WO2014132561A1 - 炭化珪素の製造方法および炭化珪素 - Google Patents
炭化珪素の製造方法および炭化珪素 Download PDFInfo
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- WO2014132561A1 WO2014132561A1 PCT/JP2014/000469 JP2014000469W WO2014132561A1 WO 2014132561 A1 WO2014132561 A1 WO 2014132561A1 JP 2014000469 W JP2014000469 W JP 2014000469W WO 2014132561 A1 WO2014132561 A1 WO 2014132561A1
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- silicon carbide
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- 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
- C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
- C30B15/14—Heating of the melt or the crystallised materials
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/90—Carbides
- C01B32/914—Carbides of single elements
- C01B32/956—Silicon carbide
- C01B32/963—Preparation from compounds containing silicon
- C01B32/97—Preparation from SiO or SiO2
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/90—Carbides
- C01B32/914—Carbides of single elements
- C01B32/956—Silicon carbide
- C01B32/963—Preparation from compounds containing silicon
- C01B32/984—Preparation from elemental silicon
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- 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
- C30B29/02—Elements
- C30B29/06—Silicon
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- 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
Definitions
- the present invention relates to a method for producing silicon carbide and silicon carbide, and more particularly to a method for producing silicon carbide and silicon carbide used for various purposes such as a raw material for an abrasive and a fired member, a raw material for semiconductor silicon carbide single crystal.
- Silicon carbide has high hardness and excellent heat resistance and wear resistance, so it is used as an abrasive, and because it has high rigidity and high thermal conductivity, it can be used as a metal in the energy and aerospace fields. They are used as changing materials, such as bearings, mechanical seals, and parts for semiconductor manufacturing equipment. Furthermore, silicon carbide has a property as a semiconductor, and a single crystal is used for power devices and the like, and is a material attracting attention.
- the first is an Atchison method in which silica sand and coke are heated by energization around a graphite electrode.
- the second is a vapor phase growth method synthesized by reaction of silane gas or methane gas.
- the third is a SiO 2 reduction method in which silica (SiO 2 ) is reduced with carbon (C) at a high temperature.
- silicon carbide by the Atchison method has a problem that the purity is not high.
- the vapor deposition method has a problem that productivity is not high.
- the reduction method causes non-uniformity of the Si to C ratio due to the accuracy of the mixing ratio of silica and carbon.
- the molar ratio of silica to carbon is determined, and detailed considerations such as the bulk density of the granular raw material and the filling rate into the container are necessary.
- any of the above methods requires high-temperature treatment, and there is a problem in terms of manufacturing costs.
- Patent Document 2 carbon is mixed with waste silicon sludge and heated (Patent Document 2), or carbide powder of silicon-integrated biomass is irradiated with high frequency (Patent Document 3), glass fiber The cost of raw materials is reduced, such as heat treatment of reinforced plastic (Patent Document 4).
- Patent Document 5 there is a technique for producing silicon carbide with high efficiency and high productivity by impregnating graphite with silane or siloxane and heating (Patent Document 5) or heating a curable silicone composition (Patent Document 6). It is disclosed. However, these techniques require dedicated energy for producing silicon carbide.
- the present invention has been made in view of the above problems, and an object thereof is to provide a method capable of producing silicon carbide that can be produced at low cost and low energy.
- the present invention provides a silicon material from a silicon melt accommodated in a container heated by the carbon material heater in a non-oxidizing atmosphere by disposing a carbon material heater in the silicon crystal production apparatus.
- Silicon carbide is produced by producing silicon carbide by forming silicon carbide on the surface of the carbon material heater, and collecting the secondary silicon carbide when producing the crystal. Provide a method.
- silicon carbide was produced at cost and energy.
- silicon carbide can be manufactured together as a by-product in the manufacture. That is, not only a silicon crystal but also silicon carbide can be manufactured at a cost and energy required for manufacturing a silicon crystal. Therefore, the cost and energy required for the production of silicon carbide can be substantially reduced to substantially zero, and silicon carbide can be produced at a much lower cost and with lower energy than in the past.
- silicon carbide can be additionally formed on the surface of another carbon member in the silicon crystal manufacturing apparatus and recovered. In this way, silicon carbide can be manufactured with higher productivity.
- the silicon crystal can be produced by a Czochralski method using a quartz crucible as a container for containing the silicon melt by flowing an inert gas into the silicon crystal production apparatus.
- the quartz crucible When the quartz crucible is used in this way, the quartz crucible is melted and oxygen is introduced into the silicon melt, and the SiO gas is evaporated from the surface of the silicon melt, so that the formation of silicon carbide by the reaction of SiO + 2C ⁇ SiC + CO easily proceeds. . Further, since carbon members generally used for silicon crystal production by the Czochralski (CZ) method are purified by high-temperature treatment or the like, the carbon members are highly pure, and the silicon carbide formed can be made highly pure. .
- CZ Czochralski
- the silicon crystal can be produced while flowing an inert gas through the silicon crystal production apparatus, passing the inert gas over the surface of the silicon melt, and then guiding it to the carbon material heater.
