CN102899718A - Silicon carbide crystal growth method for increasing crystal growth rate - Google Patents
Silicon carbide crystal growth method for increasing crystal growth rate Download PDFInfo
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- CN102899718A CN102899718A CN2012104114360A CN201210411436A CN102899718A CN 102899718 A CN102899718 A CN 102899718A CN 2012104114360 A CN2012104114360 A CN 2012104114360A CN 201210411436 A CN201210411436 A CN 201210411436A CN 102899718 A CN102899718 A CN 102899718A
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Abstract
The invention discloses a silicon carbide crystal growth method for increasing a crystal growth rate. The silicon carbide crystal growth method specifically comprises the following steps: manufacturing a graphite column; filling silicon carbide powder resource into a crucible, and then inserting the graphite column into the silicon carbide powder resource, and placing the crucible assembly into a growth device; firing the silicon carbide powder resource and removing the impurities; taking the graphite column out of the crucible; and performing crystal growth operation. According to the silicon carbide crystal growth method, the problems of the prior art that the use ratio of the silicon carbide powder resource is not high and the average growth rate of the crystal is low are solved.
Description
Technical field
The invention belongs to the artificial crystal growth technical field, be specifically related to a kind of growing silicon carbice crystals method for improving crystal growth rate.
Background technology
Third generation semiconductor material silicon carbide (SiC) has that loose, the critical avalanche breakdown strength of electric field in forbidden band is high, the electronics saturation drift velocity is high, thermal conductivity is high and high temperature resistant, anti-irradiation and the characteristics such as corrosion-resistant, be the preferred material of making the new device such as high-performance electric power electron device, high-power solid state microwave device and solid state sensor and high temperature resistant unicircuit, thereby be widely used in the industries such as oil, chemistry, automobile, Aeronautics and Astronautics, communication, weapon.
Silicon carbide exists without liquid phase under normal engineering specifications, lower about 1800 ℃ of low pressure begins distillation for gas, thereby can not resemble and grow from melt with seed crystal germanium, silicon, the gallium arsenide, can not purify with zone melting method, and existing under the certain condition very easily, the different crystal habits of phase co-conversion (are paramorphism type or homogeneity polytype, Polytype), therefore silicon carbide is one of difficult point of world today's artificial crystal growth.
Mainly contain at present two kinds of silicon carbide whisker preparations: the physical vapor transport method take the body monocrystalline as target (being the seeded sublimation method) and the epitaxial method take film preparation as target.The physical vapor transport method will place the higher crucible bottom of temperature as the carborundum powder of growth source (or silicon, carbon solid mixt) in the prior art, seed crystal is fixed on the lower crucible top of temperature, and growth source distils to decompose under low-voltage high-temperature and produces gaseous substance.Under the driving of the thermograde that exists between by growth source and seed crystal and the pressure gradient that forms, these gaseous substances are transported to the seed crystal position of low temperature naturally, and because the generation of over-saturation degree and crystalline growth, form the silicon carbide of crystalline state.
Prepare in the carborundum crystals process in subliming method, because of warm field distribution problem, the carborundum powder source is inner to be existed axially and radial symmetry gradient, and the space is also arranged between the powder source.Early growth period decomposes the reactant gases that produces near the system high-temperature zone of sidewall of crucible and not only is transported to the crystal aufwuchsplate between sidewall of crucible and powder source, and the while also transports to inside and the bottom in powder source.The gaseous substance that is transported in the powder source continues to transfer to the crystal aufwuchsplate by the space between the powder source on the one hand, on the other hand also can be in the relatively low powder source of temperature inner and bottom take original silicon-carbide particle as the nucleus crystalline growth, so that the particle diameter of the carborundum powder at crystalline growth place increases in the powder source, density increases, voidage reduces, and the gaseous substance that has affected in the powder source is transported to the crystal aufwuchsplate.Further, along with continuing of crystal growth, demixing phenomenon will appear in the carborundum powder source, wherein in the powder source appearance of dense area so that original loose separate SiC particle closely link together, with respect to becoming as a whole, the space between the particle of powder source disappears substantially.After this, distillation, the gaseous substance that decompose to produce only can be transported to the crystal aufwuchsplate between sidewall of crucible and powder source, thereby have affected effectively the transporting of gaseous substance of distillation generation, have reduced crystal growth rate.
