High purity carbonaceous material and ceramic coated high purity carbonaceous material
The invention provides a high purity carbonaceous material which is reduced in contents of oxygen, nitrogen and chlorine readily binding to carbon atoms and in contents of elements, phosphorus, sulfur and boron, readily binding to carbon atoms upon heating and which can be used in producing single crystals such as semiconductors, a high purity carbonaceous material for use as a substrate for ceramic layer coating, and a ceramic layer-coated high purity carbonaceous material. The high purity carbonaceous material has oxygen content of 1×10 18 atoms/cm 3 or less as determined by SIMS. Its chlorine content is preferably 1×10 16 atoms/cm 3 or less as determined by SIMS, and its nitrogen content is preferably 5×10 18 atoms/cm 3 or less as determined by SIMS. Its phosphorus, sulfur and boron contents are preferably not higher than respective specified values. Such a high purity carbonaceous material is coated with ceramic layer.
1. A high purity carbon material which is graphite or carbon fiber reinforced carbon composite having an oxygen content of 1×10 18 atoms/cm 3 or less as determined by SIMS.
2. A high purity carbon material according to claim 1 which has a chlorine content of 10 16 atoms/cm 3 or less as determined by SIMS.
3. A high purity carbon material according to claim 1 or 2 which has a nitrogen content of 5×10 18 atoms/cm 3 or less as determined by SIMS.
4. A high purity carbon material according to claim 1 or 2 which has a phosphorus content of 1×10 16 atoms/cm 3 or less as determined by SIMS.
5. A high purity carbon material according to claim 1 or 2 which has a sulfur content of not higher than 1×10 16 atoms/cm 3 as determined by SIMS.
6. A high purity carbon material according to claim 1 or 2 which has a boron content of 5×10 16 atoms/cm 3 or less as determined by SIMS.
7. A high purity carbon material which is graphite or carbon fiber reinforced carbon composite having a boron content of not higher than 1×10 16 atoms/cm 3 as determined by SIMS and a nitrogen content of 5×10 18 atoms/cm 3 or less as determined by SIMS.
8. A ceramic layer-coated high purity carbon material comprising a high purity carbon material according to claim 1 or 7 as a substrate of ceramics coating.
9. A method of preparing a ceramic-coated substrate comprising coating the high purity carbon material according to claim 1 or 7 with a ceramic coating.
10. A method of preventing crystal defects during the manufacture of silicon carbide single crystals, silicon single crystals, gallium nitride single crystals or calcium fluoride single crystals comprising employing the high purity carbon material according to claim 1 or 7 in the manufacture of said crystals.
11. A method of manufacturing silicon carbide, gallium nitride or silicon, comprising epitaxial growing silicon carbide, gallium nitride or silicon in the presence of the high purity carbon material according to claim 1 or 7 .