CN220079252U - Thermal field device for preparing silicon carbide crystal - Google Patents
Thermal field device for preparing silicon carbide crystal Download PDFInfo
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- CN220079252U CN220079252U CN202321298379.XU CN202321298379U CN220079252U CN 220079252 U CN220079252 U CN 220079252U CN 202321298379 U CN202321298379 U CN 202321298379U CN 220079252 U CN220079252 U CN 220079252U
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- crucible
- sic
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- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 title claims abstract description 74
- 229910010271 silicon carbide Inorganic materials 0.000 title claims abstract description 74
- 239000013078 crystal Substances 0.000 title claims abstract description 54
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 185
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 184
- 239000010439 graphite Substances 0.000 claims abstract description 184
- 235000012431 wafers Nutrition 0.000 claims abstract description 43
- 239000002657 fibrous material Substances 0.000 claims abstract description 4
- 238000009413 insulation Methods 0.000 claims description 11
- 239000010409 thin film Substances 0.000 claims 1
- 238000004321 preservation Methods 0.000 abstract description 22
- 238000002425 crystallisation Methods 0.000 abstract description 6
- 230000008025 crystallization Effects 0.000 abstract description 6
- 238000005260 corrosion Methods 0.000 abstract description 5
- 230000007797 corrosion Effects 0.000 abstract description 5
- 230000002035 prolonged effect Effects 0.000 abstract description 2
- 238000000034 method Methods 0.000 description 17
- 230000000694 effects Effects 0.000 description 4
- 238000010030 laminating Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000000859 sublimation Methods 0.000 description 3
- 230000008022 sublimation Effects 0.000 description 3
- 239000000835 fiber Substances 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 206010024796 Logorrhoea Diseases 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Landscapes
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
The utility model discloses a thermal field device for preparing silicon carbide crystals, which comprises a graphite barrel and a graphite crucible arranged in the graphite barrel, wherein a crucible cover is arranged at the opening of the graphite crucible, one side of the crucible cover, which is close to the graphite crucible, is provided with seed crystals, the graphite barrel comprises a barrel body and a graphite top cover arranged at the opening of the barrel body, one side of the graphite top cover, which is close to the graphite crucible, is provided with SiC broken wafers, and the outer side of the graphite barrel is wrapped with an insulating layer. According to the utility model, the graphite barrel and the graphite top cover are arranged outside the graphite crucible, graphite paper and SiC broken wafers are adhered on the graphite top cover, and the Si broken wafers provide a crystallization core for Si-rich atmosphere escaping from the graphite crucible, so that most of Si-rich atmosphere can be crystallized at the SiC broken wafers, the Si-rich atmosphere is prevented from entering a heat preservation thermal field of graphite fiber materials to react with the heat preservation thermal field, the heat preservation performance of the heat preservation thermal field is weakened due to corrosion of the heat preservation thermal field, and the service life of the heat preservation thermal field is prolonged.
Description
Technical Field
The utility model relates to the technical field of semiconductor manufacturing, in particular to a thermal field device of a silicon carbide crystal.
Background
The main current method for preparing silicon carbide crystals in the market is a Physical Vapor Transport (PVT) method, and the principle is that silicon carbide powder in a graphite crucible is heated to sublimate, the atmosphere rises and reaches the surface of a seed crystal with lower temperature to be recrystallized under the driving of a temperature gradient, so that the silicon carbide single crystal is obtained. Compared with other processes (high-temperature chemical vapor deposition method, liquid phase method), the method has the advantages of simple equipment process, relatively high crystallization quality, low cost and the like.
The PVT method for preparing the silicon carbide monocrystal is characterized in that the sublimation of raw materials does not conform to the stoichiometric ratio, and Si-rich atmosphere at the initial stage of sublimation can enter a reaction chamber to react with a thermal insulation thermal field, so that the thermal insulation thermal field is corroded, the thermal insulation performance of the thermal insulation thermal field is weakened, the crystal growth temperature is changed, and particularly the thermal insulation thermal field is corroded more seriously along with the increase of crystal growth heat and crystal growth time. The corrosion of the heat-insulating thermal field shortens the service life of the heat-insulating thermal field, increases the cost, and easily causes the phase change of crystals and the uncontrolled morphology of the crystals, such as the asymmetry of the thickness of the crystals, and reduces the yield of the ingot.