In addition, when the distillation of carborundum powder source, decomposition, single silicon-carbide particle is not once all to decompose, disappear, but progressively finish from outside to inside.Particle surface decomposes the carbon that produces will form a carbon shell, wrap undecomposed particle nexine (being designated hereinafter simply as silicon carbide nuclear) fully, and the formation of carbon shell has reduced the net heat conductance in powder source, and the gaseous substance that the silicon carbide nuclear decomposition is produced transports the formation resistance, the decomposition rate reduction that causes silicon carbide to be examined.In addition, carborundum powder near sidewall of crucible distils first, decomposes owing to temperature is relatively high, then along with continuing that crystal is grown, the distillation zone is progressively to relatively low center, the powder source expansion of temperature, and the carbon of the distillation of edge, powder source, decomposition generation exists with the counterfeit type of silicon carbide, reduce the efficient that heat transmits from sidewall of crucible to center, powder source, caused silicon-carbide particle not yet fully distillation decomposition when growth finishes of central zone, powder source.
Because the progressively decomposition (referring to the non-once decomposition) of the densification of carborundum powder source, layering and single silicon-carbide particle that warm field distribution causes prepares in the carborundum crystals process subliming method, along with continuing of crystal growth, gaseous substance effectively transports Efficiency Decreasing to the crystal aufwuchsplate, the distillation rate of decomposition in powder source progressively reduces simultaneously, thereby cause crystal growth rate progressively to reduce, even pause.
Summary of the invention
The purpose of this invention is to provide a kind of growing silicon carbice crystals method for improving crystal growth rate, solved in the prior art the low and not high problem of carborundum powder source utilization ratio of crystal average growth rate.
The technical solution adopted in the present invention is that a kind of growing silicon carbice crystals method for improving crystal growth rate is characterized in that, carries out successively following steps:
Step 2, carry out carborundum powder source sintering and removal of impurities according to existing common process method;
Step 3, from crucible, take out graphite column;
Step 4, carry out the crystal growth operation according to existing common process method.
Wherein, in the step 1, graphite column is inserted in the carborundum powder source of packing in crucible first again.
Perhaps, in the step 1, the graphite column lower surface is provided with outside screw, and the bottom of crucible is provided with threaded hole, and graphite column is threaded connection on crucible; First graphite column is fixed on threadably at the bottom of the crucible, in the crucible of being packed in the carborundum powder source again.
Further, the diameter of graphite column is 5～15mm, and the floorage sum of the graphite column that uses accounts for 20%～40% of its place crucible inner chamber floorage.
Graphite column all extend into crucible bottom, and the graphite column top is higher than carborundum powder source surface 10～20mm.
Further, the inner chamber of institute's use crucible evenly is divided into a plurality of packing zones be used to holding the carborundum powder source in the horizontal direction, the carborundum powder source is respectively charged in each packing zone of crucible in the step 2, and all inserts graphite column in each packing zone.
Wherein, the cross section in each packing zone of crucible is circle and is honeycomb arrangement.
The cross section in each packing zone of crucible is fan-shaped and circumferentially distributes along the center of crucible.
Crucible is the integral type structure.
The invention has the beneficial effects as follows: when filling carborundum powder source, in the carborundum powder source, insert the graphite column of some amount and size, take out graphite column behind the sintering of powder source, thereby in the powder source, having formed the passage that transports of gaseous substance that distillation produces, and then increased the approach that gaseous substance is transported to the crystal aufwuchsplate, weakened the crystalline polamer in the powder source, reduced the densification degree in powder source, increased the supply of the required gaseous substance of growing, improve crystal growth rate, solved the low problem of crystal average growth rate in the prior art.In addition, the inventive method is contained in the carborundum powder source respectively in each packing zone of crucible, can reduce the radial symmetry gradient in the powder source, increase the contact area of powder source and high-temperature zone, improve the powder source temperature at crucible center, increase distillation, the rate of decomposition in powder source, weaken the crystalline polamer in the powder source, suppress the layering in powder source, also can further improve the crystal average growth rate.
Description of drawings
Fig. 1 is growing silicon carbice crystals crucible frock schematic diagram;
Fig. 2 is one of structural representation of the crucible among the present invention;
Fig. 3 be the crucible among the present invention structural representation two;
Wherein, 1. go up thermometer hole, 2. jacket, 3. seed crystal, 4. coil, 5. existing crucible, 6. thermometer hole is 7. descended in the carborundum powder source, 8. crucible, 81. circular packing zones, 82. fan-shaped packing zones.
Embodiment
The present invention is used for improving the growing silicon carbice crystals method of crystal growth rate, carries out successively following steps:
The carborundum powder source is respectively charged in six circular packing zones 81 of crucible, and in each six circular packing zone 81, all inserts graphite column, again crucible 8 is carried out inserting in the SiC Crystal Growth Equipment after the frock.The diameter of graphite column is 5～15mm, and the floorage sum of the graphite column that uses accounts for 20%～40% of its place crucible inner chamber floorage.Graphite column all extend into crucible bottom, and the graphite column top is higher than carborundum powder source surface 10～20mm.
Step 2, carry out carborundum powder source sintering and removal of impurities according to existing common process method.
