystalline blocks, and the coverage area of the polycrystalline blocks is increased; through setting up the distance between porous graphite board and the crucible body diapire, and then control silicon carbide polycrystal piece's height, reserve the crucible lateral wall that does not cover the polycrystal piece of suitable area, provide supplementary carbon source for follow-up growth single crystal.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:
FIG. 1 is a schematic view of a crucible body of an apparatus for manufacturing a crucible having a polycrystalline block according to example 1 of the present application, which is rolled;
FIG. 2 is a schematic view showing an initial state of an apparatus for manufacturing a crucible having a polycrystalline block according to example 1 of the present application;
FIG. 3 is a schematic view of a crucible body structure according to example 1 of the present application;
FIG. 4 is an XRD diffraction pattern of single crystal # 3 to which example 4 of the present application relates;
fig. 5 is an XRD diffraction pattern of single crystal D2# designed in example 4 of this application.
List of parts and reference numerals:
1. a crucible body; 2. powder material; 3. a polycrystalline block; 4. a support table; 5. a first baffle plate; 6. a second baffle; 7. a screw; 8. a support frame; 9. a threaded opening; 10. a power plant; 11. a computer control system; 12. a porous graphite plate; 13. a charging barrel; 14. a platen member; 15. a boss; 16. and (5) heating the furnace.
Detailed Description
In order to more clearly explain the overall concept of the present application, the following detailed description is given by way of example in conjunction with the accompanying drawings.
In order that the above objects, features and advantages of the present application can be more clearly understood, the present application will be described in further detail with reference to the accompanying drawings and detailed description. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, however, the present application may be practiced in other ways than those described herein, and therefore the scope of the present application is not limited by the specific embodiments disclosed below.
In addition, in the description of the present application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", and the like, indicate orientations and positional relationships based on those shown in the drawings, are only for convenience of description and simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present application.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.
In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; the connection can be mechanical connection, electrical connection or communication; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.
In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The kind of the polycrystalline block prepared by the apparatus is not limited, and for example, it may be a silicon carbide polycrystalline block, a gallium nitride polycrystalline block, or the like, as long as a single crystal can be grown from the polycrystalline block. In the examples of the present application, a polycrystalline silicon carbide block is taken as an example, but not limited to a polycrystalline silicon carbide block, and the prepared crucible having the polycrystalline block is used for preparing a silicon carbide single crystal, such as various crystal forms of 4H, 6H, and the like. Correspondingly, the powder may be silicon carbide powder or a mixture of carbon powder and silicon powder, and the following examples illustrate high purity carbon powder and silicon powder (both at 99.999%).
In addition, in the prior art, the crucible is generally placed in a heating furnace for heating, a heating coil is disposed outside the heating furnace, the heating temperatures at two ends of the heating coil are lower than the heating temperature at the middle part, that is, the middle part of the heating furnace is a high temperature region, the upper and lower ends are low temperatures, and axial temperature gradients are respectively formed from the middle part to the upper end and from the middle part to the lower end. In the embodiment of the application, in order to enable the side wall of the crucible to be positioned in the low-temperature region, the crucible is transversely placed in the heating furnace.
Example 1
As shown in fig. 1 to 3, the embodiment of the present application discloses an apparatus for preparing a crucible having a polycrystalline block 3, which includes a crucible assembly and a heating member for heating the crucible assembly, the crucible assembly being located in a heating region formed by the heating member, and the heating member being capable of forming a high temperature region and a low temperature region, the crucible assembly including a crucible body 1, the crucible body 1 including a charging portion located in the high temperature region and a crystal growth portion located in the low temperature region, the charging portion being located inside the crucible body 1, the crystal growth portion including a bottom wall of the crucible body 1 and at least a part of a side wall of the crucible body 1, a powder material 2 in the charging portion sublimes into the crystal growth portion and is crystallized into the polycrystalline block 3 in the crystal growth portion; the device also comprises a driving component which is used for driving the crucible body 1 to move so that at least part of the side wall of the crucible passes through the low temperature zone. The crucible body 1 is driven to move by arranging the driving assembly, so that at least part of the side wall of the crucible body 1 passes through the low temperature zone, the side wall and the bottom wall of the crucible body 1 are used as a crystal growth part and are positioned in the low temperature zone, the gas phase sublimated by the powder 2 is conveyed to the bottom wall of the crucible body 1 and at least part of the side wall of the crucible body 1 to form a polycrystalline block 3, therefore, the formed polycrystalline block 3 is of a hollow cylindrical structure with an opening at one end, the hollow channel of the hollow cylindrical structure can be used as a channel for transporting gas phase in the growth process of the silicon carbide single crystal, a larger transporting space is provided for the gas phase, the transporting resistance of the gas phase generated by the internal silicon carbide raw material close to the crucible wall is reduced, the contact area of the internal silicon carbide raw material and the surface silicon carbide polycrystalline block 3 in the transporting process is reduced, and the utilization efficiency of the silicon carbide polycrystalline block 3 and the yield of the silicon carbide single crystal are improved.