- an inert gas containing SiO gas or the like can be efficiently flowed to the carbon material heater through the surface of the silicon melt, silicon carbide is easily formed on the surface of the carbon material heater. .
- the furnace pressure in the silicon crystal manufacturing apparatus when manufacturing the silicon crystal can be set to 1 hPa or more and 500 hPa or less. If it does in this way, evaporation of SiO gas from a silicon melt can be accelerated
- the secondary silicon carbide formed in a powder form can be sucked and collected.
- the secondary silicon carbide formed in a layered shape or a lump shape can be peeled off and recovered. If it does in this way, recovery of silicon carbide can be performed efficiently.
- the recovered silicon carbide can be classified and pulverized. In this way, for example, silicon carbide powder having desired characteristics can be obtained for each application.
- silicon carbide manufactured by the manufacturing method of the silicon carbide of this invention Comprising:
- the nitrogen content of this silicon carbide can provide what is 0.02 mass% or less.
- the nitrogen content is 0.02% by mass or less, which is extremely low and can be highly purified.
- silicon carbide can be produced as a by-product in the production of silicon crystals without bothering the individual treatment for producing silicon carbide.
- the cost and energy required for the process can be greatly reduced, and an extremely high purity can be obtained.
- FIG. 2 shows an example of a silicon crystal production apparatus that can be used in the method for producing silicon carbide of the present invention.
- a CZ single crystal pulling apparatus is shown as an example, but the present invention is not limited to this.
- a silicon single crystal can be produced, and silicon carbide is formed on the surface of the carbon material heater as a secondary. Anything is possible.
- a CZ single crystal pulling apparatus 1 shown in FIG. 2 is a container (here crucible (quartz crucible 3, graphite crucible 4)) containing a silicon melt 2, a carbon material heater (heater for melting and melting a polycrystalline silicon raw material) A graphite heater) 5 and the like are provided in the water-cooled main chamber 6.
- a pulling mechanism (not shown) for pulling up the grown single crystal is provided on the upper portion of the pulling chamber 7 connected to the main chamber 6.
- a pulling wire 8 is unwound from a pulling mechanism attached to the upper part of the pulling chamber 7, and a seed crystal 9 supported by a seed holder is attached to the tip of the pulling wire 8.
- the silicon single crystal 10 can be formed below the seed crystal 9 by dipping in the wire 2 and winding the pulling wire 8 by a pulling mechanism.
- the quartz crucible 3 and the graphite crucible 4 are supported by a crucible rotating shaft that can be rotated and raised by a rotation drive mechanism (not shown) attached to the lower part of the CZ single crystal pulling apparatus 1.
- the carbon material heater 5 disposed around the quartz crucible 3 and the graphite crucible 4 is formed with slits alternately from the upper part and the lower part to form a path through which current flows.
- a heat insulating member (heat shield 11) formed of carbon fiber or the like is provided outside the carbon material heater 5 in order to suppress heat loss.
- the inside of the heat shield 11 is covered with a thin graphite material (inner shield 11a) in order to prevent the heat shield 11 from being deteriorated.
- an upper shield heat insulating material 16 whose inner side is covered with an upper shield 16a is disposed on the carbon material heater 5 so as to protrude from the heat shield 11 and the inner shield 11a.
- These are also formed from a carbon member such as graphite.
- a carbon member such as graphite.
- other carbon members such as the graphite crucible 4, the inner shield 11a, and the upper shield 16a are also disposed around the carbon material heater 5.
- silicon carbide 17 is formed on those surfaces as a secondary material during the production of the silicon single crystal.
- the chambers 6 and 7 are provided with a gas inlet 12 and a gas outlet 13, and an inert gas such as argon gas is introduced into the chambers 6 and 7 or is forced by using a vacuum pump or the like. It can be discharged.
- an inert gas such as argon gas
- the main chamber 6 of the CZ single crystal pulling apparatus 1 can be filled with the inert gas and, for example, controlled to be in a reduced pressure state.
- the gas rectifying cylinder 14 extends from at least the ceiling of the main chamber 6 toward the silicon melt surface so as to surround the silicon single crystal 10 being pulled up. Further, a heat shield member 15 is provided to cool the silicon single crystal 10 by blocking the radiant heat from the carbon material heater 5 between the vicinity of the surface of the silicon melt and the gas flow straightening cylinder 14.
- FIG. 1 shows an example of steps in the production method of the present invention.
- Step 1 Production of silicon crystal and secondary formation of silicon carbide
- a silicon crystal here, a silicon single crystal
- the type of the silicon crystal manufacturing apparatus is not particularly limited, but here, the case of manufacturing using the CZ single crystal pulling apparatus 1 having a quartz crucible as shown in FIG. 2 will be described. In particular, the reason why it is preferable to use such a CZ single crystal pulling apparatus 1 will be described below.
- Si + C ⁇ SiC, SiO 2 + 3C ⁇ SiC + 2CO, SiO + 2C ⁇ SiC + CO, and the like can be considered. Since the melting point of silicon is 1412 ° C. in the furnace environment temperature for growing the silicon single crystal, the maximum temperature in the furnace is about 2000 ° C. In such a temperature range, SiO + 2C ⁇ SiC + CO is most likely to occur among the above reactions.
