CN114525586B - Growth method for preparing large-size high-purity semi-insulating silicon carbide single crystal - Google Patents
Growth method for preparing large-size high-purity semi-insulating silicon carbide single crystal Download PDFInfo
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- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 title claims abstract description 140
- 229910010271 silicon carbide Inorganic materials 0.000 title claims abstract description 140
- 239000013078 crystal Substances 0.000 title claims abstract description 137
- 238000000034 method Methods 0.000 title claims abstract description 59
- 238000011010 flushing procedure Methods 0.000 claims abstract description 68
- 239000007789 gas Substances 0.000 claims description 71
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 33
- 229910002804 graphite Inorganic materials 0.000 claims description 33
- 239000010439 graphite Substances 0.000 claims description 33
- 239000002994 raw material Substances 0.000 claims description 29
- 238000010926 purge Methods 0.000 claims description 22
- 238000009413 insulation Methods 0.000 claims description 14
- 238000004321 preservation Methods 0.000 claims description 14
- 238000010438 heat treatment Methods 0.000 claims description 9
- 239000011261 inert gas Substances 0.000 claims description 6
- 239000011148 porous material Substances 0.000 claims description 5
- 239000000463 material Substances 0.000 claims description 4
- 230000001681 protective effect Effects 0.000 claims description 3
- 239000012535 impurity Substances 0.000 abstract description 42
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 abstract description 32
- 229910052757 nitrogen Inorganic materials 0.000 abstract description 16
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 abstract description 14
- 229910052796 boron Inorganic materials 0.000 abstract description 14
- 238000004519 manufacturing process Methods 0.000 abstract description 7
- 238000003912 environmental pollution Methods 0.000 abstract description 3
- 238000005086 pumping Methods 0.000 description 9
- 230000000087 stabilizing effect Effects 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- XUKUURHRXDUEBC-SXOMAYOGSA-N (3s,5r)-7-[2-(4-fluorophenyl)-3-phenyl-4-(phenylcarbamoyl)-5-propan-2-ylpyrrol-1-yl]-3,5-dihydroxyheptanoic acid Chemical compound C=1C=CC=CC=1C1=C(C=2C=CC(F)=CC=2)N(CC[C@@H](O)C[C@H](O)CC(O)=O)C(C(C)C)=C1C(=O)NC1=CC=CC=C1 XUKUURHRXDUEBC-SXOMAYOGSA-N 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 2
- 238000002109 crystal growth method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 102000029749 Microtubule Human genes 0.000 description 1
- 108091022875 Microtubule Proteins 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007770 graphite material Substances 0.000 description 1
- 210000004688 microtubule Anatomy 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 238000005406 washing 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
- 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
-
- 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
- C30B23/00—Single-crystal growth by condensing evaporated or sublimed materials
-
- 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
Abstract
The invention provides a silicon carbide crystal growth furnace in a working state. The invention also provides a growth method for preparing the large-size high-purity semi-insulating silicon carbide single crystal, which adds a key process of flushing a cavity at high temperature and high pressure and high flow rate before the growth of the silicon carbide crystal, can effectively protect the silicon carbide seed crystal from being damaged at high pressure, volatilizes or desorbs impurities such as nitrogen and boron adsorbed in a system at high temperature, and can effectively take away the impurities such as nitrogen and boron in the volatilized or desorbed state by the high-flow rate flushing. Meanwhile, the structure of production equipment and the complexity of production process are not increased, the method is simple and effective, and the environmental pollution is not increased.
Description
Technical Field
The invention belongs to the technical field of silicon carbide crystal growth, relates to a silicon carbide crystal growth furnace in a working state and a silicon carbide crystal growth method, and particularly relates to a growth method for preparing a large-size high-purity semi-insulating silicon carbide single crystal.
Background
The existing preparation technology of high-purity semi-insulating silicon carbide crystals generally prepares high-purity silicon carbide raw materials to obtain silicon carbide raw materials with low nitrogen, boron, aluminum and other impurities, then assists in removing impurities in a vacuum chamber before growth, and then introduces an atmosphere capable of removing nitrogen, boron and other impurities, such as H, in the growth process 2 、Cl 2 、CH 4 、H 2 S, growing for a certain period of time, and finally obtaining the high-purity semi-insulating silicon carbide crystal.