Specifically, the side wall of the crucible main body 1 may be entirely used as a crystal growth portion for growing the polycrystalline ingot 3, or may be partially used as a crystal growth portion for growing the polycrystalline ingot 3. Preferably, in order to supplement the side wall of the crucible with a C source during the growth of the polycrystalline ingot 3, and to maintain a good C/Si ratio, and to prevent polytype from occurring due to too low C partial pressure when the side wall is used as a raw material for single crystal growth, the polycrystalline ingot 3 is grown with a part of the side wall of the crucible body 1 being used as a growth portion. Here, the polycrystalline ingot 3 grown along the side wall of the partial crucible body 1 may be an annular polycrystalline ingot grown along the circumferential direction of the partial crucible side wall, or an arc-shaped plate-shaped polycrystalline ingot grown along the axial direction of the partial crucible side wall. Preferably, the polycrystalline block 3 growing along a part of the side wall of the crucible is an annular polycrystalline block 3 growing along the circumferential direction of a part of the side wall of the crucible, and the arrangement mode can ensure that when the crucible with the polycrystalline block 3 is prepared and used as a crucible for crystal growth, gas phases at different positions in the radial direction in the crucible are more uniform, so that the thickness of the obtained single crystal is more uniform.
Specifically, the driving assembly can drive the crucible to rotate or roll, so long as at least part of the side wall of the crucible can pass through the low temperature zone. When the drive crucible rotated, can use the one end of manipulator centre gripping crucible, drive the crucible and rotate, made sublimed gaseous phase transmit to the lateral wall and the diapire department of crucible.
Specifically, the position of the charging portion is not limited in this embodiment, and may be located at one end of the crucible, or may be located in the middle of the crucible in the axial direction; can be arranged close to the side wall of the crucible or at the radial center of the crucible.
Specifically, since the rate of formation of polycrystals is low at the initial stage, small polycrystalline blocks 3 may be embedded in the growth portion to grow as growth centers in order to increase the growth rate of polycrystals.
In one embodiment, the drive assembly includes a rolling region having a slope to cause the sidewall of the crucible to roll along the rolling region. The side wall of the crucible rolls along the rolling area, so that the side wall of the crucible sequentially passes through the low temperature area, and the gas phase sublimated by the powder 2 is transmitted to the side wall of the crucible under the action of the temperature gradient to form the polycrystalline block 3.
With continued reference to fig. 1-2, as one embodiment, the drive assembly includes a plurality of support tables 4, the plurality of support tables 4 collectively forming a rolling area, and the height of each support table 4 is independently adjustable to provide a grade to the rolling area. Including a plurality of brace tables 4 through setting up drive assembly, and every brace table 4's height homoenergetic is independently adjusted to can freely control the roll direction of crucible, when the crucible rolls to the other end from the one end in roll district, through the height of adjustment brace table 4, can roll the crucible back to initial position along former route, realize the reciprocal roll of crucible, when guaranteeing polycrystalline block 3's growth time, shortened the length of roll platform, saved the space.
Specifically, in the present embodiment, the number of the support tables 4 is not limited as long as the crucible main body 1 can roll. Specifically, the present embodiment does not limit the distance between the adjacent support tables 4, as long as the crucible can be prevented from falling from the gap between the support tables 4 and the rolling of the crucible can be achieved.
Specifically, in order to increase the friction between the crucible side wall and the support table 4, protect the crucible outer side wall, and prevent uneven growth caused by the crucible slipping off the support table 4 or the crucible rolling speed being too fast due to too small friction, a graphite soft felt is laid above each support table 4.
