| 摘要 |
1,227,851. Silicon coated with oxide and nitride. WESTINGHOUSE ELECTRIC CORP. 6 Feb., 1968 [16 Feb., 1967], No. 5804/68. Heading C1A. [Also in Division H1] A semi-conductor structure includes a semiconductor, e.g. silicon body at least part of which is coated with a layer of dioxide overlain by nitride or by a mixture of dioxide and nitride. The nitride layer is produced by reacting ammonia with a silane or halosilane or preferably with a silicohalide such as silicon tetrachloride in a flow of hydrogen or argon with the substrate held at 650-1300‹ C., while a mixed layer is formed by adding oxygen to the reactant gases. In both cases the velocity of the gas flow over the substrate should exceed 8 cm./ sec. and the partial pressure of the gaseous silicon compound in the mixture should be less than 1%. The underlying oxide layer is preferably produced by oxidation of silane carried in a flow of argon with the silicon body held at 850‹ C. A preetching of the silicon body at 1140‹ C. in a mixture of hydrogen and hydrogen chloride is desirable. Suitable thicknesses of the layers which can be used for surface passivation, as diffusion masks or as the gate insulation in a P-type silicon IGFET are 30-150 Š for the oxide and 1000 Š for the nitride. The effects of varying the reaction mixture and flow rate and the substrate temperature on the rate of formation and character of the films are discussed at length in the Specification as are the properties of metal-insulator-capacitors with nitride, oxide and composite insulator layers. Reference has been directed by the Comptroller to Specification 1,130,138. |