Although the method for removing impurities in the growth chamber before growth is numerous, or the molecular pump is used for carrying out the long-time limit vacuumizing at normal temperature, the back vacuum can reach 10 -5 Pa, this method is effective in removing free nitrogen, but it is still difficult to remove some impurities, thereby affecting the quality of the final silicon carbide crystal.
Therefore, how to find a suitable way to better remove impurities in the growth chamber, thereby improving the crystal quality of the grown silicon carbide, has become one of the great concerns of many research and development enterprises and first-line researchers in the industry.
Disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide a silicon carbide crystal growing furnace and a silicon carbide crystal growing method under working conditions, particularly a growing method for preparing a large-size high-purity semi-insulating silicon carbide single crystal.
The invention provides a silicon carbide crystal growth furnace in a working state, which is characterized by comprising a crystal growth furnace body;
a graphite crucible disposed in a growth chamber of the crystal growth furnace;
a silicon carbide raw material placed in the crucible and a silicon carbide seed crystal placed on the top of the crucible;
the temperature of the growth chamber is 2000-2800 ℃;
a purge gas is provided within the growth chamber.
Preferably, the purge gas is a flowing purge gas;
the pressure of the flushing gas is 3-7 ten thousand Pa;
the purge gas comprises inert gas, H 2 、H 2 S and CH 4 One or more of the following.
Preferably, the crucible is provided with a flushing gas therein;
the pores of the graphite crucible are provided with flushing gas;
a heat preservation felt is arranged around the crucible;
the heat preservation felt is provided with a flushing gas.
Preferably, the time for the flushing gas is 10-1000 min;
the crucible comprises a graphite crucible;
the insulation blanket comprises a graphite insulation blanket.
The invention provides a growth method of silicon carbide crystals, which comprises the following steps:
1) Placing a crucible containing a silicon carbide seed crystal and a silicon carbide raw material into a growth chamber of a crystal growth furnace;
2) And (3) after vacuumizing the growth chamber, heating, filling flushing gas for flushing, and then performing crystal growth to obtain the silicon carbide crystal.
Preferably, a heat preservation felt is arranged around the crucible;
the graphite crucible, the heat preservation felt and the silicon carbide raw materials are all high-purity materials;
the purity of the graphite crucible, the heat preservation felt and the silicon carbide raw material is more than or equal to 99.9999 percent.
Preferably, the vacuum-pumping treatment comprises normal temperature vacuum-pumping treatment and medium temperature vacuum-pumping treatment;
the vacuum pressure of the normal temperature vacuuming treatment is 10 -5 ～10Pa；
The temperature of the medium-temperature vacuumizing treatment is 50-1400 ℃;
the vacuum pressure of the medium-temperature vacuumizing treatment is 10 -5 ～10Pa。
Preferably, after the vacuuming treatment, the method further comprises the step of filling a protective gas;
the flushing step is a high-temperature high-pressure high-flow flushing process;
the temperature of the flushing step is 2000-2800 ℃;
the pressure of the flushing gas in the flushing step is 3-7 ten thousand Pa.
Preferably, the flow rate of the flushing gas in the flushing step is 500-5000 sccm;
the time of the flushing step is 10-1000 min;
the purge gas comprises inert gas, H 2 、H 2 S and CH 4 One or more of the following;
the flushing step is specifically to flush with flowing flushing gas.
Preferably, the silicon carbide crystals have a size of 4 to 8 inches;
the silicon carbide crystal comprises a silicon carbide single crystal;
the silicon carbide crystal comprises a high purity semi-insulating silicon carbide crystal.
The invention provides a silicon carbide crystal growth furnace in a working state, which comprises a crystal growth furnace body; a graphite crucible disposed in a growth chamber of the crystal growth furnace; a silicon carbide raw material placed in the crucible and a silicon carbide seed crystal placed on the top of the crucible; the temperature of the growth chamber is 2000-2800 ℃; a purge gas is provided within the growth chamber. Compared with the prior art, the method aims at solving the problems that the prior method for removing impurities in the growth chamber before the growth of the silicon carbide crystal still has difficulty in removing part of impurities, the removal is not thorough, and the growth of the silicon carbide crystal is affected. The present inventors have studied that the conventional removal method can effectively remove free nitrogen, but it is difficult to remove impurities adsorbed on porous insulation felt and graphite material. Although the vacuum chamber is vacuumized for a long time for impurity removal in a medium temperature section (about 1200 ℃), the impurity removal effect is not ideal because the temperature of the section is still not high, and when the temperature is further increased to more than 1400 ℃ under low pressure, the morphology of the silicon carbide seed crystal is changed, and crystals containing a large number of microtubule defects are grown.