Disclosure of Invention
An object of the present utility model is to provide a thermal field device for preparing silicon carbide crystals to solve the problem of corrosion of a thermal field at a temperature maintained by a Si-rich atmosphere, and to extend thermal field stability and service life of the thermal field.
In order to achieve the above purpose, the utility model adopts the following technical scheme: the utility model provides a thermal field device for preparing carborundum crystal, is in including graphite bucket and setting graphite crucible in the graphite bucket, graphite crucible's opening part is provided with the crucible cover, the crucible cover is close to one side of graphite crucible is provided with the seed crystal, the graphite bucket includes staving and sets up the graphite top cap of staving opening part, the graphite top cap is close to one side of graphite crucible is provided with the garrulous wafer of SiC, the outside parcel of graphite bucket has the thermal field that keeps warm.
Preferably, a space exists between the graphite crucible and the side wall of the barrel body, and a space exists between the crucible cover and the graphite top cover.
As another preference, the distance between the crucible cover and the graphite top cover is between 50mm and 300 mm.
Further preferably, the graphite top cover is connected with the graphite barrel through threads.
Further, the SiC broken wafers are covered on the surface of the graphite top cover to form a round film layer, and the area size of the SiC broken wafers is 0.5cm 2 ～1.5cm 2 The thickness of the SiC broken wafers is between 0.2mm and 1mm, and the area of the SiC broken wafers accounts for 50-75% of the area of the graphite top cover.
Further, an anti-adhesion component is arranged between the SiC broken wafer and the graphite top cover.
Further, the anti-adhesion component is graphite paper, the size of the graphite paper is larger than that of the SiC broken wafers, so that the SiC broken wafers are prevented from being contacted with the graphite top cover, and the thickness of the graphite paper is 0.2mm-2mm.
Further, the thermal field includes upper heat preservation portion and lower heat preservation portion, lower heat preservation portion with the bottom surface of staving, side and the laminating of graphite top cap's side, upper heat preservation portion with the top surface laminating of graphite top cap, thereby make the staving with connect the gap between the graphite top cap by lower heat preservation portion parcel.
Further, the heat preservation thermal field is made of graphite fiber materials to form graphite felt.
Compared with the prior art, the utility model has the beneficial effects that:
according to the utility model, the graphite barrel and the graphite top cover are arranged outside the graphite crucible, graphite paper and SiC broken wafers are adhered on the graphite top cover, and the Si broken wafers provide a crystallization core for Si-rich atmosphere escaping from the graphite crucible, so that most of Si-rich atmosphere can be crystallized at the SiC broken wafers, the Si-rich atmosphere is prevented from entering a heat preservation thermal field of graphite fiber materials to react with the heat preservation thermal field, the heat preservation performance of the heat preservation thermal field is weakened due to corrosion of the heat preservation thermal field, the service life of the heat preservation thermal field is prolonged, the repeatability and the stability of the temperature field in the crystal growth production process are improved, and the effects of improving the yield of SiC crystal ingots and reducing the cost are further achieved. In addition, still be provided with anti-adhesion spare between SiC broken wafer and the graphite top cap, anti-adhesion spare is graphite paper generally, after SiC broken wafer department is full crystallization, with graphite paper get rid of change into new graphite paper that has SiC broken wafer, graphite top cap can reuse.
Drawings
FIG. 1 is a schematic cross-sectional view of a thermal field device of the present utility model;
fig. 2 is a schematic view of a graphite top cap of a thermal field device of the present utility model.
In the figure: 1. a thermal field is preserved; 2. graphite paper; 3. a graphite barrel; 31. a graphite top cover; 32. a tub body; 4. a crucible cover; 5. seed crystal; 6. a graphite crucible; 7. a silicon carbide source; 8. SiC crushed wafers.
