| 摘要 |
PURPOSE:To perform the trimming on the crystal defective part generated on a layer formed by vapor growth very easily when compared with the method heretofore in use by a method wherein the impurities having the conductivity type opposite to that of a semiconductor layer are selectively diffused on the crystal defective part. CONSTITUTION:An N<-> drain layer 12 is formed on an N<+> silicon substrate 11, P<+> gate 13 and a gate electrode 13 are selectively diffused on the surface of the layer 12, a P<+> gate 13 is formed into an N-type source layer 14 by vapor growth, and an oxide film 15 is formed on the surface of the layer 14. As the presence of a laminar defect A impairs the withstand voltage between a source and a gate, an aperture is selectively formed on the defective part A on an oxide film 15 by performing a photolithographic technique using a spot exposing machine and a positive resist immediately after a gate electrode 13 has been formed, and the P<+> layer 16, having the conductive type opposite to that of the source layer 14, is diffused. Accordingly, the defect A of a regular triangular pyramid, confined in the source N-layer 14 by a P<+> layer 16, is present in an isolated state. In this case, as the defect is isolated by the deposition layer of P<+>N junction, the adverse effect on the withstand voltage is alleviated.
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