Based on the method, the silicon carbide crystal growth furnace system under the working state is creatively obtained through a specific impurity removal mode. The invention adopts the key technology of high-temperature high-pressure high-flow flushing chamber before the growth of silicon carbide crystal, the high-pressure can effectively protect the silicon carbide seed crystal from being damaged, the high-temperature can volatilize or desorb impurities such as nitrogen, boron and the like adsorbed in the system, the high-flow flushing can effectively take away the impurities such as nitrogen, boron and the like in the volatilized or desorbed state, especially the high-flow flushing gas can enter the holes of the graphite piece and the pores of the heat preservation felt in the growth chamber, the impurities adsorbed on the porous heat preservation felt and the graphite piece can be effectively removed, the impurities in the growth system are further reduced, and the impurity content in the chamber system before the growth of the silicon carbide crystal can be greatly reduced, so that the high-quality high-purity semi-insulating silicon carbide crystal is obtained.
According to the invention, a key process of flushing the cavity at high temperature and high pressure in a large flow manner is added before the growth of the silicon carbide crystal, so that the silicon carbide seed crystal can be effectively protected from being damaged at high pressure, impurities such as nitrogen and boron adsorbed in the system can be volatilized or desorbed at high temperature, the impurities such as nitrogen and boron in the volatilized or desorbed state can be effectively taken away by large-flow flushing, the impurity content in the cavity system before the growth of the silicon carbide crystal can be greatly reduced by the process, and the high-quality high-purity silicon carbide crystal can be obtained by growth. Meanwhile, the structure of production equipment and the complexity of production process are not increased, the method is simple and effective, and the environmental pollution is not increased.
The method for growing the silicon carbide crystal, namely the treatment method before growing the silicon carbide crystal, provided by the invention, has the advantages that the impurity content is simply and effectively reduced, the resistivity of the high-purity semi-insulating silicon carbide crystal is improved, and the high-resistivity high-purity semi-insulating silicon carbide crystal is obtained.
Experimental results show that compared with the conventional process, the impurity content of the grown crystal is obviously reduced, the impurity N is reduced by 1-N times, the impurity B is reduced by 1-2 times, the resistivity of the corresponding high-purity wafer is obviously improved, the resistivity of the high-purity semi-insulating wafer is improved by 1-3 orders of magnitude, and the requirements of the resistivity index of the high-purity semi-insulating crystal are completely met.
Drawings
FIG. 1 is a schematic diagram of a silicon carbide crystal growth furnace system according to the present invention;
FIG. 2 is a graph showing the resistivity of a high purity semi-insulating silicon carbide wafer prepared according to comparative example 1 of the present invention;
FIG. 3 is a graph showing the resistivity of a high purity semi-insulating silicon carbide wafer prepared in example 1 of the present invention;
FIG. 4 shows the resistivity of a high purity semi-insulating silicon carbide wafer prepared in example 2 of the present invention.
Detailed Description
For further understanding of the present invention, the technical aspects of the present invention will be clearly and fully described in connection with the following embodiments, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
All the raw materials of the present invention are not particularly limited in their sources, and may be purchased on the market or prepared according to conventional methods well known to those skilled in the art.
The purity of all the raw materials of the present invention is not particularly limited, and the present invention is preferably carried out with a purity which is conventional in the field of high purity or silicon carbide crystal production.
The invention provides a silicon carbide crystal growth furnace in a working state, which comprises a crystal growth furnace body;
a graphite crucible disposed in a growth chamber of the crystal growth furnace;
a silicon carbide raw material placed in the crucible and a silicon carbide seed crystal placed on the top of the crucible;
the temperature of the growth chamber is 2000-2800 ℃;
a purge gas is provided within the growth chamber.
In the present invention, the temperature of the growth chamber is preferably 2000 to 2800 ℃, more preferably 2100 to 2700 ℃, more preferably 2200 to 2600 ℃, more preferably 2300 to 2500 ℃.