- carbon members used for the production of silicon single crystals by the CZ method are highly purified because they are purified by high-temperature treatment or the like.
- Quartz crucibles are also highly purified, such as using synthetic quartz on the inner surface. For this reason, there is an advantage that silicon carbide by-produced at the time of manufacturing a silicon single crystal by the CZ method has a very high purity.
- a polycrystalline raw material was put into a crucible (a graphite crucible 4 on the outside and a quartz crucible 3 on the inside) and surrounded by an inner shield 11a and an upper shield 16a.
- Silicon melt 2 is obtained by heating and melting with a carbon material heater 5.
- the seed crystal 9 is dipped in the silicon melt 2 and then pulled up to produce a silicon single crystal 10 by the CZ method.
- silicon carbide 17 can be formed as a secondary.
- silicon carbide 17 can be by-produced on the surface of the carbon material heater 5 that is the highest temperature in the main chamber 6, but in addition to this, as shown in FIG. It is also possible to arrange another carbon member (graphite crucible 4, inner shield 11a, upper shield 16a, etc.) and the like and to cause silicon carbide 17 to be by-produced on the surface thereof. This is preferable because more secondary silicon carbide 17 can be obtained and productivity can be improved.
- silicon single crystal production conditions in-furnace configuration, in-furnace pressure, etc.
- silicon single crystal production conditions in-furnace configuration, in-furnace pressure, etc.
- an inert gas argon (Ar) or the like
- a gas inlet 12 is disposed in the pulling chamber
- a gas outlet 13 is disposed in the lower portion of the main chamber
- a gas rectifying cylinder 14 a heat shield member 15, an inner shield 11a, an upper shield 16a, and the like are disposed.
- the inert gas introduced from the gas inlet 12 can be caused to flow to the vicinity of the surface of the silicon melt 2 and further to the carbon material heater 5. Then, it can be discharged from the main chamber 6. In this way, the SiO gas generated from the surface of the silicon melt can be efficiently conveyed to the carbon material heater, and the reaction of SiO + 2C ⁇ SiC + CO easily proceeds on the surface of the carbon material heater.
- the inert gas from the gas outlet using a vacuum pump or the like.
- the gas that has passed over the silicon melt can be efficiently flowed to the carbon material heater, so that silicon carbide is easily formed on the surface of the carbon material heater.
- the evaporation of SiO is further promoted, and the formation of silicon carbide is further facilitated by the above-described reaction (SiO + 2C ⁇ SiC + CO).
- the evaporation amount of SiO can be effectively promoted by setting it to 500 hPa or less, and by elevating it to 1 hPa or more, elution of the quartz crucible becomes faster than necessary due to too high vacuum. Can be prevented.
- Step 2 Recovery of secondary silicon carbide
- silicon carbide is formed on the surface of the carbon material heater and the surface of the surrounding carbon member, and recovered after the production batch of the silicon single crystal is completed.
- silicon carbide is formed in a powder form, it can be recovered by suction.
- silicon carbide is best formed on the surface of the carbon material heater having the highest temperature in the furnace (in the main chamber).
- powdered silicon carbide is formed on the surface of the carbon heater or the surface of the surrounding carbon parts such as the graphite crucible. In order to efficiently recover these powdered silicon carbide, a method of sucking and recovering with a vacuum cleaner or the like is efficient.
- silicon carbide is recovered by peeling off the carbon material heater after the completion of the silicon single crystal production batch or at the end of the heater life. Good. Since the reaction of silicon carbide proceeds best on the surface of the carbon material heater having the highest temperature in the furnace, particularly, massive silicon carbide is easily formed. Since this lump-like silicon carbide is difficult to collect by suction, it is efficient to peel off the lump from the carbon material heater and collect it.
- the operation of peeling silicon carbide from the carbon material heater may be performed every time when the production batch of the silicon single crystal is finished, or may be peeled off after the lump has grown to some extent.
- the surface of the carbon material heater is increasingly silicon carbide, and the carbon part forming the slits of the carbon material heater is gradually reduced in thickness, and eventually the performance as a heater is not satisfied. Silicon carbide may be peeled off at the end of the heater life.
- the lump of silicon carbide may be peeled off with a scraper or may be peeled off by hitting with a hammer.
- the material of the tool may be an optimum material such as metal or ceramic.
- Silicon carbide powder having desired characteristics can be obtained by classifying and grinding the silicon carbide formed and recovered by the above method.
- the classification method, the pulverization method, and the like can be appropriately determined according to the use of silicon carbide.
- the in-furnace parts are generally made of carbon, silicon, and quartz, and the elements are only C, Si, and O.
- the silicon raw material is of course semiconductor grade high purity. Quartz crucibles are often made of high-purity synthetic quartz material on the inner side in contact with the silicon melt, so that high purity is maintained. Carbon members that are frequently used for in-furnace parts are purified by high-temperature treatment and have high purity. Since there are other inert gases in the furnace, other impurities are very low in concentration.