Step 3, from crucible, take out graphite column.
Step 4, carry out the crystal growth operation according to existing common process method.
Embodiment 2
The present embodiment difference from Example 1 is: in the step 1, the structure of employed crucible 8 is different.As shown in Figure 3, in the present embodiment, crucible 8 inner chambers comprise be used to four fan-shaped packing zones 82 that hold the carborundum powder source, and the cross section in these four fan-shaped packing zones 82 is fan-shaped and circumferentially distributes along the center of crucible in the horizontal direction.Crucible 8 is the integral type structure, and namely being spaced apart with material and integral type mechanism between four fan-shaped packing zones 82 is conducive to the consistence that at high temperature react in silicon carbide part source.The graphite column lower surface is provided with outside screw, and the bottom of crucible is provided with threaded hole, and graphite column is threaded connection on crucible.First graphite column is fixed at the bottom of the crucible threadably, and then quantitative carborundum powder source is respectively charged into crucible.The diameter of graphite column is 5～15mm, and the floorage sum of the graphite column that uses accounts for 20%～40% of its place crucible inner chamber floorage.The graphite column top is higher than carborundum powder source surface 10～20mm.
The inventive method is when filling carborundum powder source, can graphite column be fixed on threadably at the bottom of the crucible in advance, and then quantitative carborundum powder source is respectively charged in the packing zone of crucible, the carborundum powder source of perhaps also can in the packing zone of crucible, packing into first, the graphite column of then in the powder source, inserting some amount and size.Take out graphite column behind the sintering of powder source, thereby the gaseous substance that forms the distillation generation transports passage, gaseous substance transports passage and is conducive to gaseous substance and is transported to the crystal aufwuchsplate, and weakens crystallization and demixing phenomenon in the carborundum powder source, and then improves the utilization ratio in crystal average growth rate and powder source.
The present invention is on the basis of satisfying plan filling powder source capacity requirement, take the contact area that increases powder source and graphite wall, improve the inner powder of crucible source and load homogeneity that portion temperature distributes as target, determine shape, size, what and the concrete distribution in packing district, powder source.In addition, the graphite column of selecting as required among the present invention all extend into crucible bottom, and the graphite column top is higher than carborundum powder source surface 10～20mm, so that operation.Diameter 5～the 15mm of graphite column, the too little meeting of diameter insufficient strength, diameter greatly then affects the quantity in the carborundum powder source of adding dress.The quantity of graphite column determines according to the size of crucible internal diameter, uses the floorage sum of graphite column to account for 20%～40% of its place crucible inner chamber floorage and is advisable, and experimental data shows, this moment, growth velocity was high, and powder source utilization ratio is high.When all the other processing parameter homogeneous phases whiles, with growth time 60 hours and do not adopt the crystal growth experiment of graphite column to compare, the floorage sum of graphite column of the present invention accounts for approximately 23% time of powder source portioning section floorage sum in the crucible, the utilization ratio in powder source has improved 19%, and crystal growth rate has improved 32%; When the floorage sum of graphite column of the present invention accounts for approximately 36% time of portioning section floorage sum in powder source in the crucible, the utilization ratio in powder source has improved 31%, and crystal growth rate has improved 56%.
As shown in Figure 1, when the physical vapor transport method prepares carborundum crystals, with crucible outer setting jacket 2, the up and down two ends center drilling of jacket 2 also forms respectively upper thermometer hole 1 and lower thermometer hole 7, the arranged outside of jacket 2 has coil 4, hold carborundum powder source 6 in crucible, seed crystal 3 is placed in crucible top blind flange below.Under the driving of the thermograde that exists between by growth source and seed crystal and the pressure gradient that forms, these gaseous substances are transported to the seed crystal position of low temperature naturally, and because the generation of over-saturation degree and crystalline growth, form the silicon carbide of crystalline state.Existing crucible 5 is the common graphite crucible, and its inner chamber is cylindrical.
The present invention is in preparation carborundum crystals process, the carborundum powder source is contained in respectively in each packing zone, can reduce the radial symmetry gradient in the powder source, increase the contact area of powder source and high-temperature zone, improve the powder source temperature at crucible center, increase distillation, the rate of decomposition in powder source, weaken the secondary crystal phenomenon in the powder source, suppress the layering in powder source, thereby further improve utilization ratio and the crystal average growth rate in powder source.Select as required the crucible of obstructed inner chamber zoned format among the present invention, how many shapes in packing zone decide according to working condition requirement with in the crucible inner chamber.Load the quality in powder source, the temperature distribution in the powder source, the temperature distribution that part is loaded in the inner powder of crucible source, the factors such as the contact area of powder source and graphite wall, crystal growth time such as consideration of planning.
