CN116695258A - Annealing device and annealing method for silicon carbide single crystal - Google Patents
Annealing device and annealing method for silicon carbide single crystal Download PDFInfo
- Publication number
- CN116695258A CN116695258A CN202310980904.4A CN202310980904A CN116695258A CN 116695258 A CN116695258 A CN 116695258A CN 202310980904 A CN202310980904 A CN 202310980904A CN 116695258 A CN116695258 A CN 116695258A
- Authority
- CN
- China
- Prior art keywords
- annealing
- box
- silicon carbide
- crystal
- single crystal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000013078 crystal Substances 0.000 title claims abstract description 391
- 238000000137 annealing Methods 0.000 title claims abstract description 341
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 title claims abstract description 252
- 229910010271 silicon carbide Inorganic materials 0.000 title claims abstract description 180
- 238000000034 method Methods 0.000 title claims abstract description 43
- 239000000463 material Substances 0.000 claims abstract description 47
- 239000003575 carbonaceous material Substances 0.000 claims abstract description 16
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 38
- 229910002804 graphite Inorganic materials 0.000 claims description 37
- 239000010439 graphite Substances 0.000 claims description 37
- 239000011261 inert gas Substances 0.000 claims description 26
- 238000001816 cooling Methods 0.000 claims description 24
- 238000010438 heat treatment Methods 0.000 claims description 15
- 230000004308 accommodation Effects 0.000 claims description 10
- 238000007789 sealing Methods 0.000 claims description 6
- 238000011049 filling Methods 0.000 claims description 5
- 239000000843 powder Substances 0.000 claims 1
- 238000000859 sublimation Methods 0.000 abstract description 28
- 230000008022 sublimation Effects 0.000 abstract description 28
- 238000001212 derivatisation Methods 0.000 abstract description 2
- 239000007789 gas Substances 0.000 description 26
- 230000002829 reductive effect Effects 0.000 description 17
- 230000009286 beneficial effect Effects 0.000 description 9
- 230000002401 inhibitory effect Effects 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 8
- 238000002425 crystallisation Methods 0.000 description 8
- 230000008025 crystallization Effects 0.000 description 8
- 230000007547 defect Effects 0.000 description 8
- 239000011148 porous material Substances 0.000 description 5
- 238000001514 detection method Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000002349 favourable effect Effects 0.000 description 3
- 230000001737 promoting effect Effects 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 238000005054 agglomeration Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000011534 incubation Methods 0.000 description 2
- 238000004321 preservation Methods 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure
- C30B33/02—Heat treatment
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/10—Inorganic compounds or compositions
- C30B29/36—Carbides
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Inorganic Chemistry (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
The invention relates to the technical field of derivatization of silicon carbide crystal growth, in particular to an annealing device and an annealing method of a silicon carbide single crystal. The annealing device comprises: the crystal box comprises a first bottom plate, a first annular side plate and a crystal box upper cover, wherein the first bottom plate and the first annular side plate surround to form a crystal box cavity, the crystal box cavity is a silicon carbide single crystal containing part, and holes are uniformly formed in the axial middle position of the first annular side plate along the circumferential direction; the annealing box of porous carbon material, annealing box include second bottom plate, second annular curb plate and annealing box upper cover, and second bottom plate and second annular curb plate are around constituting annealing box cavity, and annealing box cavity includes crystal box and holds the cavity and the silicon carbide powder material holds the cavity, the silicon carbide powder hold the cavity wrap up in crystal box hold around the cavity. The annealing device can effectively inhibit sublimation of the silicon carbide crystal, reduce dislocation density of the silicon carbide crystal and improve crystal quality in the annealing process.
Description
Technical Field
The invention relates to the technical field of derivatization of silicon carbide crystal growth, in particular to an annealing device and an annealing method of a silicon carbide single crystal.
Background
Silicon carbide has the excellent properties of large forbidden bandwidth, high electron saturation drift rate, high critical breakdown field strength, high thermal conductivity, high chemical stability, radiation resistance and the like, and the excellent chemical and physical properties enable the silicon carbide material to have wide application scenes in the aspects of high temperature, high frequency, high power, radiation resistance, corrosion resistance devices, photoelectric integrated devices and the like.
Physical Vapor Transport (PVT) is the main method for industrially producing silicon carbide single crystals at present, and specifically, the gas generated by sublimation and decomposition of a silicon carbide raw material is transported to the surface of a seed crystal for recrystallization, so that the silicon carbide single crystals with larger area are obtained. In the growth process of silicon carbide single crystals, in order to enlarge the size of the single crystals, improve the quality of the single crystals and reduce crystal defects, a crystal growth surface is usually slightly convex, so that the growth rate of a central area is larger than that of an edge area, the axial temperature gradient of the central area is larger than that of the edge area, the growth time and the growth rate of crystals on the same plane as that of a seed crystal are different, the stress inside the crystals is further increased, the crystals are easy to crack in the subsequent processing process, the stress inside the crystals is removed at present, and dislocation in the crystals can be reduced by mainly carrying out in-situ annealing in a growth furnace and secondary annealing in an annealing furnace. However, due to the higher secondary annealing temperature, sublimation of silicon carbide crystals occurs at high temperatures: siC(s) -Si (g) +C(s), a thicker sublimated layer is easy to form on the surface of the crystal, and slippage expansion of dislocation defects is caused. Some researches suggest that sublimation of silicon carbide crystals is reduced by balancing component pressure through silicon carbide powder, however, the effect of inhibiting sublimation of crystals and improving the quality of silicon carbide crystals still cannot meet the requirements.
Disclosure of Invention
The invention aims to overcome the defect that a thicker sublimated layer is formed on the surface of a silicon carbide crystal and the dislocation density of the annealed crystal is still higher when the silicon carbide single crystal is annealed in an annealing furnace for the second time in the prior art, and provides an annealing device and an annealing method for the silicon carbide single crystal.
In order to achieve the above object, in a first aspect, the present invention provides an annealing apparatus for a silicon carbide single crystal, the apparatus comprising:
the crystal box is made of porous carbon material and comprises a first bottom plate, a first annular side plate and a crystal box upper cover, wherein the first bottom plate and the first annular side plate surround to form a crystal box cavity, the crystal box cavity is a silicon carbide single crystal containing part, an opening is formed in the middle of the axial direction of the first annular side plate, and the opening is uniformly arranged along the circumferential direction of the first annular side plate;
the annealing box is a porous carbon material box, the annealing box comprises a second bottom plate, a second annular side plate and an annealing box upper cover, the second bottom plate and the second annular side plate surround to form an annealing box cavity, the annealing box cavity comprises a crystal box accommodating cavity and a silicon carbide powder accommodating cavity, and the silicon carbide powder accommodating cavity wraps the periphery of the crystal box accommodating cavity.
In some preferred embodiments, the diameter of the openings is 0.8 mm-1.2 mm, and the interval between the openings is 60mm-100mm.
In some preferred embodiments, the annealing cassette comprises a first annealing cassette comprising a second bottom plate, a second annular side plate, and an annealing cassette upper cover, and at least one second annealing cassette comprising a second bottom plate and a second annular side plate;
the first annealing box and the second annealing box and/or the second annealing boxes can be connected through a clamping structure.