- nitrogen that is difficult to remove by conventional general methods using pitch-based carbon derived from plants and phenol resin-derived raw materials used in silicon carbide production can be kept at a very low concentration in the present invention, and the nitrogen content
- the amount can be, for example, 0.02% by mass or less.
- the crystal system is mainly 3C type ( ⁇ type).
- the Si: C ratio is almost 1: 1 and high quality.
- Pure silicon carbide is obtained.
- Those obtained by pulverizing them to a desired size can be used not only as abrasives but also as ultra-high grades such as raw materials and seed crystals for producing silicon carbide semiconductor single crystals.
- silicon carbide can be produced as a byproduct of silicon single crystal production, rather than producing silicon carbide alone. And the cost and energy accompanying silicon carbide manufacture can be reduced extremely.
- Example 1 The manufacturing method of the silicon carbide of this invention shown in FIG. 1 was implemented. A silicon single crystal was grown using the CZ single crystal pulling apparatus 1 shown in FIG.
- the carbon material heater used the heater with the outer diameter of about 800 mm formed with the graphite material.
- a heat insulating material (heat shield) made of carbon fiber is placed inside the water-cooled main chamber to suppress heat loss, and the inside of the heat insulating material is thin graphite to prevent deterioration of the heat insulating material. Covered with material (inner shield).
- an upper shield heat insulating material and an upper shield formed of the graphite material on the surface thereof were arranged so as to protrude from the heat shield and the inner shield.
- a graphite crucible (inner diameter is about 660 mm) is provided on the outside of the container, and a crucible made of a quartz crucible in which synthetic quartz is formed inside natural quartz is used on the inside of the container.
- the gas containing SiO discharged from the crucible flows toward the gas outlet through the gas induction path formed by the outer wall of the graphite crucible, the lower part of the upper shield, and the inner wall part of the inner shield. Since there is a graphite heater in the gas induction path formed by the graphite crucible, the upper shield, and the inner shield, the silicon carbide reaction occurs here. Although the silicon carbide reaction occurs most frequently in the heater having the highest temperature, the silicon carbide reaction occurs also on the outer wall of the surrounding graphite crucible, the lower part of the upper shield, and the inner wall part of the inner shield.
- a silicon single crystal having a diameter of about 200 mm was grown under the above conditions.
- One or more silicon single crystals were grown in one batch.
- silicon carbide could be formed on the surface of a graphite member such as a graphite heater, a graphite crucible, an inner shield, and an upper shield as a secondary component during the production of a silicon single crystal.
- a graphite member such as a graphite heater, a graphite crucible, an inner shield, and an upper shield.
- silicon carbide obtained by the present invention was analyzed.
- the recovered silicon carbide powder was subjected to microscopic Raman analysis, a steep peak was observed at 795 cm ⁇ 1 . Further, the obtained powder had a very beautiful yellow color, and very high purity 3C type ( ⁇ type) silicon carbide was obtained.
- oxygen analysis was performed using an oxygen analyzer (manufactured by LECO, trade name: TC436), the oxygen content was 0.1% by mass or less, and the nitrogen content was 0.00% by mass. . Since the nitrogen content of silicon carbide produced using a phenol resin is about 0.2% by mass as in the prior art, it can be seen that the nitrogen content of silicon carbide according to the present invention is very low.
- Example 2 The same production batch as in Example 1 was repeated. As a result, silicon carbide of the graphite heater progressed, and the graphite portion forming the slits gradually decreased in thickness, and a lump of silicon carbide was formed until the graphite heater performance was not satisfied. The silicon carbide deposited on the graphite heater whose heater life was completed was recovered by peeling off the graphite heater. The yellow-green silicon carbide crystal recovered in this manner was about 3.1 kg.
- Example 2 since the state of the 13C nucleus is close to a single state, the signal intensity is detected to be larger than that of a commercially available product.
- the silicon carbide of the present invention has a sharper peak and better crystallinity than commercially available silicon carbide powder in which a crystal system such as 6H type is mixed.
- Example 1 utilization of the silicon carbide powder manufactured in Example 1 or Example 2 was tried.
- 100 parts by mass of the obtained silicon carbide powder and 3 parts by mass of methylcellulose (trade name: Metroles, manufactured by Shin-Etsu Chemical Co., Ltd.) as an organic binder were combined with planetary ball mill P-4 type (registered trademark) (Fritsch Japan Co., Ltd.).
- the mixture was placed in a container of a pulverized mixer) and mixed at room temperature for 1 hour.
- 20 parts by mass of water was added to the obtained mixed powder, and the mixture was put into a planetary mixer (registered trademark) (mixer manufactured by Inoue Seisakusho Co., Ltd.) and stirred at room temperature for 1 hour to obtain a clay.
- the kneaded material was heated at 105 ° C. for 5 hours to evaporate water, and a powdery raw material composition was obtained.