Specifically, in the present embodiment, the material of the support table 4 is not limited, and may be, for example, a high-temperature resistant material such as graphite or ceramic.
As an embodiment, the driving assembly further comprises a first baffle 5 and a second baffle 6, the first baffle 5 and the second baffle 6 are higher than each support table 4, and the first baffle 5 and the second baffle 6 are respectively arranged at two opposite sides of the rolling area along the rolling direction of the crucible. Set up first baffle 5 and second baffle 6 respectively through the relative both sides in the roll district, and the height of first baffle 5 and second baffle 6 all is higher than the height of every brace table 4 to provide the power of blockking when rolling to the both ends in roll district for the crucible, prevent that the crucible from rolling from the roll district.
Specifically, in this embodiment, the material of the first baffle 5 and the second baffle 6 is not limited, and may be, for example, a high temperature resistant material such as graphite and ceramic.
As an embodiment, the heights of the first and second baffles 5 and 6 can be adjusted in order to accommodate crucibles of different diameters.
As an embodiment, a screw 7 is connected below each support platform 4, the driving assembly further comprises a support frame 8, a plurality of screw openings 9 are arranged on the support frame 8, and each screw opening 9 is matched with the corresponding screw 7 to enable the support platform 4 to ascend or descend. All be connected with screw rod 7 through the below that sets up every brace table 4 to mutually support with screw thread mouth 9 on the support frame 8, realize brace table 4's stable lift.
It will be appreciated that a power plant 10 and a computer control system 11 are also provided for controlling the elevation of each support table 4. The plurality of support tables 4 may share one power unit 10, or may use one power unit 10. The power device 10 is used for driving the screw 7 to rotate so as to drive the supporting platform 4 to lift; the computer control system 11 is used for controlling the height and speed of the lifting of the support bases 4, so that the plurality of support bases 4 form a rolling area with gradient. The connection mode between the power device 10 and the support 4 and the computer control system 11 may be the conventional one, and will not be described herein.
Specifically, all be connected with screw rod 7 below first baffle 5 and second baffle 6, be provided with screw thread mouth 9 on the support frame 8 to cooperate with screw rod 7 with first baffle 5 and second baffle 6 below, thereby drive the lift of first baffle 5 and second baffle 6.
In one embodiment, the length of the rolling zone is 2n π r +2r, where n is an integer not zero and r is the radius of the crucible. Through setting up the length in roll district, when making the crucible roll to the other end from the one end in roll district, accomplish the long crystal of crucible lateral wall whole circle to make the different position thickness of the polycrystal piece 3 of crucible lateral wall more even, and then guarantee that follow-up gaseous phase that forms when as long brilliant raw materials is more even, be favorable to improving the single crystal quality of growing.
Specifically, the present embodiment does not limit the value of n, and the value of n is only an integer that is not zero. Preferably, n is 1 and the support 4 is seven.
As shown in fig. 3, as an embodiment, the crucible assembly comprises a porous graphite plate 12 and a charging barrel 13 which are positioned inside the crucible body 1, the charging barrel 13 is arranged between the porous graphite plate 12 and the bottom wall of the crucible, the opening of the charging barrel 13 is connected with one side of the porous graphite plate 12, and a cavity structure is formed between the charging barrel 13 and the porous graphite plate 12, and the cavity structure forms a charging part. A cavity structure is formed between the charging barrel 13 and the porous graphite plate 12, so that a containing space is provided for the powder 2; meanwhile, the pores of the porous graphite plate 12 are favorable for the transmission of silicon carbide gas phase, and the porous graphite plate 12 can be used as a carbon source supplement of the silicon carbide polycrystalline block 3.
Specifically, the charging barrel 13 is located at the center in the radial direction of the crucible, thereby ensuring the uniform thickness of the polycrystalline lumps 3 on the side wall of the crucible.
As an implementation mode, the crucible assembly further comprises a crucible cover and a pressing plate member 14, the side wall of the crucible is provided with a boss 15, the graphite plate is arranged between the pressing plate member 14 and the boss 15, when the crucible cover covers the crucible body 1, the crucible cover compresses the pressing plate member 14, and then the graphite plate is fixed between the pressing plate member 14 and the boss 15. Through setting up clamp plate spare 14 and boss 15, fix the graphite cake between clamp plate spare 14 and boss 15, prevent that porous graphite cake 12 from rocking to appear in the in-process of preparation polycrystal piece 3, and simple structure, the placing and taking out of porous graphite cake 12 of being convenient for.