Claims (9)
1. a growing silicon carbice crystals method that is used for improving crystal growth rate is characterized in that, carries out successively following steps:
Step 1, carborundum powder source and graphite column are packed in the crucible, will insert in the growth apparatus after the crucible frock again;
Step 2, carry out carborundum powder source sintering and removal of impurities;
Step 3, from crucible, take out graphite column;
Step 4, the crystal growth operation of carrying out.
2. according to the growing silicon carbice crystals method for improving crystal growth rate claimed in claim 1, it is characterized in that, in the described step 1, graphite column is inserted in the carborundum powder source of packing in crucible first again.
3. according to the growing silicon carbice crystals method for improving crystal growth rate claimed in claim 1, it is characterized in that, in the described step 1, described graphite column lower surface is provided with outside screw, the bottom of crucible is provided with threaded hole, and described graphite column is threaded connection on crucible; First graphite column is fixed on threadably at the bottom of the crucible, in the crucible of being packed in the carborundum powder source again.
4. according to claim 1,2 or 3 described growing silicon carbice crystals methods for improving crystal growth rate, it is characterized in that, the diameter of described graphite column is 5～15mm, and the floorage sum of the graphite column that uses accounts for 20%～40% of its place crucible inner chamber floorage.
5. according to claim 1,2 or 3 described growing silicon carbice crystals methods for improving crystal growth rate, it is characterized in that, described graphite column all extend into crucible bottom, and the graphite column top is higher than carborundum powder source surface 10～20mm.
6. according to claim 1,2 or 3 described growing silicon carbice crystals methods for improving crystal growth rate, it is characterized in that, the inner chamber of institute's use crucible evenly is divided into a plurality of packing zones be used to holding the carborundum powder source in the horizontal direction, the carborundum powder source is respectively charged in each packing zone of crucible in the step 2, and in each packing zone, all inserts graphite column.
7. according to claim 1,2 or 3 described growing silicon carbice crystals methods for improving crystal growth rate, it is characterized in that, the cross section in described each packing zone is circle and is honeycomb arrangement.
8. according to claim 1,2 or 3 described growing silicon carbice crystals methods for improving crystal growth rate, it is characterized in that, the cross section in described each packing zone is fan-shaped and circumferentially distributes along the center of crucible.
9. according to claim 1,2 or 3 described growing silicon carbice crystals methods for improving crystal growth rate, it is characterized in that, described crucible is the integral type structure.
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Cited By (8)
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| CN103806099A (en) * | 2014-01-20 | 2014-05-21 | 福州阿石创光电子材料有限公司 | Method for preparing titanium oxide crystal |
| CN103805948A (en) * | 2014-01-20 | 2014-05-21 | 福州阿石创光电子材料有限公司 | Titanium crystal sintering die |
| CN107740193A (en) * | 2017-10-12 | 2018-02-27 | 钢铁研究总院 | A kind of gradient temperature field multichannel honeycomb array crucible |
| CN110396723A (en) * | 2019-07-12 | 2019-11-01 | 山东天岳先进材料科技有限公司 | A kind of high-purity semi-insulating silicon carbide monocrystalline and its high efficiency preparation method and application |
| CN112585304A (en) * | 2020-04-14 | 2021-03-30 | 眉山博雅新材料有限公司 | Crystal growth method and device |
| CN114059163A (en) * | 2021-11-17 | 2022-02-18 | 宁波合盛新材料有限公司 | Silicon carbide crystal growth crucible and growth method |
| CN115893419A (en) * | 2022-10-18 | 2023-04-04 | 宁波合盛新材料有限公司 | Preparation method and preparation device of silicon carbide |
| CN116555898A (en) * | 2022-07-01 | 2023-08-08 | 浙江晶越半导体有限公司 | Silicon carbide crucible structure grown by PVT method with high powder source utilization rate and growth method thereof |
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Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103806099A (en) * | 2014-01-20 | 2014-05-21 | 福州阿石创光电子材料有限公司 | Method for preparing titanium oxide crystal |
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| CN110396723A (en) * | 2019-07-12 | 2019-11-01 | 山东天岳先进材料科技有限公司 | A kind of high-purity semi-insulating silicon carbide monocrystalline and its high efficiency preparation method and application |
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| CN114059163A (en) * | 2021-11-17 | 2022-02-18 | 宁波合盛新材料有限公司 | Silicon carbide crystal growth crucible and growth method |
| CN116555898A (en) * | 2022-07-01 | 2023-08-08 | 浙江晶越半导体有限公司 | Silicon carbide crucible structure grown by PVT method with high powder source utilization rate and growth method thereof |
| CN115893419A (en) * | 2022-10-18 | 2023-04-04 | 宁波合盛新材料有限公司 | Preparation method and preparation device of silicon carbide |
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