- This raw material composition was put into a mold and pressed at a pressure of 100 kgf / cm 2 for 5 minutes to obtain a cylindrical molded product having a diameter of 110 mm and a thickness of 82 mm. Further, this molded product was put into a rubber mold and Dr. of the CIP molding machine. Pressing was performed for 1 hour at a pressure of 2000 kgf / cm 2 using CIP (registered trademark) (manufactured by Kobe Steel). The dimensions after CIP molding were 108 mm diameter x 80 mm thickness.
- a black inorganic molded product substantially consisting of carbon, silicon and oxygen was obtained.
- the inorganic molded product had a diameter of 108 mm and a thickness of 80 mm, and the shape was almost the same as that before the heat treatment.
- this inorganic molded product was heated to 2000 ° C. in an argon gas atmosphere, heated at 2000 ° C. and then cooled to obtain a green silicon carbide molded product.
- the silicon carbide molded product had a diameter of 108 mm and a thickness of 80 mm, and the shape was almost the same as that of the inorganic molded product.
- this silicon carbide molding was used as a raw material for silicon carbide growth using a sublimation method, a single crystal could be produced.
- silicon carbide powder obtained in the present invention a commercially available silicon carbide powder (trade name: Shinano Random, manufactured by Shinano Denki Co., Ltd.) is used instead.
- a raw material composition was prepared in the same manner as in the method, and this was press-molded and subjected to CIP molding, followed by degreasing and firing. As a result, it was in a fine powder state and did not retain its shape.
- Silicon carbide was manufactured by the conventional manufacturing method described in Patent Document 5.
- Expanded graphite was added to the solution dissolved in the solution, dried in a vacuum oven at 100 ° C. for about 30 minutes, and then heated and cured at 300 ° C. in the air for 1 hour. This was heated to 1600 ° C. at a rate of temperature increase of about 300 K / hr in an argon stream, held for 1 hour, and then cooled at a rate of about 200 K / hr to obtain a grayish white product.
- the present invention is not limited to the above embodiment.
- the above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.
- the present invention is not limited to the production of a single crystal. Even when a polycrystal is grown in a similar apparatus configuration such as for a solar cell, the same silicon carbide as in the case of growing a silicon single crystal can be produced, and this case is also included in the technical scope of the present invention. .
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Abstract
Description
