| 摘要 |
PURPOSE:To obtain tolerance to blooming, a smear, etc., while increasing source- drain dielectric strength, by forming a P type layer on an N type substrate and forming an N channel MOS type semiconductor device in the P type layer, and making the P type layer of the lower part of its drain deeper than any other part and increasing the density. CONSTITUTION:The density and depth of the P well 2 of the lower part 2A of the drain 7 are increased and the P well 2 of the lower part 2B of a source 6 is shallow and has excellent spectral characteristics. Those are formed by ion implantation into the N type silicon substrate 1 twice or employing ion implantation and epitaxial growth in combination. This constitution has the sufficiently high source-drain dielectric strength and excellent spectral characteristics and is tolerant to blooming, a smear, etc. |