Detailed Description
The present utility model will be further described with reference to the following specific embodiments, and it should be noted that, on the premise of no conflict, new embodiments may be formed by any combination of the embodiments or technical features described below.
In the description of the present utility model, it should be noted that, for the azimuth words such as terms "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., the azimuth and positional relationships are based on the azimuth or positional relationships shown in the drawings, it is merely for convenience of describing the present utility model and simplifying the description, and it is not to be construed as limiting the specific scope of protection of the present utility model that the device or element referred to must have a specific azimuth configuration and operation.
It should be noted that the terms "first," "second," and the like in the description and in the claims are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order.
The terms "comprises" and "comprising," along with any variations thereof, in the description and claims, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Compared with other processes, the PVT method for preparing the silicon carbide crystal has the advantages of relatively simple equipment process, relatively high crystallization quality, low cost and the like, and the process principle is as follows: non-stoichiometric sublimation of the SiC powder source at high temperature (2200-2500 ℃) to obtain Si m C n Atmosphere of Si (1) m C n Because of the existence of the temperature gradient, the silicon carbide is diffused to the cold end seed crystal surface, when the growth interface substance of the seed crystal surface reaches a certain supersaturation degree, siC deposition growth occurs, and the most critical ring is the temperature gradient, and whether the temperature gradient is proper or not only determines the speed of the crystal growth rate, but also influences the height of the crystal quality (namely the yield of the ingot). The temperature gradient is mainly influenced by a heating mode and structure, a graphite part structure and a heat preservation thermal field, wherein the heat preservation thermal field is mainly a graphite felt made of high-temperature resistant graphite fibers, but the graphite felt is corroded due to the escape of Si-rich atmosphere, the heat preservation performance is reduced, the temperature gradient is changed, the phase change of crystals is easily caused, and the yield of the ingot is reduced.
In order to solve the above problems, the present utility model provides a thermal field apparatus for preparing silicon carbide crystals, which specifically comprises a graphite barrel 3 and a graphite crucible 6 disposed in the graphite barrel 3, the graphite crucible 6 being used for placing a silicon carbide source 7, the graphite crucibleThe opening part of the crucible 6 is provided with a crucible cover 4, one side of the crucible cover 4, which is close to the graphite crucible 6, is provided with a seed crystal placing area for placing seed crystals 5, the seed crystals 5 are SiC crystals with higher purity, the graphite barrel 3 comprises a barrel body 32 and a graphite top cover 31 arranged at the opening part of the barrel body 32, one side of the graphite top cover 31, which is close to the graphite crucible 6, is provided with a SiC broken wafer 8, the SiC broken wafer 8 is covered on a film layer which is circular on the surface of the graphite top cover 31, and the area size of the SiC broken wafer 8 is 0.5cm 2 ～1.5cm 2 The thickness of the SiC crushed wafers 8 is between 0.2mm and 1mm, the area of the SiC crushed wafers 8 accounts for 50 to 75 percent of the area of the graphite top cover 31, and the specific size parameters of the SiC crushed wafers can be correspondingly adjusted according to the weight of the grown crystal. The graphite crucible 6 and the graphite barrel 3 are arranged at intervals, that is, intervals exist between the graphite crucible 6 and the side wall of the barrel body 32, and intervals exist between the crucible cover 4 and the graphite top cover 31.
The outside parcel of graphite bucket 3 has thermal field 1 that keeps warm, in most embodiments, thermal field 1 is the graphite felt that graphite fibre made, graphite felt closely laminates in the outside of graphite bucket 3, graphite felt includes graphite felt and lower graphite felt, lower graphite felt laminating is in the bottom surface of staving 32, side and the side of graphite top cap 31, go up graphite felt laminating at the top of graphite top cap 31, go up graphite felt and the separation portion of graphite felt down at the top surface of graphite top cap 31 promptly, the side and the bottom surface of graphite bucket 3 are all wrapped up by graphite felt down, and then make the connection gap between graphite top cap 31 and the staving 32 can be wrapped up by graphite felt completely down, improve the heat preservation effect of graphite felt.