1つ目は、珪砂とコークスを黒鉛電極の周りにおいて通電加熱するアチソン法である。また2つ目は、シランガスやメタンガスの反応によって合成する気相成長法である。さらに3つ目は、シリカ(SiO2)を炭素(C)によって高温で還元するSiO2還元法である。
そこで炭化珪素の製造コストの削減のため、廃シリコンスラッジに炭素を混合して加熱したり(特許文献2)、珪素集積バイオマスの炭化物粉体に高周波を照射したり(特許文献3)、ガラス繊維強化プラスチックを加熱処理する(特許文献4)など、原料の低コスト化を図っている。
しかしながら、これらの技術は炭化珪素を製造するための専用のエネルギーが必要である。
しかしながら、上記本発明の製造方法であれば、シリコン結晶を製造するとともに、その製造での副生成物として炭化珪素を併せて製造することができる。すなわち、シリコン結晶を製造するのに必要なコスト、エネルギーで、シリコン結晶のみならず炭化珪素までも製造することができる。したがって、炭化珪素の製造に要するコスト、エネルギーは、実質上、基本的にはゼロ近くにすることができ、従来よりも極めて低コスト、低エネルギーで炭化珪素を製造できる。
このようにすれば、より生産性高く炭化珪素を製造することができる。
また、一般にチョクラルスキー(CZ)法によるシリコン結晶製造に用いられる炭素部材は高温処理などによって純化処理してあるので高純度であり、形成される炭化珪素も高純度のものにすることができる。
このようにすれば、前記シリコンメルトの表面上を通過してSiOガス等を含む不活性ガスを炭素材ヒーターへ効率よく流すことができるので、炭素材ヒーターの表面において炭化珪素が形成されやすくなる。
このようにすれば、シリコンメルトからのSiOガスの蒸発を促進することができ、炭化珪素の形成を進みやすくすることができる。
また、前記シリコン結晶の製造バッチ終了後または前記炭素材ヒーターのライフ末期に、層状または塊状に形成された前記副次的な炭化珪素を剥がして回収することができる。
これらのようにすれば、効率良く炭化珪素の回収を行うことができる。
このようにすれば、例えば用途別に、所望の特性を有する炭化珪素粉を得ることができる。
このように、本発明の方法で製造した炭化珪素においては、窒素含有量が0.02質量%以下で極めて低く、高純度のものとすることができる。
図2に本発明の炭化珪素の製造方法において使用することができるシリコン結晶製造装置の一例を示す。ここでは、その例としてCZ単結晶引上げ装置を示すが、当然これに限定されるものではなく、シリコン単結晶を製造することができ、かつ副次的に炭素材ヒーターの表面に炭化珪素を形成できるものであれば良い。
また、該炭素材ヒーター5の外側には、熱ロスを抑えるために炭素繊維等で形成された断熱部材(ヒートシールド11)が設けられている。また、ヒートシールド11の内側は、ヒートシールド11の劣化を防止するために薄い黒鉛材(インナーシールド11a)で覆っている。
また、炭素材ヒーター5の上部にはヒートシールド11およびインナーシールド11aからせり出すように、内側がアッパーシールド16aで覆われたアッパーシールド断熱材16が配設されている。これらも黒鉛等の炭素部材から形成されている。
このように、炭素材ヒーター5の周囲には、黒鉛ルツボ4、インナーシールド11a、アッパーシールド16aなどの、他の炭素部材も配置されている。そして、それらの表面には、シリコン単結晶の製造時に副次的に炭化珪素17が形成される。
(工程1:シリコン結晶の製造および炭化珪素の副次的な形成)
まず、内部に炭素材ヒーターを配設したシリコン結晶製造装置を用いて、非酸化性雰囲気下でシリコンメルトからシリコン結晶(ここではシリコン単結晶)を製造する。前述したように、このシリコン結晶製造装置の種類は特に限定されないが、ここでは図2に示すような石英ルツボを有するCZ単結晶引上げ装置1を用いて製造する場合について説明する。
特には、このようなCZ単結晶引上げ装置1を用いるのが好ましい理由について以下に述べる。
まず、不活性ガス(アルゴン(Ar)等)をメインチャンバ内に流し、シリコンメルトの表面上を通過させ、その後に炭素材ヒーターへ導入するようなガス誘導経路を形成させることが好ましい。図2に示すように、引上げチャンバにガス導入口12、メインチャンバの下部にガス流出口13、さらにはガス整流筒14および遮熱部材15、インナーシールド11a、アッパーシールド16aなどを配設することにより、ガス導入口12から導入した不活性ガスをシリコンメルト2の表面近傍にまで流し、さらには炭素材ヒーター5にまで誘導することができる。そして、その後はメインチャンバ6から排出することができる。
このようにすればシリコンメルトの表面から発生したSiOガスを効率よく炭素材ヒーターに運ぶことができ、炭素材ヒーター表面でSiO+2C→SiC+COの反応が進みやすくなる。
更に減圧状態に保つことによりSiOの蒸発が一層促進され、上述の反応(SiO+2C→SiC+CO)によって炭化珪素の形成が一層進みやすくなる。このとき、特には、500hPa以下とすることにより、SiOの蒸発量を効果的に促進することができるし、1hPa以上とすることにより、高真空すぎて石英ルツボの溶出が必要以上に速くなるのを防ぐことができる。
以上のようにして、炭化珪素を炭素材ヒーターの表面及び周辺の炭素部材の表面に形成させ、シリコン単結晶の製造バッチ終了後に回収する。炭化珪素が粉状に形成されている場合は、吸引して回収することができる。
上述のシリコン単結晶製造において、前述したように炉内(メインチャンバ内)で最も高温である炭素材ヒーターの表面には炭化珪素が最も良く形成される。炭素ヒーターの表面や、それ以外にも黒鉛ルツボなど周囲にある炭素部品の表面には、例えば粉状の炭化珪素が形成される。これら粉状の炭化珪素を効率よく回収するには真空掃除機等のようなものにより吸引回収する方法が効率的である。
炉内で最も高温である炭素材ヒーター表面では炭化珪素の反応が最も良く進むので、特に塊状の炭化珪素が形成されやすい。この塊状の炭化珪素は吸引によっては回収しにくいので、塊ごと炭素材ヒーターから剥がして回収することが効率的である。炭素材ヒーターから炭化珪素を剥がす作業は、シリコン単結晶の製造バッチが終了した際に毎回行っても良いし、ある程度塊が大きくなってからまとめて剥がしても良い。
以上の方法で形成、回収された炭化珪素を分類し、粉砕することにより所望の特性を持つ炭化珪素粉にすることができる。分類の仕方や粉砕方法等は、炭化珪素の用途等に応じて適宜決定することができる。