In a second aspect, the present invention provides an annealing method of a silicon carbide single crystal using the annealing apparatus of the first aspect, the annealing method comprising: placing the silicon carbide single crystal to be annealed in a silicon carbide single crystal accommodating part of a crystal box, placing the crystal box in a crystal box accommodating cavity of an annealing box, filling silicon carbide powder material into the silicon carbide powder accommodating cavity of the annealing box, sealing the annealing box, placing the annealing box in an annealing furnace, vacuumizing the annealing furnace chamber, introducing inert gas into the annealing furnace chamber, heating in the inert gas atmosphere to enable the temperature of the annealing box to rise to a first preset temperature, preserving heat for a first preset time, and cooling to obtain the annealed silicon carbide single crystal.
In some preferred embodiments, the method further comprises: and respectively placing graphite paper layers at the bottom of the silicon carbide single crystal accommodating part, the upper part of the material body formed by the silicon carbide powder material and the lower part of the material body formed by the silicon carbide powder material.
More preferably, the thickness of the graphite paper layer at the bottom of the silicon carbide single crystal accommodation part is 0.5mm-2.0mm, the thickness of the graphite paper layer at the upper part of the material body composed of silicon carbide powder is 0.5mm-2.0mm, and the thickness of the graphite paper layer at the lower part of the material body composed of silicon carbide powder is 0.5mm-2.0mm.
In some preferred embodiments, the inert gas is introduced into the annealing furnace chamber until the pressure of the annealing furnace chamber reaches 35kpa to 45kpa.
In some preferred embodiments, the first preset temperature is 1700 ℃ to 2100 ℃, and the first preset time is 6 hours to 8 hours.
In some preferred embodiments, the heating rate is 1.5 ℃/min to 2.5 ℃/min.
In some preferred embodiments, the cooling includes reducing the temperature of the annealing box from a first preset temperature to 1200 ℃ to 1400 ℃ at a first preset cooling rate, the first preset cooling rate being 0.7 ℃/min to 1.3 ℃/min.
According to the annealing device, the open holes uniformly arranged along the circumferential direction of the first annular side plate are arranged at the middle position of the axial direction of the first annular side plate of the crystal box. During annealing operation, the silicon carbide single crystal to be annealed is placed in the silicon carbide single crystal accommodating part of the crystal box, the crystal box filled with the silicon carbide single crystal to be annealed is placed in the crystal box accommodating cavity of the annealing box, silicon carbide powder is filled in the silicon carbide powder accommodating cavity around the crystal box, the temperature is raised to the annealing temperature, most of gas generated by sublimation of the silicon carbide powder filled outside the crystal box enters the crystal box through the opening on the first annular side plate, so that the driving force of diffusion of sublimation gas inside the crystal box from the axial middle part to the axial two ends can be improved, the sublimation gas is distributed more uniformly around the silicon carbide single crystal, the component pressure can be balanced uniformly, sublimation of the silicon carbide single crystal can be effectively inhibited while the crystal stress is removed sufficiently, the dislocation density of the silicon carbide single crystal is remarkably reduced, and the crystal quality is improved.
The annealing method provided by the invention can obviously reduce the dislocation density of the silicon carbide single crystal, thereby improving the crystal quality.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic structural view of an annealing apparatus for a silicon carbide single crystal according to the present invention.
FIG. 2 is a graph showing dislocation density before annealing of a silicon carbide single crystal according to example 1 of the present invention.
FIG. 3 is a graph showing dislocation density after annealing of a silicon carbide single crystal according to example 1 of the present invention.
FIG. 4 is a graph showing dislocation density before annealing of a silicon carbide single crystal according to example 2 of the present invention.
FIG. 5 is a graph showing dislocation density after annealing of a silicon carbide single crystal according to example 2 of the present invention.
FIG. 6 is a graph showing dislocation density before annealing a silicon carbide single crystal according to example 5 of the present invention.
FIG. 7 is a graph showing dislocation density after annealing of a silicon carbide single crystal according to example 5 of the present invention.
FIG. 8 is a graph showing dislocation density before annealing a silicon carbide single crystal according to example 6 of the present invention.
FIG. 9 is a graph showing dislocation density after annealing of a silicon carbide single crystal according to example 6 of the present invention.
FIG. 10 is a graph showing dislocation density before annealing a silicon carbide single crystal according to example 13 of the present invention.
FIG. 11 is a graph showing dislocation density after annealing of a silicon carbide single crystal according to example 13 of the present invention.
FIG. 12 is a graph showing dislocation density before annealing a silicon carbide single crystal according to comparative example 1 of the present invention.
FIG. 13 is a graph showing dislocation density after annealing of a silicon carbide single crystal according to comparative example 1 of the present invention.
Description of the reference numerals
1-a crystal box; 101-a first bottom plate; 102-a first annular side plate; 1021-punching; 103-crystal box upper cover; 104-crystal box cavity; 2-annealing box; 201-a second floor; 202-a second annular side plate; 203-an annealing box upper cover; 204-silicon carbide powder containment cavity.
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
The inventor of the invention researches and discovers that when a silicon carbide single crystal grown by a physical gas phase transport method is annealed for the second time in an annealing furnace, a thicker sublimated layer is easy to form on the surface of the silicon carbide crystal, the effect of reducing the dislocation density of the crystal is not ideal, the crystal quality is affected, and even though the component pressure is balanced by the silicon carbide powder, the sublimation of the silicon carbide single crystal is difficult to sufficiently inhibit, and the crystal quality cannot be ensured.
In this regard, in a first aspect, the present invention provides an annealing apparatus for a silicon carbide single crystal, the annealing apparatus including:
the crystal box 1, wherein the crystal box 1 is a porous carbon material box, the crystal box 1 comprises a first bottom plate 101, a first annular side plate 102 and a crystal box upper cover 103, the first bottom plate 101 and the first annular side plate 102 form a crystal box cavity 104 in a surrounding mode, the crystal box cavity 104 is a silicon carbide single crystal containing part, an opening 1021 is formed in the middle position of the first annular side plate 102 in the axial direction, and the opening 1021 is uniformly arranged along the circumferential direction of the first annular side plate 102;
The annealing box 2 is a porous carbon material box, the annealing box comprises a second bottom plate 201, a second annular side plate 202 and an annealing box upper cover 203, the second bottom plate 201 and the second annular side plate 202 surround to form an annealing box cavity, the annealing box cavity comprises a crystal box accommodating cavity and a silicon carbide powder accommodating cavity 204, and the silicon carbide powder accommodating cavity 204 is wrapped around the crystal box accommodating cavity.
According to the annealing device for the silicon carbide single crystal, before annealing, the silicon carbide single crystal to be annealed is placed in the silicon carbide single crystal accommodating part of the crystal box 1, the crystal box 1 filled with the silicon carbide single crystal to be annealed is placed in the crystal box accommodating cavity of the annealing box 2, silicon carbide powder accommodating cavity 204 wrapped around the crystal box 1 is filled with silicon carbide powder, in the annealing process, heat generated by the annealing furnace is conducted from outside to inside, silicon carbide powder is sublimated in advance, as the axial middle part of the first annular side plate 102 of the crystal box 1 is uniformly provided with the holes 1021 along the circumferential direction of the first annular side plate 102, most of gas generated by the pre-sublimation of the silicon carbide powder enters the crystal box 1 through the holes 1021, and driving force for diffusing sublimated gas from the axial middle part to the two ends is generated after entering the inside of the crystal box 1, so that the distribution of the sublimated gas around the silicon carbide single crystal is more uniform, the component pressure is balanced more uniformly, the crystal stress can be removed sufficiently, the sublimation of the silicon carbide single crystal is effectively inhibited, the dislocation density of the silicon carbide single crystal is remarkably reduced, and the quality of the silicon carbide single crystal is improved.