Specifically, when the PVT method is used for preparing the silicon carbide crystal, the silicon carbide source 7 placed in the graphite crucible 6 absorbs heat and sublimates to form a Si-rich atmosphere, the Si-rich atmosphere diffuses to a crystal face of a cold end of the crucible cover 4, the crystal is formed on the seed crystal 5 due to the existence of a temperature gradient, the non-crystallized Si-rich atmosphere can escape from the graphite crucible 6 into the graphite barrel 3, a crystal core is provided by the SiC broken wafer 8 adhered to the graphite top cover 31 at the top of the graphite barrel 3, and the Si-rich atmosphere escaping from the graphite crucible 6 can crystallize at the SiC broken wafer 8, so that the Si-rich atmosphere is prevented from escaping from between the barrel 32 and the graphite top cover 31 to enter the heat-preserving thermal field 1 to contact with the graphite felt and corrode the graphite felt. That is, the silicon carbide source 7 placed in the graphite crucible 6 absorbs heat to form a Si-rich atmosphere, and the Si-rich atmosphere is crystallized at the seed crystal 5 on the crucible cover 4 to form a silicon carbide crystal with higher purity, part of the non-crystallized Si-rich atmosphere escapes into the graphite barrel 3 at the SiC broken wafer 8 of the graphite top cover 31 to be secondarily crystallized to form a silicon carbide crystal with lower purity, so that most of the Si atmosphere is consumed, only a small part of the Si atmosphere is remained in the graphite barrel 3, the whole sealing effect of the graphite barrel 3 is improved through threaded connection between the graphite top cover 32 and the barrel 31, and corrosion of the heat-preserving thermal field 1 by the Si atmosphere can be avoided. It should be noted that, the crystals formed by the secondary crystallization can be removed from the graphite top cover 31 after the crystal growth is finished, and the crystals are re-crushed and then are re-input into the graphite crucible 6 as the silicon carbide source 7 for crystal growth, so that the crystal growth materials are recycled, resource waste is avoided, and production cost is reduced.
The connection can be dismantled through the screw thread between graphite top cap 31 and the staving 32 for be connected between graphite top cap 31 and the staving 32 more reliably, thereby solved originally just when the contact cooperation alone, because the problem that the dismouting wearing and tearing was repeated leads to the increase of connecting gap, thereby improved sealed effect, improved graphite barrel 3's life, prevented that external impurity from getting into in the graphite barrel 3, also can prevent the outside of the inside rich Si atmosphere of graphite barrel 3 to scatter, avoid outside graphite felt to be corroded. In addition, the graphite top cover 31 can be replaced by graphite top covers 31 with different sizes according to the sizes of the graphite crucible 6 and the graphite barrel 3, so as to adjust the distance between the graphite top cover 31 and the graphite crucible 6, preferably, the distance between the graphite crucible 6 and the graphite top cover 31 is between 50mm and 300mm, further, the temperature field in the graphite barrel 3 can be maintained in a proper range, most of Si atmosphere can be gathered at the graphite top cover 31, and the Si atmosphere can be crystallized at the SiC crushed wafers 8 on the graphite top cover 31, so that the Si-rich atmosphere is prevented from escaping and reacting with external graphite felt in a contact way.