In the present invention, the crucible preferably comprises a graphite crucible.
In the invention, a heat insulation felt is preferably arranged around the crucible.
In the present invention, the insulation blanket preferably comprises a graphite insulation blanket.
In the present invention, the crucible preferably has a purge gas therein. More specifically, the pores of the graphite crucible have a purge gas therein.
In the present invention, the heat insulation blanket preferably has a purge gas therein. Specifically, the heat-insulating felt comprises gaps of the heat-insulating felt.
In the present invention, the purge gas is preferably a flowing purge gas. Specifically, the flow direction of the flushing gas is not limited, but after the air inlet is opened, the air outlet is opened, so that the flushing gas flows.
In the present invention, the pressure of the purge gas is preferably 3 to 7 Pa, more preferably 3.5 to 6.5 Pa, still more preferably 4 to 6 Pa, and still more preferably 4.5 to 5.5 Pa.
In the present invention, the purge gas preferably includes an inert gas, H 2 、H 2 S and CH 4 One or more of them, more preferably Ar, H 2 、H 2 S or CH 4 . Specifically, the purity of the flushing gas is greater than or equal to 99.9999%.
In the present invention, the time for having the purge gas is preferably 10 to 1000 minutes, more preferably 100 to 900 minutes, more preferably 200 to 800 minutes, more preferably 300 to 700 minutes, more preferably 400 to 600 minutes.
Referring to fig. 1, fig. 1 is a schematic diagram of a structure of a silicon carbide crystal growth furnace body provided by the invention. The device comprises a silicon carbide seed crystal 1, a graphite crucible 2, a silicon carbide raw material 3, a thermal insulation felt 4, a growth chamber 5.
The invention provides a growth method of silicon carbide crystals, which comprises the following steps:
1) Placing a crucible containing a silicon carbide seed crystal and a silicon carbide raw material into a growth chamber of a crystal growth furnace;
2) And (3) after vacuumizing the growth chamber, heating, filling flushing gas for flushing, and then performing crystal growth to obtain the silicon carbide crystal.
The invention firstly places a crucible containing silicon carbide seed crystal and silicon carbide raw material into a growth chamber of a crystal growth furnace.
In the invention, a heat insulation felt is preferably arranged around the crucible.
In the invention, the graphite crucible, the heat insulation felt and the silicon carbide raw material are all preferably high-purity materials.
In the present invention, the purity of the graphite crucible, the insulation blanket, and the silicon carbide raw material is preferably 99.9999% or more, more preferably 99.99993% or more, still more preferably 99.99997% or more, and still more preferably 99.99999% or more.
Finally, the growth chamber is preferably vacuumized, then heated, filled with flushing gas for flushing, and then crystal growth is carried out to obtain the silicon carbide crystal.
In the present invention, the vacuum-pumping treatment preferably includes a normal temperature vacuum-pumping treatment and a medium temperature vacuum-pumping treatment.
In the present invention, the vacuum pressure of the normal temperature vacuuming treatment is preferably an extreme vacuum. Specifically, it may be 10 -5 About 10Pa, may be 10 -5 About 1Pa, may be 10 -5 ～10 -1 Pa, may be 10 -5 ～10 -2 Pa, more preferably 5 x 10 -4 ～10 -3 Pa。
In the present invention, the temperature at the normal temperature is preferably 5 to 40 ℃, more preferably 10 to 35 ℃, and still more preferably 15 to 30 ℃.
In the present invention, the temperature of the medium-temperature vacuum-pumping treatment is preferably 50 to 1400 ℃, more preferably 250 to 1200 ℃, more preferably 500 to 1000 ℃, more preferably 600 to 900 ℃.
In the present invention, the vacuum pressure of the medium temperature vacuuming treatment is preferably a limiting vacuum. Specifically, it may be 10 -5 About 10Pa, may be 10 -5 About 1Pa, may be 10 -5 ～10 -1 Pa, may be 10 -5 ～10 -2 Pa, more preferably 5 x 10 -4 ～10 -3 Pa。
In the present invention, the vacuum-pumping treatment is preferably further followed by a step of charging a shielding gas. Specifically, the shielding gas comprises inert gas, H 2 、H 2 S and CH 4 One or more of them, more preferably Ar, H 2 、H 2 S or CH 4 . The pressure of the shielding gas is preferably 1 to 8 Pa, more preferably 2 to 7 Pa, and still more preferably 3 to 6 Pa. Before growth, the protective gas is injected to maintain a certain gas pressure at a temperature above the medium temperature, so as to avoid the influence of the temperature on the raw materials such as crystals.