Specifically, the shape of the platen member 14 is not limited in this embodiment, and may be a strip or a ring. Preferably, the platen member 14 is ring-shaped, and the outer diameter of the platen member 14 is the same as the inner diameter of the crucible body 1.
As an embodiment, the opening of the charging barrel 13 is provided with an internal thread, and the side of the graphite plate close to the bottom wall of the crucible body 1 is provided with a mounting ring provided with an external thread, and the internal thread and the external thread cooperate to connect the charging barrel 13 and the graphite plate. Through making charging bucket 13 pass through threaded structure with the collar and be connected, can strengthen the installation steadiness between charging bucket 13 and the graphite cake, and simple structure, convenient to detach charging bucket 13 accomplishes and feeds and get the material process.
As an embodiment, the ratio of the outer diameter of the charging barrel 13 to the inner diameter of the crucible is 0.5 to 0.7: 1; and/or
The ratio of the distance between the porous graphite plate 12 and the bottom wall of the crucible body 1 to the height of the crucible body 1 is 0.5-0.8: 1. By setting the ratio of the outer diameter of the charging barrel 13 to the inner diameter of the crucible, the charging barrel 13 can be ensured to contain enough powder 2, the load force of a graphite plate is reduced, the side wall of the crucible outside the charging barrel 13 can be used as a crystal growth part to grow the silicon carbide polycrystal 3, and the coverage area of the polycrystal 3 is increased; through setting up the distance between porous graphite board 12 and the 1 diapire of crucible body, and then control silicon carbide polycrystal piece 3's height, reserve the crucible lateral wall that does not cover polycrystal piece 3 of suitable area, provide supplementary carbon source for follow-up growth single crystal.
Preferably, the ratio of the outer diameter of the charging barrel 13 to the inner diameter of the crucible is 0.6: 1; and/or
The ratio of the distance between the porous graphite plate 12 and the bottom wall of the crucible body 1 to the height of the crucible body 1 is 0.67: 1.
Example 2 preparation of a crucible Assembly with polycrystalline ingot 3
Example 2 of the present application provides a method of preparing a crucible assembly having a polycrystalline block 3, which is implemented by the apparatus of example 1, comprising the steps of:
1) charging: placing the powder 2 in a charging part of a crucible body 1 in a heating furnace 16;
2) removing impurities: the heating furnace 16 was evacuated to a pressure of 10-10Introducing inert gas to 300-500 mbar below mbar, and repeating the process at least twice;
3) and (3) low-temperature transition stage: introducing inert gas such as argon into the heating furnace 16 to control the pressure in the heating furnace 16 at 100mbar, heating the heating furnace 16 to 1300-; during the period, each support table 4 descends, and the descending speeds of the plurality of support tables 4 from left to right are sequentially increased, so that the crucible main body 1 rolls from the left end to the right end of the rolling area;
4) pressure reduction and temperature rise transition stage: adjusting the pressure of the heating furnace 16 to 50mbar, and keeping the temperature in the heating furnace 16 higher than the sublimation temperature of the powder by 10-30 ℃ for 2 hours; during the period, each supporting platform 4 rises, and the rising speed of a plurality of supporting platforms 4 from right to left is reduced in sequence, so that the crucible main body 1 rolls from the right end to the left end of the rolling area, and then the height of the supporting platforms 4 is continuously adjusted, so that the crucible main body 1 rolls from the left end to the right end in the rolling area, and a reciprocating motion is completed;
5) and (3) a stable growth stage: adjusting the pressure of the heating furnace 16 until the pressure is 1mbar, and keeping the temperature of the heating furnace 16 40-70 ℃ higher than the sublimation temperature of the powder 2 for 10 hours;
when the crucible main body 1 rolls to the leftmost side of the rolling area, each support table 4 descends, and the descending speeds of the plurality of support tables 4 from left to right are sequentially increased, so that the crucible main body 1 rolls from the left side to the right side of the rolling area; when the crucible main body 1 rolls to the rightmost side of the rolling area, each supporting table 4 rises, and the rising speed of the plurality of supporting tables 4 from right to left is reduced in sequence, so that the crucible main body 1 rolls from the right side to the left side of the rolling area, and the reciprocating rolling of the crucible main body 1 is realized;
6) and resetting each supporting platform 4, introducing inert gas into the heating furnace 16 to normal pressure, cooling, and taking out the crucible main body to finish the preparation of the polycrystalline block 3.