In addition, since the openings 1021 are uniformly formed in the axial middle of the first annular side plate 102 of the crystal box 1 along the circumferential direction of the first annular side plate 102, most of inert gas enters the crystal box 1 through the openings 1021 after being introduced into the annealing process, so that the inert gas is uniformly distributed around the silicon carbide single crystal, the inert gas can better play a role in protecting, and the crystallization atmosphere generated by the silicon carbide single crystal is effectively inhibited from forming polycrystal on the annealing box 2, the crystal box 1 and the crystal.
In the invention, the crystal box cavity 104 enclosed by the first bottom plate 101, the first annular side plate 102 and the crystal box upper cover 103 is a silicon carbide single crystal containing part, the annealing box cavity comprises a crystal box containing cavity and a silicon carbide powder containing cavity 204 wrapped around the crystal box containing cavity, before annealing, the crystal box 1 filled with the silicon carbide single crystal to be annealed is placed into the crystal box containing cavity of the annealing box 2, the silicon carbide powder is filled into the silicon carbide powder containing cavity 204 wrapped around the crystal box, the silicon carbide single crystal can be prevented from being directly contacted with the silicon carbide powder, and secondary sublimation of the crystal can be restrained in the annealing process.
It will be appreciated that the porous carbon material crystal box 1 and the porous carbon material annealing box 2 of the present invention have suitable porosities, so that on one hand, a small amount of sublimated gas and a small amount of inert gas of silicon carbide powder can uniformly enter the crystal box 1 through the pores of the crystal box 1, uniformity of gas phase inside the crystal box 1 is improved, unnecessary turbulence and the like formed by the gas phase inside is reduced, and on the other hand, inert gas uniformly enters the annealing box 2 through the pores of the annealing box 2, so that the inert gas can uniformly enter the crystal box 1 from the annealing box 2 through the pores of the crystal box 1.
In some preferred embodiments, the diameter of the openings 1021 is 0.8 mm-1.2 mm, and the intervals between the openings 1021 are 60mm-100mm. Under the preferred scheme, through adjusting the diameter and the interval of the opening 1021, more sublimation gas and inert gas of silicon carbide powder enter the crystal box 1 through the opening 1021, thereby being more beneficial to uniformly distributing the sublimation gas and the inert gas around the silicon carbide single crystal, being more beneficial to inhibiting the sublimation of the silicon carbide single crystal, reducing the dislocation density of the silicon carbide single crystal, inhibiting the crystallization atmosphere generated by the silicon carbide single crystal from forming polycrystal on the annealing box 2, the crystal box 1 and the crystal, and improving the quality of the silicon carbide single crystal. The diameter of the opening is controlled to be not less than 0.8mm, gas generated by sublimation of silicon carbide powder filled outside the crystal box 1 and inert gas mostly enter the crystal box 1 through the opening 1021 on the first annular side plate 102, the opening 1021 is not easy to block, thereby inhibiting sublimation of silicon carbide single crystals, increasing the reduction range of dislocation density of the silicon carbide single crystals in the annealing process, inhibiting crystallization atmosphere generated by the silicon carbide single crystals from forming polycrystal on the annealing box 2, the crystal box 1 and the crystal, the diameter of the opening is not more than 1.2mm, carbon-containing ash generated by the silicon carbide powder and the porous carbon material annealing box at high temperature is more favorably blocked from entering the crystal box, the interval of the opening 1021 is 60mm-100mm, gas balanced input is more favorably realized, thereby inhibiting sublimation of the silicon carbide single crystals, increasing the reduction range of dislocation density, and more favorably inhibiting crystallization atmosphere generated by the silicon carbide single crystals from forming polycrystal on the annealing box 2, the crystal box 1 and the crystal. The aperture diameters in the present invention may be specifically, for example, 0.8mm, 0.9mm, 1mm, 1.1mm and 1.2mm, and the aperture intervals may be specifically, for example, 60mm, 70mm, 80mm, 90mm and 100mm.
In some preferred embodiments, the annealing cassette 2 comprises a first annealing cassette comprising a second bottom plate 201, a second annular side plate 202, and an annealing cassette upper cover 203, and at least one second annealing cassette comprising a second bottom plate 201 and a second annular side plate 202; the first annealing box and the second annealing box and/or the second annealing boxes can be connected through a clamping structure. In the preferred scheme, during annealing operation, a first annealing box with an annealing box upper cover 203 and one or more second annealing boxes without the annealing box upper cover 203 can be connected through a clamping structure on the annealing box, wherein the first annealing box is positioned above the second annealing box, and a plurality of annealing boxes are placed in the same temperature zone of an annealing furnace, so that a plurality of crystals can be annealed simultaneously, and the annealing efficiency can be improved. The first annealing box is connected with the second annealing box and/or a plurality of second annealing boxes through a clamping structure, specifically, clamping grooves are formed in the lower edges of the first annealing box and the second annealing box, clamping hooks are arranged in the upper edges of the second annealing boxes, and the clamping grooves are in interference fit with the clamping hooks. The first annealing cassette of the present invention includes an annealing cassette upper cover 201 that further enables the silicon carbide crystal blocks in the plurality of crystal cassettes 1 to be at substantially uniform annealing temperatures.
In some preferred embodiments, the first annular side plate 102 is integrally connected to the first bottom plate 101, and the second annular side plate 202 is integrally connected to the second bottom plate 201.
In a second aspect, the present invention provides an annealing method of a silicon carbide single crystal using the annealing apparatus of the first aspect, the method comprising:
placing a silicon carbide single crystal to be annealed in a silicon carbide single crystal accommodating part of a crystal box 1, placing the crystal box 1 in a crystal box accommodating cavity of an annealing box 2, filling silicon carbide powder into a silicon carbide powder accommodating cavity 204 of the annealing box 2, sealing the annealing box 2, placing in an annealing furnace, vacuumizing an annealing furnace chamber, introducing inert gas into the annealing furnace chamber, heating under the inert gas atmosphere to enable the temperature of the annealing box 2 to rise to a first preset temperature, preserving heat for a first preset time, and cooling to obtain the annealed silicon carbide single crystal.
In the present invention, the temperature of the annealing cassette 2 is raised to a first preset temperature, so that the temperatures of the second bottom plate 201 and the upper cover 203 of the annealing cassette 2 are both raised to the first preset temperature.
In the annealing method, the silicon carbide single crystal to be annealed is placed in a crystal box 1 with openings 1021 uniformly arranged in the axial middle part along the circumferential direction, the crystal box 1 is placed in a crystal box accommodating cavity of an annealing box 2, silicon carbide powder is filled in a silicon carbide powder accommodating cavity 204 which wraps the crystal box accommodating cavity in the annealing box 2, in the process of heating the annealing box under inert gas atmosphere, the silicon carbide powder is sublimated in advance due to being surrounded on the outer side of the silicon carbide single crystal, most of the sublimated gas enters the crystal box 1 through the openings 1021 due to the arrangement of the openings 1021, A small part of pre-sublimated gas enters the crystal box 1 through the holes of the porous carbon material crystal box 1, and as more sublimated gas enters the crystal box 1 through the holes 1021, the driving force of the sublimated gas diffusing from the axial middle part to the axial two ends of the crystal box 1 is generated, so that the sublimated gas is distributed more uniformly around the silicon carbide single crystal, the component pressure is more uniformly balanced, the sublimation of the silicon carbide single crystal is effectively inhibited, the reduction range of the dislocation density of the silicon carbide single crystal in the annealing process is increased, and the quality of the silicon carbide single crystal is improved. In addition, during the annealing process, most of inert shielding gas also enters the crystal box 1 through the opening 1021, so that the inert shielding gas is distributed more uniformly around the silicon carbide single crystal, and the formation of polycrystal of the silicon carbide single crystal forming crystallization atmosphere on the annealing box 2, the crystal box 1 and the crystal can be more inhibited.