In the present invention, the rinsing step is preferably a high temperature high pressure high flow rinsing process.
In the present invention, the temperature of the washing step is preferably 2000 to 2800 ℃, more preferably 2100 to 2700 ℃, more preferably 2200 to 2600 ℃, more preferably 2300 to 2500 ℃.
In the present invention, the pressure of the purge gas in the purge step is preferably 3 to 7 Pa, more preferably 3.5 to 6.5 Pa, still more preferably 4 to 6 Pa, and still more preferably 4.5 to 5.5 Pa.
In the present invention, the flow rate of the purge gas in the purge step is preferably 500 to 5000sccm, more preferably 1500 to 4000sccm, and still more preferably 2500 to 3000sccm.
In the present invention, the time of the rinsing step is preferably 10 to 1000 minutes, more preferably 210 to 800 minutes, and still more preferably 410 to 600 minutes.
In the present invention, the purge gas preferably includes an inert gas, H 2 、H 2 S and CH 4 One or more of them, more preferably Ar, H 2 、H 2 S or CH 4 。
In the present invention, the flushing step is particularly preferably flushing with a flowing flushing gas.
In the present invention, the silicon carbide crystal preferably has a size of 4 to 8 inches, more preferably 4.5 to 7.5 inches, still more preferably 5 to 7 inches, and still more preferably 5.5 to 6.5 inches.
In the present invention, the silicon carbide crystal preferably includes a silicon carbide single crystal.
In the present invention, the silicon carbide crystal preferably comprises a high-purity semi-insulating silicon carbide crystal.
The invention is a complete and refined integral technical proposal, which better reduces the impurity in the growth process of the silicon carbide crystal and improves the quality of the grown silicon carbide single crystal, and the growth method of the silicon carbide crystal can concretely comprise the following steps:
a growth method for preparing a high-purity semi-insulating silicon carbide single crystal or a treatment method before growth of a silicon carbide crystal, the system comprising: graphite crucible, silicon carbide seed crystal, high-purity silicon carbide raw material, heat preservation felt and growth chamber. Wherein, graphite crucible, heat preservation felt are graphite goods, and the heat preservation felt is located around the crucible.
A certain amount of high-purity silicon carbide raw material is filled into a crucible, silicon carbide seed crystals are arranged on the top of a graphite crucible, and a high-temperature high-pressure high-flow flushing process is added except for the long-time pre-pumping of a growth chamber at a low temperature and a medium temperature section before the crystal growth, so that the impurity content in a growth system is greatly reduced, and the high-resistivity high-purity semi-insulating silicon carbide crystal is obtained.
Specifically, the growth system comprises a growth cavity, a graphite crucible, a thermal insulation felt, a silicon carbide raw material and a silicon carbide seed crystal.
Specifically, the graphite crucible, the heat preservation felt and the silicon carbide raw materials are all high-purity, and the purity is more than 99.9999%.
Specifically, the high-temperature high-pressure high-flow flushing process has the pressure of 3-7 ten thousand Pa. The high-temperature high-pressure high-flow flushing process is carried out at the temperature of 2000-2800 ℃. The high-temperature high-pressure high-flow flushing process is carried out for 10-1000 min.
Specifically, the flow direction of the high-flow flushing gas is not limited, and the gas comprises Ar/H 2 /H 2 S/CH 4 The purity of the gas is more than or equal to 99.9999 percent.
Specifically, the high-temperature high-pressure high-flow flushing process is suitable for preparing 4-8 inch high-purity semi-insulating silicon carbide crystals.
According to the invention, a key process of flushing the cavity at high temperature and high pressure in a large flow manner is added before the growth of the silicon carbide crystal, the silicon carbide seed crystal can be effectively protected from being damaged at high pressure, impurities such as nitrogen and boron adsorbed in the system can be volatilized or desorbed at high temperature, the impurities such as nitrogen and boron in the volatilized or desorbed state can be effectively taken away by large-flow flushing, the impurity content in the cavity system before the growth of the silicon carbide crystal can be greatly reduced by the process, and the high-quality high-purity silicon carbide crystal can be obtained by growth.