The crucible assemblies 1# -7# and D1# were prepared according to the above procedure, and the mass ratio of the powder, the ratio of the distance between the porous graphite plate and the bottom wall of the crucible body to the height of the crucible body, the presence or absence of the low temperature transition stage, and the stable growth conditions of the crucible body 1 were changed, respectively, and the other conditions were the same as shown in table 1.
TABLE 1
Example 3 testing of polycrystalline blocks
TABLE 2
EXAMPLE 4 preparation of silicon carbide single crystal
The crucible assembly 2# -7# and the crucible assembly D1# prepared in example 2 and the crucible assembly D2# filled with powder (wherein the mass ratio of the carbon powder to the silicon powder is 3: 5) are used as crucibles for preparing single crystals, seed crystals are arranged on the inner wall of a crucible cover, and the single crystals 2# -7#, the single crystals D1# and the single crystals D2# are prepared by respectively adopting the existing crystal growth method in the existing crystal growth device, and the method comprises the following steps:
1) impurity removal and pressure maintaining stage: placing the assembled crucible into a cavity, and pumping the cavity to 10 deg.C by using a vacuum pump-6-10- 8mbar, and pressure maintaining for 1 hour to prevent air leakage of the cavity in the heating process;
2) and (3) a nucleation stage: filling inert gas Ar gas into the cavity, raising the pressure of the cavity to 300-400mbar, raising the temperature to 1600 ℃, and continuing for 4 hours;
3) and (3) growth stage: reducing the pressure in the furnace body to 30mbar, and stably growing for 60 hours at 2300 ℃;
4) a single crystal is obtained.
The obtained single crystal was characterized and tested for cold light source carbon inclusions, polytype, crystal weight, total thickness deviation and impurity concentration, and the test results are shown in table 3.
TABLE 3
As can be seen from tables 2 and 3, in the crucible assembly 3# having polycrystalline blocks prepared by the example of the present application, the polycrystalline blocks have uniform thickness, good bulk density, small total thickness deviation and low impurity concentration, and thus the prepared single crystal has no carbon inclusion, no polytype condition, uniform thickness and high crystal quality; the crucible component No. 2 is the condition that the ratio of the distance between the porous graphite plate and the bottom wall of the crucible body to the height of the crucible body is 1:1, and data show that the large-area polytype of the crystal appears because no crucible carbon source is supplemented, the crystal grows slowly because the material source is insufficient, and the single crystal impurity content is slightly more; the crucible assembly No. 4 is the condition that the ratio of the distance between the porous graphite plate and the bottom wall of the crucible body to the height of the crucible body is 0.3:1, and data shows that the growth rate of a polycrystalline block is high, the charging barrel is connected with a bottom crystal and the side wall of the charging barrel is close to the polycrystalline block in the actual process, so that the polycrystalline block is not easy to take out, meanwhile, the formed polycrystalline block has high impurity content, so that the stacking density is low, the content of crystal carbon particles is high when single crystal growth is carried out, the deviation of the total thickness is slightly large, and the impurity concentration is high; the crucible assembly 5# improves the rolling speed of the crucible, so that the atmosphere is disordered, the gradient of the temperature field in the crucible is small, and the sublimated material is not easy to crystallize on the side wall and the bottom wall of the crucible, so that the weight of the formed polycrystalline material block is not as expected, the weight of the crystal is not as expected, and the impurity content is slightly high; the crucible assembly No. 6 grows at a low temperature, so that the growth rate of a polycrystalline block is slow, the growth rate of subsequent crystals is slow, and other parameters are good in performance; the crucible assembly 7# changes the mass ratio of carbon powder to silicon powder, the sublimation point of Si is 1400 ℃, so that the raw material is insufficient in the subsequent growth process, the polycrystalline block is in a stagnation growth state, the formation of the polycrystalline block is not facilitated, the subsequent growth of single crystal is not facilitated, and meanwhile, due to the shortage of the material source, the impurity amount is increased, so that the impurity concentration is slightly high; the crucible assembly No. 8 can not be used for subsequent single crystal growth due to serious carbonization; the crucible body of the crucible assembly D1# does not roll in the preparation process, so that the prepared polycrystalline block has uneven thickness and large thickness deviation, the single crystal prepared from the polycrystalline block has unstable crystal form due to extremely unstable atmosphere, large-area polytype appears, and the particle size of carbon particles in the crystal is slightly larger, and the impurity concentration is increased; the crucible assembly D2# takes powder as a raw material for preparing single crystals, and the prepared single crystals have a plurality of carbon coatings, and appear multi-types at the early stage, poor crystal quality, slightly larger total thickness deviation and slightly higher impurity concentration.
