High purity carbonaceous material and ceramic coated high purity carbonaceous material

• US 20050079359A1
• Filed: 10/06/2004
• Published: 04/14/2005
• Est. Priority Date: 10/10/2003
• Status: Active Grant

• Current Assignee: TOYO Tanso Company Limited
• Original Assignee: TOYO Tanso Company Limited
• Inventors: Nogami, Satoru, Fujita, Ichiro
• Granted Patent: US 7,517,516 B2
• Time in Patent Office: Days
• US Class Current: 428/408
• CPC Class Codes: C01P 2006/80 Compositional purity
• CPC Class Codes: C04B 2235/658 Atmosphere during thermal treatment
• CPC Class Codes: C04B 2235/6581 Total pressure below 1 atmosphere, e.g. vacuum
• CPC Class Codes: C04B 2235/6582 Hydrogen containing atmosphere
• CPC Class Codes: C04B 2235/661 Multi-step sintering
• CPC Class Codes: C04B 2235/72 Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics
• CPC Class Codes: C04B 2235/722 Nitrogen content
• CPC Class Codes: C04B 2235/723 Oxygen content
• CPC Class Codes: C04B 2235/724 Halogenide content
• CPC Class Codes: C04B 2235/726 Sulfur content
• CPC Class Codes: C04B 2235/727 Phosphorus or phosphorus compound content
• CPC Class Codes: C04B 35/522 Graphite C04B35/536 takes precedence
• CPC Class Codes: C04B 35/536 based on expanded graphite or complexed graphite
• CPC Class Codes: C04B 35/64 Burning or sintering processes C04B33/32 takes precedence ; powder metallurgy B22F
• CPC Class Codes: C04B 35/83 Carbon fibres in a carbon matrix
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/4531 by C.V.D.
• CPC Class Codes: C04B 41/5059 Silicon carbide
• CPC Class Codes: C04B 41/87 Ceramics
• CPC Class Codes: C30B 29/36 Carbides
• CPC Class Codes: C30B 35/00 : Apparatus not otherwise provided for, specially adapted for the growth, production or after-treatment of single crystals or of a homogeneous polycrystalline material with defined structure
• CPC Class Codes: Y10T 428/2918 : including free carbon or carbide or therewith [not as steel]
• CPC Class Codes: Y10T 428/30 : Self-sustaining carbon mass or layer with impregnant or other layer
• CPC Class Codes: Y10T 428/31504 : Composite [nonstructural laminate]

Abstract

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 1×10¹⁸ atoms/cm³ or less as determined by SIMS. Its chlorine content is preferably 1×10¹⁶ atoms/cm³ or less as determined by SIMS, and its nitrogen content is preferably 5×10¹⁸ atoms/cm³ 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.

Claims

1. A high purity carbonaceous material having an oxygen content of 1×

10¹⁸ atoms/cm³ or less as determined by SIMS.

2. A high purity carbonaceous material according to claim 1 which has a chlorine content of 1×

10¹⁶ atoms/cm³ or less as determined by SIMS.

3. A high purity carbonaceous material according to claim 1 or 2 which has a nitrogen content of 5×

10¹⁸ atoms/cm³ or less as determined by SIMS.

4. A high purity carbonaceous material according to any of claims 1 to 3 which has a phosphorus content of 1×

10¹⁶ atoms/cm³ or less as determined by SIMS.

5. A high purity carbonaceous material according to any of claims 1 to 4 which has a sulfur content of not higher than 1×

10¹⁶ atoms/cm³ as determined by SIMS.

6. A high purity carbonaceous material according to any of claims 1 to 5 which has a boron content of 5×

10¹⁶ atoms/cm³ or less as determined by SIMS.

9. A high purity carbonaceous material according to any of claims 1 to 8 which is intended to be used in the production of silicon carbide single crystals, silicon single crystals, gallium nitride single crystals or calcium fluoride single crystals.

10. A high purity carbonaceous material according to any of claims 1 to 8 which is intended to be used as tools or utensils in epitaxial growing of silicon carbide, gallium nitride or silicon.

11. A high purity carbonaceous material according to any of claims 1 to 8 which is intended to be used as a substrate for coating with a ceramic layer.

12. A ceramic layer-coated high purity carbonaceous material comprising a high purity carbonaceous material according to any of claims 1 to 8 as a substrate of ceramics coating.

7. A high purity carbonaceous material having a nitrogen content of not higher than 1×

10¹⁶ atoms/cm³ as determined by SIMS.

8. A high. purity carbonaceous material according to claim 7 which has a nitrogen content of 5×

10¹⁸ atoms/cm³ or less as determined by SIMS.