In some preferred embodiments, a plurality of silicon carbide single crystal blocks to be annealed are respectively placed in silicon carbide single crystal accommodation parts in a plurality of crystal boxes 1, a plurality of crystal boxes 1 filled with the silicon carbide single crystal blocks are respectively placed in a first annealing box and a second annealing box, silicon carbide powder material is filled in silicon carbide powder accommodation cavities 204 of the first annealing box and the second annealing box, the first annealing box and the second annealing boxes are connected through a clamping structure on an annealing box 2 from top to bottom, after the connection, the annealing boxes 2 are placed in the same temperature zone of an annealing furnace, so that a minimum temperature difference (0 ℃ -5 ℃) exists between each annealing box, then the vacuumizing treatment is carried out, and inert gas is introduced for heating and cooling. Under the preferred scheme, a plurality of crystals can be annealed simultaneously, and the annealing efficiency can be improved.
In some preferred embodiments, the method further comprises: and respectively placing graphite paper layers at the bottom of the silicon carbide single crystal accommodating part, the upper part of the material body formed by the silicon carbide powder material and the lower part of the material body formed by the silicon carbide powder material. Under the preferred scheme, a graphite paper layer is placed at the bottom of the silicon carbide single crystal accommodating part, and the silicon carbide single crystal to be annealed is positioned on the graphite paper layer, so that on one hand, the temperature conduction in the radial direction of the silicon carbide single crystal is promoted, and the temperature distribution in the radial direction is more uniform; on the other hand, the heating of the annealing furnace is conducted radially from outside to inside, a heating source is not arranged axially, and the graphite paper layer can block a part of axial temperature conduction, so that the crystal is more favorably in a proper temperature range; thereby better improving the stress distribution in the crystal, reducing the dislocation density and improving the crystal quality. On the one hand, the airtightness of the top and the bottom and the side parts of the annealing box 2 can be distinguished, the introduced inert gas is more beneficial to entering the annealing box 2 from the side surface, then enters the crystal box 1 from the opening 1021, the effect that the inert protective gas inhibits the crystallization atmosphere generated by the silicon carbide single crystal from forming polycrystal on the annealing box 2, the crystal box 1 and the crystal is better exerted, on the other hand, the temperature conduction in the radial direction of the silicon carbide powder material is better promoted, the temperature distribution in the radial direction is more uniform, meanwhile, a part of the axial temperature conduction is blocked, the silicon carbide powder material is more beneficial to being in a proper temperature interval, the sublimation of the silicon carbide crystal is inhibited through the balance component pressure of the silicon carbide powder material, and the reduction range of the dislocation density of the silicon carbide single crystal in the annealing process is increased; in addition, the temperature distribution of the silicon carbide powder material in the radial direction is more uniform, and the silicon carbide powder material is in a proper temperature range, so that the temperature distribution of the silicon carbide single crystal in the radial direction can be promoted to be more uniform, the temperature distribution in the proper temperature range is better improved, and the dislocation density is reduced.
In some preferred embodiments, the thickness of the graphite paper layer at the bottom of the silicon carbide single crystal accommodation part is 0.5mm-2.0mm, the thickness of the graphite paper layer at the upper part of the material body composed of the silicon carbide powder material is 0.5mm-2.0mm, and the thickness of the graphite paper layer at the lower part of the material body composed of the silicon carbide powder material is 0.5mm-2.0mm. Under the preferred scheme, the thickness of the graphite paper layer at the bottom of the silicon carbide single crystal containing part is controlled to be 0.5mm-2.0mm, so that the silicon carbide single crystal is more favorably in a proper temperature interval, and meanwhile, the thickness is not less than 0.5mm, and the radial temperature distribution of the silicon carbide single crystal is more favorably uniform, thereby better improving the stress distribution in the crystal, reducing the dislocation density and improving the crystal quality. The thickness of the graphite paper layer at the upper part of the material body formed by the silicon carbide powder material and the thickness of the graphite paper layer at the lower part of the material body formed by the silicon carbide powder material are both 0.5mm-2.0mm, which is more beneficial to enabling the silicon carbide powder material to be in a proper temperature interval, generating proper sublimation gas, effectively inhibiting sublimation of the silicon carbide single crystal, increasing the reduction range of dislocation density of the silicon carbide single crystal in an annealing process, promoting the silicon carbide single crystal to be in a proper temperature interval, better improving the stress distribution in the crystal, simultaneously, the thickness is not less than 0.5mm, being more beneficial to enabling inert gas to enter the annealing box 2 from the side surface, then entering the crystal box 1 from the open pore 1021, inhibiting the silicon carbide single crystal from generating crystallization atmosphere to form polycrystal on the annealing box 2, the crystal box 1 and the crystal, being more beneficial to enabling the temperature distribution of the silicon carbide powder material to be more uniform in the radial direction, promoting the silicon carbide powder material to be uniformly sublimated, increasing the reduction range of dislocation density of the silicon carbide single crystal in the annealing process, promoting the radial temperature distribution of the silicon carbide single crystal to be more uniform, and better improving the stress distribution in the crystal.
The thickness of the graphite paper layer at the bottom of the silicon carbide single crystal accommodation portion in the present invention may be, for example, specifically 0.5mm, 1.0mm, 1.5mm and 2.0mm, the thickness of the graphite paper layer at the upper part of the body of silicon carbide powder material may be, for example, specifically 0.5mm, 1.0mm, 1.5mm and 2.0mm, and the thickness of the graphite paper layer at the lower part of the body of silicon carbide powder material may be, for example, specifically 0.5mm, 1.0mm, 1.5mm and 2.0mm.
In some preferred embodiments, the inert gas is introduced into the annealing furnace chamber until the pressure of the annealing furnace chamber reaches 35kpa to 45kpa. Under the preferred scheme, the pressure of the annealing furnace chamber is controlled to be not lower than 35kPa, inert gas is more favorable for entering the annealing box through pores on the porous carbon material annealing box, most of inert gas enters the crystal box through openings in the axial middle part of the crystal box, the inert gas is rapidly and uniformly diffused from the axial middle part to the two ends of the axial direction, the silicon carbide single crystal is restrained from forming polycrystal in the annealing box, the crystal box and the crystal, in addition, the pressure of the annealing furnace chamber is controlled to be not lower than 35kPa, sublimation gas can be promoted to enter the crystal box through the openings, after entering the openings, the rapid diffusion from the axial middle part to the two ends of the axial direction is uniform, the component pressure is more uniformly balanced, the sublimation of the silicon carbide single crystal is more favorable for being restrained, the reduction range of dislocation density of the silicon carbide single crystal in the annealing process is increased, the quality of the silicon carbide single crystal is improved, the pressure of the annealing furnace chamber is controlled to be not higher than 45kPa, the sublimation quantity of silicon carbide powder is more favorable for being controlled, enough sublimation gas enters the crystal box, the component pressure is balanced, the sublimation of the silicon carbide single crystal is restrained from sublimating, and the dislocation density of the silicon carbide single crystal is reduced.
Preferably, the annealing furnace chamber is vacuumized until the pressure of the annealing furnace chamber is lower than 100pa, and then inert gas is introduced into the annealing furnace chamber until the pressure of the annealing furnace chamber is 35 kPa-45 kPa.