In addition, XRD diffraction patterns of the single crystal 3# and the single crystal D2# are shown in fig. 4 and 5, respectively. As can be seen from the figure, the single crystal 3# grown using the polycrystalline block produced by the method of the present application as a starting material has a narrower half-peak width, i.e., higher crystal quality.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.
The above description is only an example of the present application and is not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.
Claims (10)
1. An apparatus for producing a crucible having a polycrystalline block, comprising a crucible assembly and a heating member for heating the crucible assembly,
the crucible assembly is located in a heating area formed by the heating member, and the heating member is capable of forming a high temperature area and a low temperature area,
the crucible assembly comprises a crucible body, the crucible body comprises a charging part and a crystal growth part, the charging part is located in the crucible body, the crystal growth part is located in the low-temperature region, the charging part is located in the crucible body, the crystal growth part comprises a bottom wall of the crucible body and at least part of a side wall of the crucible body, powder in the charging part is sublimated to the crystal growth part, and the powder is crystallized into a polycrystalline block in the crystal growth part;
the device also comprises a driving component, wherein the driving component is used for driving the crucible body to move so that at least part of the side wall of the crucible passes through the low-temperature zone.
2. The apparatus of claim 1, wherein the drive assembly comprises a rolling region having a slope such that the sidewall of the crucible rolls along the rolling region.
3. The apparatus of claim 2, wherein the drive assembly comprises a plurality of support tables that collectively form the rolling region, the support tables each having a height that is independently adjustable to provide a slope to the rolling region.
4. The apparatus according to claim 3, wherein the driving assembly further comprises a first baffle and a second baffle, the first baffle and the second baffle each have a height higher than a height of each of the support tables, and the first baffle and the second baffle are respectively disposed on opposite sides of the rolling area in a rolling direction of the crucible.
5. The apparatus for preparing a crucible having a polycrystalline block according to claim 3, wherein a screw is connected below each support table,
the driving assembly further comprises a supporting frame, a plurality of threaded openings are formed in the supporting frame, and each threaded opening is matched with the corresponding screw rod, so that the supporting table can ascend or descend.
6. The apparatus of claim 2, wherein the rolling region has a length of 2n pi r +2r, wherein n is an integer not equal to zero and r is a radius of the crucible.
7. The apparatus for preparing a crucible having a polycrystalline block according to any one of claims 1 to 6, wherein the crucible assembly comprises a porous graphite plate and a charging bucket inside the crucible body, the charging bucket being disposed between the porous graphite plate and the crucible bottom wall, an opening of the charging bucket being connected to one side of the porous graphite plate,
a cavity structure is formed between the charging barrel and the porous graphite plate, and the cavity structure forms the charging part.
8. The apparatus for preparing a crucible having a polycrystalline block according to claim 7, wherein the crucible assembly further comprises a crucible cover and a platen member, the crucible side wall is provided with a boss, the graphite plate is disposed between the platen member and the boss,
when the crucible cover covers the crucible body, the crucible cover compresses the pressing plate piece, and the graphite plate is fixed between the pressing plate piece and the boss.
9. The apparatus for preparing a crucible having a polycrystalline block according to claim 7, wherein the opening of the charging barrel is provided with an internal thread, the graphite plate is provided with a mounting ring on a side thereof adjacent to the bottom wall of the crucible body, the mounting ring is provided with an external thread, and the internal thread and the external thread cooperate to connect the charging barrel and the graphite plate.
10. The apparatus for producing a crucible having a polycrystalline block according to claim 7, wherein the ratio of the outer diameter of the charging barrel to the inner diameter of the crucible is 0.5 to 0.7: 1; and/or
The ratio of the distance between the porous graphite plate and the bottom wall of the crucible body to the height of the crucible body is 0.5-0.8: 1.
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