回収された炭化珪素は、例えばCZ単結晶引上げ装置内で生成されたものの場合、この炉内部品は一般に炭素、シリコン、石英からなり、元素としてはC、Si、Oだけである。シリコン原料はもちろん半導体グレードの高純度である。石英ルツボもシリコンメルトと接する内側に純度の高い合成石英材を用いることが多く、高純度が保たれている。炉内部品に多用される炭素部材は高温処理によって純化処理してあり高純度である。炉内にはこのほか不活性ガスがあるだけなので、その他の不純物はきわめて低濃度である。
(実施例1)
図1に示す本発明の炭化珪素の製造方法を実施した。図2に示したCZ単結晶引上げ装置1を用いてシリコン単結晶を育成した。
なお、炭素材ヒーターには黒鉛材で形成した外径約800mmのヒーターを用いた。また、水冷されたメインチャンバより内側には、熱ロスを抑えるために炭素繊維で形成された断熱材(ヒートシールド)を配置し、断熱材の内側は断熱材の劣化を防止するため、薄い黒鉛材(インナーシールド)で覆っている。また、黒鉛ヒーターの上部には、アッパーシールド断熱材およびその表面の黒鉛材で形成されたアッパーシールドを、ヒートシールドやインナーシールドからせり出すように配置した。
シリコンメルトを収容する容器としては、容器外側が黒鉛ルツボ(内径が約660mm)であり、容器内側には、天然石英の内側に合成石英を形成した石英ルツボからなるルツボを用いた。
そして実際に、シリコン単結晶製造の際、副次的に、黒鉛ヒーター、黒鉛ルツボ、インナーシールド、アッパーシールドなどの黒鉛部材の表面に炭化珪素を形成することができた。
バッチが終了するたびに、この副次的な炭化珪素を真空掃除機によって回収することにより、炭化珪素を得ることができた。
シリコン単結晶の製造と併せて炭化珪素を製造することができるのでコストやエネルギーを低減することができた。
まず、回収された炭化珪素粉を顕微ラマン解析したところ、795cm-1に急峻なピークが見られた。また得られた粉は非常にきれいな黄色をしており、非常に高純度な3C型(β型)の炭化珪素が得られた。
また酸素分析装置(LECO社製、商品名:TC436)を用いて、酸素分析を行ったところ、酸素の含有量は0.1質量%以下、窒素の含有量は0.00質量%であった。従来のように、フェノール樹脂を用いて製造された炭化珪素の窒素含有量は0.2質量%程度であるので、本発明による炭化珪素の窒素含有量が非常に低いことがわかる。元素比は(Si:C=1:1.00)であり、非常に結晶性の良い物であった。
実施例1と同様の製造バッチを繰り返した。これにより黒鉛ヒーターの炭化珪素化が進行し、スリットを形成している黒鉛部分がどんどん減肉し、黒鉛ヒーターとしての性能を満たさなくなるまで炭化珪素の塊を形成した。
そしてヒーターライフの終了した黒鉛ヒーターに堆積していた炭化珪素を黒鉛ヒーターから剥がすことにより回収した。これにより回収された黄緑色の炭化珪素結晶は約3.1kgであった。
この図3から分かるように、本発明の炭化珪素は、6H型など結晶系が混在している市販の炭化珪素粉に比較してピークが鋭く結晶性が良いことがわかる。
更にICP発光分析に供したところ、種々の元素の含有量について表1に示す結果が得られた。表1に示すように、Caが0.1ppm、その他Fe等は0.1ppm未満であり、不純物の割合が極めて少なく、非常に高純度の炭化珪素が得られたことが判る。
まず、得られた炭化珪素粉末100質量部と有機バインダとしてメチルセルロース(商品名:メトローズ、信越化学工業株式会社製)3質量部とを遊星型ボールミルP-4型(登録商標)(フリッチュジャパン株式会社製の粉砕混合機)の容器に入れ、室温にて一時間混合を行った。得られた混合粉に水20質量部を加え、混合物をプラネタリーミキサー(登録商標)(井上製作所株式会社製の混合機)に投入し、室温にて一時間攪拌して坏土を得た。その後、該坏土を105℃で5時間に渡って加熱し水分を蒸発させ、粉末状の原料組成物を得た。
次に、この無機成形物をアルゴンガス雰囲気下で加熱して2000℃まで昇温し、その2000℃において加熱した後に冷却したところ、緑色の炭化珪素成形物を得た。この炭化珪素成形物の寸法は直径108mm×厚さ80mmであり、形状は上記無機成形物とほとんど同じ形状であった。
そして、この炭化珪素成形物を、昇華法を用いた炭化珪素育成用の原料として用いたところ、単結晶を製造することが出来た。
特許文献5に記載の従来の製法によって炭化珪素を製造した。
テトラメチルテトラビニルシクロテトラシロキサン(信越化学工業株式会社製LS-8670)にメチル水素シロキサン(信越化学工業株式会社製KF-99)及び塩化白金酸触媒(塩化白金酸1%溶液)の混合物をトルエンに溶解した溶液に膨張黒鉛を加えて、真空オーブン中100℃で約30分乾燥後、大気中300℃で1時間加熱硬化した。このものをアルゴン気流中で、約300K/hrの昇温速度で1600℃まで昇温して、1時間保持後、約200K/hrの速度で冷却したところ、灰白色を呈する生成物を得た。
また、本来、高純度の3C型(β型)の炭化珪素は黄色であるが、比較例で得られた炭化珪素が灰白色であるということは酸素が残存していることを示唆している。従って実施例1、実施例2のような本発明によって得られた炭化珪素の方が優れた品質であることが明確である。
Claims (9)
- シリコン結晶製造装置内に炭素材ヒーターを配設し、非酸化性雰囲気下で前記炭素材ヒーターにより加熱された容器内に収容されたシリコンメルトからシリコン結晶を製造するとき、副次的に、前記炭素材ヒーターの表面に炭化珪素を形成させ、該副次的な炭化珪素を回収することにより炭化珪素を製造することを特徴とする炭化珪素の製造方法。
- 前記シリコン結晶を製造するとき、さらに、前記シリコン結晶製造装置内の他の炭素部材の表面にも炭化珪素を副次的に形成させて回収することを特徴とする請求項1に記載の炭化珪素の製造方法。
- 前記シリコン結晶製造装置内に不活性ガスを流し、前記シリコンメルトを収容する容器として石英ルツボを用いたチョクラルスキー法によって前記シリコン結晶を製造することを特徴とする請求項1または請求項2に記載の炭化珪素の製造方法。