In some preferred embodiments, the first preset temperature is 1700 ℃ to 2100 ℃, and the first preset time is 6 hours to 8 hours. Under the preferred scheme, the annealing temperature is not lower than 1700 ℃, the sufficient stress release is more facilitated, the dislocation density of crystals is reduced, the annealing temperature is not higher than 2100 ℃, the generation of polycrystal is more facilitated to be avoided, the silicon carbide powder is prevented from caking due to the quasi-long crystalline state, the heat preservation time is not lower than 6 hours, the stress release and the removal of defects such as dislocation are more facilitated, the heat preservation time is not higher than 8 hours, the generation of polycrystal is more facilitated to be avoided, and the agglomeration of the silicon carbide powder due to the quasi-long crystalline state is avoided. The first preset temperature of the present invention may be, for example, 1700 ℃, 1800 ℃, 1900 ℃, 2000 ℃, and 2100 ℃ and the first preset time may be, for example, 6h, 6.5h, 7h, 7.5h, and 8h.
More preferably, the first preset temperature is 1900-2100 ℃, and the first preset time is 6-7 hours. Under the preferred scheme, the stress is more favorably released, defects such as dislocation and the like are removed, polycrystal is avoided, and the agglomeration of silicon carbide powder is prevented.
In some preferred embodiments, the heating is at a rate of 1.5 ℃/min to 2.5 ℃/min. Under the preferential condition, the heating rate of heating to the annealing temperature (first preset temperature) is controlled, so that the temperature inside the silicon carbide single crystal is more beneficial to slowly and uniformly rising, the temperature difference inside the silicon carbide single crystal is reduced, the stress is more beneficial to fully releasing due to the slowly and uniformly rising temperature, the defects such as dislocation are removed, new defects are avoided, and the crystal quality is improved.
In some preferred embodiments, the cooling includes reducing the temperature of the annealing box 2 from the first preset temperature to 1200 ℃ to 1400 ℃ at a first preset cooling rate of 0.7 ℃/min to 1.3 ℃/min. Under the preferred scheme, after the first preset temperature is kept warm, the temperature is controlled to be cooled to 1200-1400 ℃ at the cooling rate of 0.7-1.3 ℃/min, so that defects such as dislocation in crystals are removed, the dislocation density is reduced, compared with the method that the dislocation density is directly cooled along with a furnace after the first preset temperature, the cooling is controlled at a lower rate, the dislocation density is reduced, the temperature of an annealing box is controlled to be not lower than 1200 ℃, the first preset cooling rate is not lower than 0.7 ℃/min, the cooling efficiency is improved, the temperature of the annealing box is controlled to be not higher than 1400 ℃, the first preset cooling rate is not higher than 1.3 ℃/min, and the dislocation density is reduced. In the present invention, the temperature of the annealing cassette may be reduced from the first preset temperature to 1200 ℃, 1250 ℃, 1300 ℃, 1350 ℃ and 1400 ℃ at a first preset cooling rate, which may be 0.7 ℃/min, 0.8 ℃/min, 0.9 ℃/min, 1 ℃/min, 1.1 ℃/min, 1.2 ℃/min and 1.3 ℃/min.
The invention will be further described in detail with reference to specific examples.
The detection method involved in the examples is as follows: the dislocation density of the silicon carbide single crystal is detected by a dislocation detector after the slice is corroded. The detection method of stress release condition of annealed silicon carbide single crystal is polarized stress detector. The detection method of the annealing box, the crystal box and the polycrystal formed on the crystal is to observe by using a purple light lamp or a strong light flashlight. The results of detecting dislocation densities of the silicon carbide single crystals of examples 1, 2, 5, 6, 13 and comparative example 1 are shown in fig. 2 to 13, each of which includes 4 sub-graphs, the 4 sub-graphs respectively representing the results of detecting dislocation densities of the total dislocation (SUM), the Threading Screw Dislocation (TSD), the threading ductile dislocation (TED) and the basal vector surface dislocation (BPD), the numbers in the upper left corners of the 4 sub-graphs represent the numbers of the corresponding dislocations in the silicon carbide single crystal samples, the gray levels of the grids in the sub-graphs are different, the different gray levels represent the dislocation density levels of the grids, and the corresponding relationships between the gray levels and the dislocation density levels are shown in the legend in the lower right corner of each sub-graph.
Example 1
Referring to fig. 1, an annealing device for a silicon carbide single crystal of the present embodiment comprises a plurality of porous carbon material crystal boxes 1, each crystal box comprising a first bottom plate 101, a first annular side plate 102 and a crystal box upper cover 103, wherein the first bottom plate 101 and the first annular side plate 102 are integrally connected, the first bottom plate 101 and the first annular side plate 102 surround a crystal box cavity 104, the crystal box cavity 104 is a silicon carbide single crystal accommodating part, openings 1021 are uniformly arranged in the axial middle position of the first annular side plate 102 of each crystal box 1 along the circumferential direction, the diameter of the openings 1021 is 1mm, and the intervals of the openings are 80mm.
The annealing device further comprises a first porous carbon material annealing box and two second porous carbon material annealing boxes, the first annealing box is provided with a second bottom plate 201, a second annular side plate 202 and an annealing box upper cover 203, the second annealing box is provided with the second bottom plate 201 and the second annular side plate 202, the second bottom plate 201 and the second annular side plate 202 are integrally connected, the second bottom plate 201 and the second annular side plate 202 surround to form an annealing box cavity, and the annealing box cavity comprises a crystal box accommodating cavity in the middle part and a silicon carbide powder accommodating cavity 204 wrapping the periphery of the crystal box accommodating cavity; the upper edge of the second annular side plate 202 of the first annealing box is provided with a clamping hook, the edge of the upper cover 203 of the annealing box is provided with a clamping groove, the lower edges of the first annealing box and the two second annealing boxes are provided with clamping grooves, and the upper edges of the second annealing boxes are provided with clamping hooks which are in interference fit with the clamping hooks.
The annealing method comprises the following steps:
step one: the method comprises the steps of placing graphite paper layers with the thickness of 0.5mm at the bottoms of silicon carbide single crystal containing parts of 3 crystal boxes 1, placing 3 silicon carbide single crystal blocks to be annealed on the graphite paper layers of three crystal boxes 1 respectively, sealing each crystal box 1 by using a crystal box upper cover 103, placing graphite paper layers with the thickness of 1.0mm at the bottoms of a first annealing box and a second annealing box, placing each crystal box 1 containing the silicon carbide single crystal blocks to be annealed into a crystal box containing cavity of one first annealing box and two second annealing boxes respectively, filling silicon carbide powder containing cavities 204 around each crystal box 1 with silicon carbide powder, placing graphite paper layers with the thickness of 1.0mm at the upper part of a material body formed by the silicon carbide powder, connecting the annealing boxes 2 filled with the crystal boxes 1 and the silicon carbide powder by using clamping grooves and clamping hooks, wherein the first porous carbon material annealing box is located at the uppermost, and sealing the annealing boxes 2 by using the annealing box upper cover 203 of the first annealing box.
Step two: placing a plurality of annealing boxes 2 in the same temperature zone of an annealing furnace, vacuumizing the annealing furnace chamber until the pressure of the annealing furnace chamber is lower than 100pa, introducing argon into the annealing furnace chamber until the pressure of the annealing furnace chamber is 40kpa, heating the annealing boxes to 2000 ℃ at a heating rate of 1.5 ℃/min, preserving heat for 400min, cooling the annealing boxes to 1300 ℃ at a cooling rate of 1 ℃/min after preserving heat, and then cooling along with the furnace after power failure to obtain annealed silicon carbide single crystals.