The above steps of the present invention provide a growth method for preparing a large-size high-purity semi-insulating silicon carbide single crystal. The invention obtains the silicon carbide crystal growth furnace system under the working state by a specific impurity removal mode. The invention adopts the key technology of high-temperature high-pressure high-flow flushing chamber before the growth of silicon carbide crystal, the high-pressure can effectively protect the silicon carbide seed crystal from being damaged, the high-temperature can volatilize or desorb impurities such as nitrogen, boron and the like adsorbed in the system, the high-flow flushing can effectively take away the impurities such as nitrogen, boron and the like in the volatilized or desorbed state, especially the high-flow flushing gas can enter the holes of the graphite piece and the pores of the heat preservation felt in the growth chamber, the impurities adsorbed on the porous heat preservation felt and the graphite piece can be effectively removed, the impurities in the growth system are further reduced, and the impurity content in the chamber system before the growth of the silicon carbide crystal can be greatly reduced, so that the high-quality high-purity semi-insulating silicon carbide crystal is obtained.
According to the invention, a key process of flushing the cavity at high temperature and high pressure in a large flow manner is added before the growth of the silicon carbide crystal, so that the silicon carbide seed crystal can be effectively protected from being damaged at high pressure, impurities such as nitrogen and boron adsorbed in the system can be volatilized or desorbed at high temperature, the impurities such as nitrogen and boron in the volatilized or desorbed state can be effectively taken away by large-flow flushing, the impurity content in the cavity system before the growth of the silicon carbide crystal can be greatly reduced by the process, and the high-quality high-purity silicon carbide crystal can be obtained by growth. Meanwhile, the structure of production equipment and the complexity of production process are not increased, the method is simple and effective, and the environmental pollution is not increased.
The method for growing the silicon carbide crystal, namely the treatment method before growing the silicon carbide crystal, provided by the invention, has the advantages that the impurity content is simply and effectively reduced, the resistivity of the high-purity semi-insulating silicon carbide crystal is improved, and the high-resistivity high-purity semi-insulating silicon carbide crystal is obtained.
Experimental results show that compared with the conventional process, the impurity content of the grown crystal is obviously reduced, the impurity N is reduced by 1-N times, the impurity B is reduced by 1-2 times, the resistivity of the corresponding high-purity wafer is obviously improved, the resistivity of the high-purity semi-insulating wafer is improved by 1-3 orders of magnitude, and the requirements of the resistivity index of the high-purity semi-insulating crystal are completely met.
For further explanation of the present invention, the silicon carbide crystal growth furnace and the silicon carbide crystal growth method under one working state provided by the present invention are described in detail with reference to the following examples, but it should be understood that these examples are implemented on the premise of the technical scheme of the present invention, and detailed implementation and specific operation procedures are given only for further explanation of the features and advantages of the present invention, and not limitation of the claims of the present invention, and the scope of protection of the present invention is not limited to the following examples.
Comparative example 1
High-temperature-free high-pressure high-flow flushing process for growing silicon carbide crystal
Raw materials such as silicon carbide raw materials, a graphite crucible, silicon carbide seed crystals and the like are assembled according to the figure 1 and put into a heat-preserving barrel of a growth chamber of a single crystal furnace, and are closely packedSealing the chamber and vacuumizing to 10 -5 And (3) Pa, heating to 1200 ℃, continuously vacuumizing for 2 hours, filling gas (Ar gas or Ar/H mixed gas) required by growth to 7 Pa, heating to 2100 ℃, gradually reducing the gas pressure to the required growth pressure of 1000Pa for 100 minutes, and then growing for a certain period of time to obtain the silicon carbide crystal.
After the crystal obtained by growth is processed and sliced, the wafer resistivity result shows that: the minimum value of the resistivity of the high-purity wafer is 4.71E+8Ω cm (shown in figure 2), which is higher than the high-purity semi-insulating resistivity of more than 10 in the industry 5 Omega cm, but this result still does not meet some industry customer requirements for resistivities greater than 1e+9Ω cm; SIMS test gave a wafer N content of 1.85E+16/cm -3 B content is 3.88E+15/cm -3 The high purity requirement is achieved.