- 前記シリコン結晶製造装置内に不活性ガスを流し、該不活性ガスを、前記シリコンメルトの表面上を通過させた後に前記炭素材ヒーターへ導きながら前記シリコン結晶を製造することを特徴とする請求項1から請求項3のいずれか一項に記載の炭化珪素の製造方法。
- 前記シリコン結晶を製造するときの前記シリコン結晶製造装置内の炉内圧を1hPa以上500hPa以下とすることを特徴とする請求項1から請求項4のいずれか一項に記載の炭化珪素の製造方法。
- 前記シリコン結晶の製造バッチ終了後、粉状に形成された前記副次的な炭化珪素を吸引回収することを特徴とする請求項1から請求項5のいずれか一項に記載の炭化珪素の製造方法。
- 前記シリコン結晶の製造バッチ終了後または前記炭素材ヒーターのライフ末期に、層状または塊状に形成された前記副次的な炭化珪素を剥がして回収することを特徴とする請求項1から請求項6のいずれか一項に記載の炭化珪素の製造方法。
- 前記回収した炭化珪素を分類して粉砕することを特徴とする請求項1から請求項7のいずれか一項に記載の炭化珪素の製造方法。
- 請求項1から請求項8のいずれか一項に記載の炭化珪素の製造方法により製造された炭化珪素であって、該炭化珪素の窒素含有量が0.02質量%以下であることを特徴とする炭化珪素。
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Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003002780A (ja) * | 2001-04-20 | 2003-01-08 | Shin Etsu Handotai Co Ltd | シリコン単結晶の製造装置及びそれを用いたシリコン単結晶の製造方法 |
JP2008087997A (ja) * | 2006-09-29 | 2008-04-17 | Sumco Techxiv株式会社 | シリコン単結晶引上げ装置及び該装置に使用される黒鉛部材並びに黒鉛部材の劣化防止方法 |
JP2010042955A (ja) * | 2008-08-12 | 2010-02-25 | Air Water Hydrogen Corp | 単結晶引上装置における不活性ガス回収装置 |
JP2011032109A (ja) * | 2009-07-30 | 2011-02-17 | Nippon Steel Corp | 炭化珪素単結晶製造装置 |
JP2012012271A (ja) * | 2010-07-05 | 2012-01-19 | Shin Etsu Handotai Co Ltd | 黒鉛ルツボ |
CN102728582A (zh) * | 2012-07-06 | 2012-10-17 | 宁夏隆基硅材料有限公司 | 一种直拉法生长单晶硅用石墨件的清洗方法 |
JP2013147406A (ja) * | 2012-01-23 | 2013-08-01 | Shin Etsu Handotai Co Ltd | シリコン単結晶の製造方法 |
-
2013
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- 2014-01-30 WO PCT/JP2014/000469 patent/WO2014132561A1/ja active Application Filing
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- 2014-01-30 KR KR1020157022660A patent/KR20150123806A/ko active Search and Examination
- 2014-01-30 DE DE112014000677.7T patent/DE112014000677T5/de not_active Withdrawn
- 2014-01-30 CN CN201480010278.5A patent/CN105008278A/zh active Pending
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003002780A (ja) * | 2001-04-20 | 2003-01-08 | Shin Etsu Handotai Co Ltd | シリコン単結晶の製造装置及びそれを用いたシリコン単結晶の製造方法 |
JP2008087997A (ja) * | 2006-09-29 | 2008-04-17 | Sumco Techxiv株式会社 | シリコン単結晶引上げ装置及び該装置に使用される黒鉛部材並びに黒鉛部材の劣化防止方法 |
JP2010042955A (ja) * | 2008-08-12 | 2010-02-25 | Air Water Hydrogen Corp | 単結晶引上装置における不活性ガス回収装置 |
JP2011032109A (ja) * | 2009-07-30 | 2011-02-17 | Nippon Steel Corp | 炭化珪素単結晶製造装置 |
JP2012012271A (ja) * | 2010-07-05 | 2012-01-19 | Shin Etsu Handotai Co Ltd | 黒鉛ルツボ |
JP2013147406A (ja) * | 2012-01-23 | 2013-08-01 | Shin Etsu Handotai Co Ltd | シリコン単結晶の製造方法 |
CN102728582A (zh) * | 2012-07-06 | 2012-10-17 | 宁夏隆基硅材料有限公司 | 一种直拉法生长单晶硅用石墨件的清洗方法 |
Non-Patent Citations (1)
Title |
---|
TETSUO FUKUDA ET AL.: "A Czochralski silicon growth technique which reduces carbon to the order of 1014 per cubic centimeter", JOURNAL OF THE ELECTROCHEMICAL SOCIETY, vol. 141, no. 8, August 1994 (1994-08-01), pages 2216 - 2220, XP000471077 * |
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