From fig. 2 and 3, it can be seen that the total dislocation (SUM), threading ductile dislocation (TED), basal Plane Dislocation (BPD), and Threading Screw Dislocation (TSD) of the annealed silicon carbide single crystal are significantly reduced, and dislocation situation is significantly improved. The stress distribution of the silicon carbide single crystal is obviously improved and the stress of the silicon carbide single crystal is removed after annealing. After annealing, no polycrystal was formed on the annealing cassette, the crystal cassette and the crystal.
Example 2
Reference example 1 was made, except that the spacing of the openings was 50mm. From fig. 4 and 5, it can be seen that the dislocation conditions of the total dislocation (SUM), the threading ductile dislocation (TED), and the Basal Plane Dislocation (BPD) of the silicon carbide single crystal are significantly improved, and the number of Threading Screw Dislocations (TSD) is greatly increased, after annealing. After annealing, fewer polycrystal is formed on the annealing box, the crystal box and the crystal, and the annealing obviously removes the stress of the silicon carbide monocrystal.
Example 3
Reference example 1 was followed except that the diameter of the opening was 0.5mm. In this example, after annealing, the dislocation conditions of the total dislocation (SUM) and threading ductile dislocation (TED) of the silicon carbide single crystal were significantly improved, and the numbers of Threading Screw Dislocation (TSD) and Basal Plane Dislocation (BPD) were extremely increased. After annealing, fewer polycrystal is formed on the annealing box, the crystal box and the crystal, and the annealing obviously removes the stress of the silicon carbide monocrystal.
Example 4
Reference example 1 was made, except that the thickness of the graphite paper layer placed at the bottom of the silicon carbide single crystal accommodation portion was 2.5mm. In this example, after annealing, the dislocation conditions of the total dislocation (SUM) and Threading Screw Dislocation (TSD) of the silicon carbide single crystal were significantly improved, and the numbers of threading ductile dislocation (TED) and Basal Plane Dislocation (BPD) were extremely increased. Most of the stress in the silicon carbide single crystal is removed by annealing, and less stress is also present. After annealing, substantially no polycrystals are formed on the annealing cassette, the crystal cassette, and the crystal.
Example 5
With reference to example 1, a graphite paper layer having a thickness of 0.4mm was placed on the bottom of each of the first and second annealing boxes, and a graphite paper layer having a thickness of 0.4mm was placed on the upper portion of each of the bodies of silicon carbide powder. From fig. 6 and 7, after annealing, the dislocation conditions of the total dislocation (SUM) and the Basal Plane Dislocation (BPD) of the silicon carbide single crystal were significantly improved, and the dislocation conditions of the threading ductile dislocation (TED) and the Threading Screw Dislocation (TSD) were not greatly changed from those before annealing. Most of the stress in the silicon carbide single crystal is removed by annealing, and less stress is also present. Less polycrystal is formed on the annealing box, the crystal box and the crystal after annealing.
Example 6
Reference example 1 was made, except that no graphite paper layer was placed on the bottom of the silicon carbide single crystal accommodation portion. From fig. 8 and 9, it can be seen that, after annealing, the dislocation conditions of the total dislocation (SUM) and the threading ductile dislocation (TED) of the silicon carbide single crystal are significantly improved, the dislocation number of the Threading Screw Dislocation (TSD) is extremely increased, and the dislocation number of the basal vector surface dislocation (BPD) is relatively slightly increased. Most of the stress in the silicon carbide single crystal is removed by annealing, and a small amount of stress is also removed, so that no polycrystal is formed on the annealing box, the crystal box and the crystal after annealing.
Example 7
Reference example 1 was made, except that no graphite paper layer was placed at the bottom of the first and second annealing boxes. In this example, after annealing, the dislocation conditions of the total dislocation (SUM) and Basal Plane Dislocation (BPD) of the silicon carbide single crystal were significantly improved, and the numbers of threading ductile dislocation (TED) and Threading Screw Dislocation (TSD) were extremely increased. After annealing, a small amount of polycrystal is formed on the annealing box, the crystal box and the crystal, and most of stress and a small amount of stress in the silicon carbide single crystal are removed through annealing.
Example 8
Reference example 1 was made, except that no graphite paper layer was placed on top of the body of silicon carbide powder. In this example, after annealing, the dislocation conditions of the total dislocation (SUM) and Basal Plane Dislocation (BPD) of the silicon carbide single crystal were significantly improved, and the numbers of threading ductile dislocation (TED) and Threading Screw Dislocation (TSD) were extremely increased. After annealing, a small amount of polycrystal is formed on the annealing box, the crystal box and the crystal, and most of stress and a small amount of stress in the silicon carbide single crystal are removed through annealing.
Example 9
Reference example 1 was made, except that no graphite paper layer was placed on the bottom of the first and second annealing boxes and the upper part of the body of silicon carbide powder. In this example, after annealing, the dislocation conditions of the total dislocation (SUM) and Basal Plane Dislocation (BPD) of the silicon carbide single crystal were significantly improved, and the numbers of threading ductile dislocation (TED) and Threading Screw Dislocation (TSD) were slightly increased. Most of the stress in the silicon carbide single crystal is removed by annealing, and a small amount of stress is also removed. And forming a small amount of polycrystal on the annealing box, the crystal box and the crystal after annealing.
Example 10
The process was performed as in example 1, except that the annealing temperature was increased to 1700℃in the annealing furnace, and the annealing furnace was kept for 400 minutes and cooled. In this example, after annealing, the dislocation conditions of the total dislocation (SUM) and Threading Screw Dislocation (TSD) of the silicon carbide single crystal were significantly improved, and the numbers of threading ductile dislocation (TED) and Basal Plane Dislocation (BPD) were extremely increased. After annealing, no polycrystal is basically formed on the annealing box, the crystal box and the crystal, and most of stress in the silicon carbide single crystal is removed and less stress is generated after annealing.
Example 11
The process was performed as in example 1, except that the annealing temperature was increased to 1600℃and the annealing furnace was kept at that temperature for 400 minutes, and then cooled, unlike the annealing temperature in example 1. In this example, after annealing, the dislocation conditions of the total dislocation (SUM) and Threading Screw Dislocation (TSD) of the silicon carbide single crystal were significantly improved, and the numbers of threading ductile dislocation (TED) and Basal Plane Dislocation (BPD) were slightly increased. After annealing, no polycrystal is basically formed on the annealing box, the crystal box and the crystal, and most of stress and a small amount of stress in the silicon carbide single crystal are removed through annealing.
Example 12
The process was performed as in example 1, except that the temperature of the annealing furnace was raised to 2000℃at a heating rate of 3℃per minute, and the annealing furnace was kept for 400 minutes. In this example, after annealing, the dislocation conditions of the total dislocation (SUM) and threading ductile dislocation (TED) of the silicon carbide single crystal were significantly improved, and the numbers of Threading Screw Dislocation (TSD) and Basal Plane Dislocation (BPD) were extremely increased. After annealing, no polycrystal is basically formed on the annealing box, the crystal box and the crystal, and most of stress in the silicon carbide single crystal is removed and less stress is generated after annealing.