Referring to fig. 2, fig. 2 is a graph showing the resistivity of the high purity semi-insulating silicon carbide wafer prepared in comparative example 1 of the present invention.
Example 1
Silicon carbide crystal growing by high-temperature high-pressure high-flow flushing process
Raw materials such as silicon carbide raw materials, a graphite crucible, silicon carbide seed crystals and the like are assembled according to the figure 1, put into a heat-preserving barrel of a growth chamber of a single crystal furnace, and the chamber is sealed and vacuumized to 10 -5 Pa, heating to 1200 ℃, continuously vacuumizing for 2H, charging gas (Ar gas or Ar/H mixed gas) required by growth to 7 Pa, heating to 2300 ℃, charging flushing gas (Ar gas or Ar/H mixed gas) with the flow of 5000sccm, starting a pressure control pump, continuously flushing and extracting gas to achieve the aim of flushing, stabilizing the pressure at 7 Pa, controlling the pressure for 200min, then reducing the temperature to 2100 ℃, stabilizing the temperature, gradually reducing the temperature to the required growth pressure of 1000Pa, and growing for a certain period of time to obtain the silicon carbide crystal.
After the crystal obtained by growth is processed and sliced, the wafer resistivity result shows that: the minimum value of the resistivity of the high-purity wafer is 6.2E+9Ω cm (shown in figure 3), which is higher than the high-purity semi-insulating resistivity of more than 10 in the industry 5 Omega cm, which meets the requirements of some industrial customers that the resistivity is greater than 1E+9omega cm; SIMS test gave a wafer N content of 1.06E+16/cm -3 B content is2.22E+15 pieces/cm -3 The high purity requirement is achieved.
Referring to fig. 3, fig. 3 shows the resistivity of the high purity semi-insulating silicon carbide wafer prepared in example 1 of the present invention.
Example 2
Silicon carbide crystal growing by high-temperature high-pressure high-flow flushing process
Raw materials such as silicon carbide raw materials, a graphite crucible, silicon carbide seed crystals and the like are assembled according to the figure 1, put into a heat-preserving barrel of a growth chamber of a single crystal furnace, and the chamber is sealed and vacuumized to 10 -5 Pa, heating to 1200 ℃, continuously vacuumizing for 2H, charging gas (Ar gas or Ar/H mixed gas) required by growth to 7 Pa, heating to 2500 ℃, charging flushing gas (Ar gas or Ar/H mixed gas) with the flow of 5000sccm, starting a pressure control pump, continuously flushing and extracting gas to achieve the aim of flushing, stabilizing the pressure at 7 Pa, controlling the pressure for 300min, then reducing the temperature to 2100 ℃, gradually reducing the temperature to the required growth pressure of 1000Pa after stabilizing the temperature, and then growing for a certain period of time to obtain the silicon carbide crystal.
After the crystal obtained by growth is processed and sliced, the wafer resistivity result shows that: the minimum value of the resistivity of the high-purity wafer is 4.62E+1Ω cm (shown in figure 4), which is higher than the high-purity semi-insulating resistivity of more than 10 in the industry 5 Omega cm, which meets the requirements of some industrial customers that the resistivity is greater than 1E+9omega cm; SIMS test results in wafer N content less than 1E+16/cm -3 B content is 1.9E+15/cm -3 The high purity requirement is achieved.
Referring to fig. 4, fig. 4 shows the resistivity of the high purity semi-insulating silicon carbide wafer prepared in example 2 of the present invention.
