| 摘要 |
1,206,500. Silicon carbide. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 22 Oct., 1968 [23 Oct., 1967], No. 50008/68. Heading C1A. Crystalline silicon carbide is prepared by decomposing a gas mixture consisting of a hydrocarbon, e.g. propane, a silane, e.g. monosilane SiH 4 , a carrier gas, e.g. hydrogen or argon, and hydrogen chloride, the concentration of silicon atoms in the gas mixture being between 10 and 50% of the concentration of carbon atoms. The reaction may be carried out in a device as shown in the diagram which comprises a hermetically-sealed, quartz reaction vessel 19 containing a filter 18, a heating carrer 20 and a substrate 21 on which a SiC layer may be formed. If the substrate is monocrystalline, the layer will also be monocrystalline. The reaction gases, together with any auxiliary gases such as air and nitrogen are admitted through valves 1-5 and 9 and flow meters 11-15. The system may be exhausted by means of a pump connected at G or the gases allowed to pass to a burner connected at H, and the pressure throughout the system may be read on a Bourdon pressure gauge 17. The decomposition is preferably carried out at a tem. perature of between 1100‹ and 1300‹ C. and the composition of the gas mixture employed is varied according to the carrier gas used. |