Example 13
With reference to example 1, except that the annealing furnace was cooled down to 1300 ℃ at a cooling rate of more than 2 ℃/min after the incubation, followed by furnace cooling after the power outage. From fig. 10 and 11, it can be seen that, after annealing, the dislocation conditions of the total dislocation (SUM) and Threading Screw Dislocation (TSD) of the silicon carbide single crystal are improved, and the numbers of threading ductile dislocation (TED) and Basal Plane Dislocation (BPD) are reduced slightly. After annealing, no polycrystal is basically formed on the annealing box, the crystal box and the crystal, and after annealing, the stress of the silicon carbide monocrystal is obviously removed.
Example 14
With reference to example 1, except that the temperature of the lehr was reduced to 1500 ℃ at a cooling rate of less than 1 ℃/min after incubation. In this example, after annealing, the dislocation conditions of the total dislocation (SUM) and Threading Screw Dislocation (TSD) of the silicon carbide single crystal are improved, the numbers of threading screw dislocation (TED) and Basal Plane Dislocation (BPD) are extremely increased, no polycrystal is formed on the annealing box, the crystal box and the crystal after annealing, and the stress of the silicon carbide single crystal is remarkably removed after annealing.
Comparative example 1
Reference is made to example 1 except that no opening is provided in the axial middle position of the first annular side plate of each crystal box. From fig. 12 and 13, after annealing, the dislocation conditions of the total dislocation (SUM) and the Threading Screw Dislocation (TSD) and the threading ductile dislocation (TED) of the silicon carbide single crystal are not improved, but rather the dislocation number is increased, wherein the total dislocation (SUM) and the Threading Screw Dislocation (TSD) are slightly increased, the number of the threading ductile dislocation (TED) is remarkably increased, the dislocation condition of the basal vector surface dislocation (BPD) is improved, more polycrystal is formed on the annealing box, the crystal box and the crystal after annealing, and the stress of the silicon carbide single crystal is remarkably removed after annealing.
Comparative example 2
With reference to embodiment 1, the annealing device is different in that the crystal box comprises a first crystal box and two second crystal boxes, the first crystal box is provided with a first bottom plate, a first annular side plate and a crystal box upper cover, the second crystal box is provided with a first bottom plate and a first annular side plate, the upper edge of the first annular side plate of the first crystal box is provided with a clamping hook, the edge of the crystal box upper cover is provided with a clamping groove, the lower edges of the first crystal box and the two second crystal boxes are provided with clamping grooves, the upper edge of the second crystal box is provided with a clamping hook, and the clamping groove is in interference fit with the clamping hook; only one annealing box is provided, the annealing box having a second bottom plate, a second annular side plate, and an annealing box upper cover.
The corresponding annealing method is characterized in that after 3 silicon carbide single crystal blocks to be annealed are respectively placed on graphite paper layers of three crystal boxes, the crystal boxes filled with the silicon carbide single crystal blocks are connected through clamping grooves and clamping hooks, wherein a first crystal box is positioned at the uppermost part, a crystal box upper cover of the first crystal box is used for sealing the crystal box, the graphite paper layers are placed at the bottom of the annealing box, the connected crystal boxes are placed in crystal box accommodating cavities of the annealing box, silicon carbide powder materials are used for filling silicon carbide powder material accommodating cavities around the connected crystal boxes, the graphite paper layers are placed at the upper parts of blocks formed by the silicon carbide powder materials, the annealing box is sealed through the annealing box upper cover, and the annealing box is placed in an annealing furnace.
In the comparative example, the dislocation conditions of the total dislocation (SUM), the Threading Screw Dislocation (TSD), the threading ductile dislocation (TED) and the Basal Plane Dislocation (BPD) of the silicon carbide single crystal are not obviously improved after annealing, polycrystal is basically not generated on an annealing box, a crystal box and a crystal after annealing, and the stress of the silicon carbide single crystal is obviously reduced after annealing.
It can be seen from comparative examples 1 to 14 and comparative examples 1 to 2 that the openings uniformly provided along the circumferential direction of the first annular side plate are provided at the axial middle position of the first annular side plate of the crystal box so that the diameters of the openings are 0.8mm to 1.2mm, the intervals of the openings are 60mm to 100mm, and graphite paper layers are respectively placed at the bottom of the silicon carbide single crystal accommodation portion, the upper portion of the material body composed of silicon carbide powder material and the lower portion of the material body composed of silicon carbide powder material so that the thickness of the graphite paper layers is 0.5mm to 2.0mm, the annealing temperature is 1700 ℃ to 2100 ℃, and after annealing, the cooling is controlled, so that dislocation conditions of silicon carbide crystals can be remarkably improved while crystal stress is sufficiently removed, and at the same time, the formation of polycrystal of the silicon carbide single crystal forming crystallization atmosphere on the annealing box, the crystal box and the crystal can be suppressed.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.
Claims (10)
1. An annealing apparatus for a silicon carbide single crystal, comprising:
the crystal box (1), crystal box (1) is porous carbon material box, crystal box (1) includes first bottom plate (101), first annular curb plate (102) and crystal box upper cover (103), first bottom plate (101) with first annular curb plate (102) are around constituteing crystal box cavity (104), crystal box cavity (104) are carborundum single crystal accommodation part, there is trompil (1021) in the axial middle part position of first annular curb plate (102), trompil (1021) are along the circumference of first annular curb plate (102) evenly sets up;
annealing box (2), annealing box (2) are porous carbon material box, annealing box includes second bottom plate (201), second annular curb plate (202) and annealing box upper cover (203), second bottom plate (201) with second annular curb plate (202) are around constituting annealing box cavity, annealing box cavity includes crystal box and holds cavity and carborundum material and hold cavity (204), carborundum powder hold cavity (204) wrap up in around the crystal box holds the cavity.
2. The annealing apparatus as set forth in claim 1, wherein the diameter of the openings (1021) is 0.8mm to 1.2mm, and the interval of the openings (1021) is 60mm to 100mm.
3. The annealing apparatus according to claim 1, wherein the annealing cassette (2) comprises a first annealing cassette comprising a second bottom plate (201), a second annular side plate (202) and an annealing cassette upper cover (203), and at least one second annealing cassette comprising a second bottom plate (201) and a second annular side plate (202);
the first annealing box and the second annealing box and/or the second annealing boxes can be connected through a clamping structure.
4. An annealing method of a silicon carbide single crystal using the annealing apparatus according to any one of claims 1 to 3, characterized by comprising:
placing a silicon carbide single crystal to be annealed in a silicon carbide single crystal accommodating part of a crystal box (1), placing the crystal box (1) in a crystal box accommodating cavity of an annealing box (2), filling silicon carbide powder into a silicon carbide powder accommodating cavity (204) of the annealing box (2), sealing the annealing box (2), placing the annealing box in an annealing furnace, vacuumizing an annealing furnace chamber, introducing inert gas into the annealing furnace chamber, heating under the atmosphere of the inert gas to enable the temperature of the annealing box (2) to rise to a first preset temperature, preserving the heat for a first preset time, and cooling to obtain the annealed silicon carbide single crystal.
5. The annealing method according to claim 4, further comprising: and respectively placing graphite paper layers at the bottom of the silicon carbide single crystal accommodating part, the upper part of the material body formed by the silicon carbide powder material and the lower part of the material body formed by the silicon carbide powder material.
6. The annealing method according to claim 5, wherein a thickness of the graphite paper layer at the bottom of the silicon carbide single crystal accommodation portion is 0.5mm to 2.0mm, a thickness of the graphite paper layer at the upper portion of the body of silicon carbide powder material is 0.5mm to 2.0mm, and a thickness of the graphite paper layer at the lower portion of the body of silicon carbide powder material is 0.5mm to 2.0mm.