In some preferred embodiments, an anti-sticking member is also provided between the SiC broken wafers 8 and the graphite top cover 31, for preventing SiC crystals from coming into contact with the graphite top cover 31 and preventing SiC crystals from sticking to the graphite top cover 31. The anti-blocking member is preferably a graphite paper 2, the thickness of the graphite paper 2 is between 0.2mm and 2mm, that is, the graphite paper 2 is disposed on the graphite top cover 31, the SiC broken wafers 8 are disposed on the graphite paper 2, and the size of the graphite paper 2 is larger than the size of the SiC broken wafers 8 so as to avoid the SiC broken wafers 8 from directly contacting the graphite top cover 31. When the Si-rich atmosphere is crystallized at the position of the SiC broken wafer 8, as gaps are formed between the SiC broken wafer 8 and the graphite top cover 31, the situation that the SiC crystal is adhered to the graphite top cover 31 easily occurs, the SiC crystal and the graphite top cover 31 can be effectively prevented by arranging the graphite paper 2, when the position of the SiC broken wafer 8 is fully crystallized, the SiC crystal is only required to be taken down from the graphite top cover 31 together with the graphite paper 2, the new graphite paper 2 and the SiC broken wafer 8 attached to the graphite paper 2 are replaced, the graphite top cover 31 can be reused while the SiC crystal is separated from the graphite top cover 31 conveniently, the graphite top cover 31 is prevented from being replaced due to the adhesion of the SiC crystal and the graphite top cover 31, and the production cost is reduced.
The foregoing has outlined the basic principles, features, and advantages of the present utility model. It will be understood by those skilled in the art that the present utility model is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present utility model, and various changes and modifications may be made therein without departing from the spirit and scope of the utility model, which is defined by the appended claims. The scope of the utility model is defined by the appended claims and equivalents thereof.
Claims (9)
1. The thermal field device for preparing the silicon carbide crystal is characterized by comprising a graphite barrel and a graphite crucible arranged in the graphite barrel, wherein a crucible cover is arranged at an opening of the graphite crucible, one side, close to the graphite crucible, of the crucible cover is provided with seed crystals, the graphite barrel comprises a barrel body and a graphite top cover arranged at the opening of the barrel body, one side, close to the graphite crucible, of the graphite top cover is provided with SiC broken wafers, and the outside of the graphite barrel is wrapped with a thermal insulation thermal field.
2. The thermal field apparatus of claim 1, wherein a space exists between the graphite crucible and the sidewall of the barrel, and a space exists between the crucible cover and the graphite top cover.
3. The thermal field apparatus of claim 2, wherein a distance between the crucible cover and the graphite top cover is between 50mm and 300 mm.
4. The thermal field apparatus of claim 1, wherein the graphite top cover is threadably connected to the graphite barrel.
5. The thermal field device of claim 1, wherein said SiC chip is covered on the surface of said graphite cap in a circular thin film layer, and the area size of said SiC chip is between 0.5cm 2 ～1.5cm 2 The thickness of the SiC broken wafers is between 0.2mm and 1mm, and the area of the SiC broken wafers accounts for 50-75% of the area of the graphite top cover.
6. The thermal field device of claim 1, wherein an anti-adhesion member is further disposed between the SiC crushed wafers and the graphite top cover.
7. The thermal field device of claim 6, wherein the anti-adhesion member is graphite paper having a size larger than the size of the SiC broken wafers to avoid contact between the SiC broken wafers and the graphite top cover, and the graphite paper has a thickness of 0.2mm to 2mm.
8. The thermal field apparatus of claim 1, wherein the thermal field comprises an upper thermal insulation portion and a lower thermal insulation portion, the lower thermal insulation portion being attached to the bottom surface, the side surface, and the side surface of the tub body and the graphite top cover, the upper thermal insulation portion being attached to the top surface of the graphite top cover such that a connection gap between the tub body and the graphite top cover is surrounded by the lower thermal insulation portion.
9. The thermal field apparatus according to any one of claims 1-8, wherein the thermal field is formed from graphite fiber material as a graphite felt.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321298379.XU CN220079252U (en) | 2023-05-24 | 2023-05-24 | Thermal field device for preparing silicon carbide crystal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321298379.XU CN220079252U (en) | 2023-05-24 | 2023-05-24 | Thermal field device for preparing silicon carbide crystal |
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| Publication Number | Publication Date |
|---|---|
| CN220079252U true CN220079252U (en) | 2023-11-24 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202321298379.XU Active CN220079252U (en) | 2023-05-24 | 2023-05-24 | Thermal field device for preparing silicon carbide crystal |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN220079252U (en) |
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2023
- 2023-05-24 CN CN202321298379.XU patent/CN220079252U/en active Active
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