The foregoing has outlined rather broadly the principles and embodiments of the present invention in order that the detailed description of the invention may be better understood, and in order that the best mode may be understood, and in order that the present invention may be practiced by anyone skilled in the art, including in any regard to making and using any devices or systems and performing any incorporated methods. It should be noted that it will be apparent to those skilled in the art that various modifications and adaptations of the invention can be made without departing from the principles of the invention and these modifications and adaptations are intended to be within the scope of the invention as defined in the following claims. The scope of the patent protection is defined by the claims and may include other embodiments that occur to those skilled in the art. Such other embodiments are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
Claims (10)
1. A method for growing a silicon carbide crystal, comprising the steps of:
1) Placing a graphite crucible containing silicon carbide seed crystals and silicon carbide raw materials into a growth chamber of a crystal growth furnace;
2) After the growth chamber is vacuumized, filling protective gas, heating, filling flushing gas for flushing, and then growing crystals to obtain silicon carbide crystals;
the silicon carbide crystal growing furnace in the working state in the step 2) comprises a crystal growing furnace body;
a graphite crucible disposed in a growth chamber of the crystal growth furnace;
a silicon carbide raw material placed in the crucible and a silicon carbide seed crystal placed on the top of the crucible;
the vacuumizing treatment comprises normal-temperature vacuumizing treatment and medium-temperature vacuumizing treatment;
the vacuum pressure of the normal temperature vacuuming treatment is 10 -5 ~10Pa；
The temperature of the medium-temperature vacuumizing treatment is 50-1400 ℃;
the vacuum pressure of the medium-temperature vacuumizing treatment is 10 -5 ~10Pa；
The temperature of the flushing step is 2000-2800 ℃;
the pressure of the flushing gas in the flushing step is 3-7 Pa;
the flow rate of the flushing gas in the flushing step is 500-5000 sccm;
the time of the flushing step is 10-1000 min;
the purge gas comprises inert gas and/or H 2 ；
The flushing step is specifically to flush by flowing flushing gas;
the crucible is provided with a flushing gas.
2. A method of growing according to claim 1 wherein the pores of the graphite crucible have a purge gas therein.
3. A method of growing according to claim 1, wherein a heat insulating felt is further provided around the crucible;
the heat preservation felt is provided with a flushing gas.
4. A method of growing according to claim 3 wherein the insulation blanket comprises a graphite insulation blanket.
5. A method of growing according to claim 1, wherein a heat insulating felt is provided around the crucible.
6. The method according to claim 5, wherein the graphite crucible, the insulating felt and the silicon carbide raw material are all high-purity materials.
7. The method according to claim 5, wherein the purity of the graphite crucible, the insulating felt, and the silicon carbide material is 99.9999% or more.
8. The method of claim 1, wherein the silicon carbide crystal has a size of 4 to 8 inches.
9. A method of growing according to claim 1 wherein the silicon carbide crystal comprises a single crystal of silicon carbide.
10. A method of growing according to claim 1 wherein the silicon carbide crystal comprises a high purity semi-insulating silicon carbide crystal.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104947182A (en) * | 2015-07-16 | 2015-09-30 | 中国电子科技集团公司第四十六研究所 | Method for rapidly growing large-size high-purity semi-insulating silicon carbide single crystal |
| CN206244919U (en) * | 2016-12-09 | 2017-06-13 | 河北同光晶体有限公司 | A kind of grower of semi-insulation SiC monocrystalline |
| CN106968017A (en) * | 2017-03-28 | 2017-07-21 | 山东大学 | Crucible for growing high-purity semi-insulating silicon carbide crystalloid |
| CN110203933A (en) * | 2019-04-28 | 2019-09-06 | 河北同光晶体有限公司 | A kind of method of nitrogen impurity content in reduction silicon carbide powder |
| CN113550009A (en) * | 2021-07-27 | 2021-10-26 | 河北天达晶阳半导体技术股份有限公司 | Method and device for growing high-purity silicon carbide single crystal |
-
2021
- 2021-12-30 CN CN202111668217.6A patent/CN114525586B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104947182A (en) * | 2015-07-16 | 2015-09-30 | 中国电子科技集团公司第四十六研究所 | Method for rapidly growing large-size high-purity semi-insulating silicon carbide single crystal |
| CN206244919U (en) * | 2016-12-09 | 2017-06-13 | 河北同光晶体有限公司 | A kind of grower of semi-insulation SiC monocrystalline |
| CN106968017A (en) * | 2017-03-28 | 2017-07-21 | 山东大学 | Crucible for growing high-purity semi-insulating silicon carbide crystalloid |
| CN110203933A (en) * | 2019-04-28 | 2019-09-06 | 河北同光晶体有限公司 | A kind of method of nitrogen impurity content in reduction silicon carbide powder |
| CN113550009A (en) * | 2021-07-27 | 2021-10-26 | 河北天达晶阳半导体技术股份有限公司 | Method and device for growing high-purity silicon carbide single crystal |
Non-Patent Citations (1)
| Title |
|---|
| 高纯半绝缘SiC电阻率影响因素;吴会旺;赵丽霞;刘英斌;李胜华;;微纳电子技术(第04期);第320-323页 * |
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