7. The annealing method according to claim 4, wherein the inert gas is introduced into the annealing furnace chamber until the pressure of the annealing furnace chamber reaches 35kpa to 45kpa.
8. The annealing method according to claim 4, wherein the first preset temperature is 1700 ℃ to 2100 ℃ and the first preset time is 6h to 8h.
9. The annealing method according to claim 4, wherein the heating rate is 1.5 ℃/min to 2.5 ℃/min.
10. The annealing method according to claim 4, characterized in that the cooling comprises reducing the temperature of the annealing box (2) from the first preset temperature to 1200 ℃ to 1400 ℃ at a first preset cooling rate of 0.7 ℃/min-1.3 ℃/min.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310980904.4A CN116695258B (en) | 2023-08-07 | 2023-08-07 | Annealing device and annealing method for silicon carbide single crystal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310980904.4A CN116695258B (en) | 2023-08-07 | 2023-08-07 | Annealing device and annealing method for silicon carbide single crystal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116695258A true CN116695258A (en) | 2023-09-05 |
| CN116695258B CN116695258B (en) | 2024-01-19 |
Family
ID=87839678
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310980904.4A Active CN116695258B (en) | 2023-08-07 | 2023-08-07 | Annealing device and annealing method for silicon carbide single crystal |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116695258B (en) |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010064919A (en) * | 2008-09-10 | 2010-03-25 | Showa Denko Kk | Method for annealing silicon carbide single crystal material, silicon carbide single crystal wafer, and silicon carbide semiconductor |
| US7767022B1 (en) * | 2006-04-19 | 2010-08-03 | Ii-Vi Incorporated | Method of annealing a sublimation grown crystal |
| CN104357913A (en) * | 2014-12-07 | 2015-02-18 | 中国电子科技集团公司第四十六研究所 | High-temperature annealing treatment method for silicon carbide crystal |
| CN110863247A (en) * | 2019-11-11 | 2020-03-06 | 中科钢研节能科技有限公司 | Secondary annealing method for silicon carbide crystals |
| CN112553694A (en) * | 2021-01-13 | 2021-03-26 | 山西烁科晶体有限公司 | Method and device for high-temperature annealing of silicon carbide single crystal |
| CN213172687U (en) * | 2020-08-27 | 2021-05-11 | 中电化合物半导体有限公司 | Silicon carbide crystal annealing crucible and annealing device |
| CN215628420U (en) * | 2021-05-19 | 2022-01-25 | 山东天岳先进科技股份有限公司 | Annealing carrier for silicon carbide crystals |
| CN115182038A (en) * | 2022-08-16 | 2022-10-14 | 宁波恒普真空科技股份有限公司 | Silicon carbide crystal growth apparatus, system and method |
| CN219385403U (en) * | 2022-12-26 | 2023-07-21 | 苏州优晶光电科技有限公司 | Silicon carbide ingot annealing device and silicon carbide ingot processing equipment |
-
2023
- 2023-08-07 CN CN202310980904.4A patent/CN116695258B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7767022B1 (en) * | 2006-04-19 | 2010-08-03 | Ii-Vi Incorporated | Method of annealing a sublimation grown crystal |
| JP2010064919A (en) * | 2008-09-10 | 2010-03-25 | Showa Denko Kk | Method for annealing silicon carbide single crystal material, silicon carbide single crystal wafer, and silicon carbide semiconductor |
| CN104357913A (en) * | 2014-12-07 | 2015-02-18 | 中国电子科技集团公司第四十六研究所 | High-temperature annealing treatment method for silicon carbide crystal |
| CN110863247A (en) * | 2019-11-11 | 2020-03-06 | 中科钢研节能科技有限公司 | Secondary annealing method for silicon carbide crystals |
| CN213172687U (en) * | 2020-08-27 | 2021-05-11 | 中电化合物半导体有限公司 | Silicon carbide crystal annealing crucible and annealing device |
| CN112553694A (en) * | 2021-01-13 | 2021-03-26 | 山西烁科晶体有限公司 | Method and device for high-temperature annealing of silicon carbide single crystal |
| CN215628420U (en) * | 2021-05-19 | 2022-01-25 | 山东天岳先进科技股份有限公司 | Annealing carrier for silicon carbide crystals |
| CN115182038A (en) * | 2022-08-16 | 2022-10-14 | 宁波恒普真空科技股份有限公司 | Silicon carbide crystal growth apparatus, system and method |
| CN219385403U (en) * | 2022-12-26 | 2023-07-21 | 苏州优晶光电科技有限公司 | Silicon carbide ingot annealing device and silicon carbide ingot processing equipment |
Also Published As
| Publication number | Publication date |
|---|---|
| CN116695258B (en) | 2024-01-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11421343B2 (en) | Method and apparatus for producing bulk silicon carbide using a silicon carbide seed | |
| CN106894091B (en) | Crucible for growing silicon carbide crystal by physical vapor transport method | |
| JP5560862B2 (en) | Silicon carbide single crystal ingot manufacturing equipment | |
| US20210032770A1 (en) | Method for producing bulk silicon carbide | |
| US20120285370A1 (en) | Sublimation growth of sic single crystals | |
| CN214572367U (en) | Silicon carbide crystal growing device | |
| US9376764B2 (en) | Physical vapor transport growth system for simultaneously growing more than one SiC single crystal and method of growing | |
| CN111748843B (en) | Silicon carbide single crystal growth device | |
| CN110396717B (en) | High-quality high-purity semi-insulating silicon carbide single crystal, substrate and preparation method thereof | |
| KR102107626B1 (en) | Apparatus for growing silicon carbide single cryatal and method for growing silicon carbide single cryatal | |
| US11434582B2 (en) | Method for producing bulk silicon carbide by sublimation of a silicon carbide precursor prepared from silicon and carbon particles or particulate silicon carbide | |
| CN214193519U (en) | Unstressed silicon carbide seed crystal fixing device and crucible | |
| TWI774929B (en) | Manufacturing method of silicon carbide single crystal | |
| CN113151897B (en) | Crucible structure | |
| CN108624963A (en) | A kind of raw material sintering process of carborundum crystals for the growth of PVT methods | |
| CN112553694A (en) | Method and device for high-temperature annealing of silicon carbide single crystal | |
| JP2000264795A (en) | Apparatus and method for producing silicon carbide single crystal | |
| CN114941174A (en) | Silicon carbide crystal growth device and filling method | |
| CN116695258B (en) | Annealing device and annealing method for silicon carbide single crystal | |
| KR101619610B1 (en) | Apparatus and method for growing large diameter single crystal | |
| US9512542B2 (en) | Bulk silicon carbide having low defect density | |
| JP2014024705A (en) | Method for producing silicon carbide substrate | |
| CN214120755U (en) | Crucible structure | |
| KR20170073834A (en) | Growth device for silicon carbide single crystal | |
| WO2019176447A1 (en) | Production method and production device of silicon carbide single crystal |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CP03 | Change of name, title or address |
Address after: Factory Building A6 #, No. 555 Dujuan Road, Kunshan Development Zone, Kunshan City, Suzhou City, Jiangsu Province, 215300 Patentee after: Suzhou Youjing Semiconductor Technology Co.,Ltd. Country or region after: China Address before: Factory Building A6 #, No. 555 Dujuan Road, Kunshan Development Zone, Kunshan City, Suzhou City, Jiangsu Province, 215300 Patentee before: SUZHOU U KING PHOTOELECTRIC TECHNOLOGY Co.,Ltd. Country or region before: China |
|
| CP03 | Change of name, title or address |