SEMICONDUCTOR DEVICE OF HIGH WITHSTAND VOLTAGE AND ITS MANUFACTURE

摘要

PROBLEM TO BE SOLVED: To provide a semiconductor device of high withstand voltage which exhibits excellent on-voltage and yield voltage and high-speed switching characteristics by realizing a micro pn repeating structure of the order of micron with an enough precision. SOLUTION: N type diffusion areas 1 and p type diffusion areas 2 are formed in areas sandwiched between slots 73 arranged on a first major surface of a semiconductor substrate. P type wells 3 are formed on the n type and p type diffusion areas 1 and 2 on the side of the first major surface. Source n<+> diffusion areas 5 are formed on the first major surface in the p type wells 3. Gate insulating layers 9 are formed which are opposed through gate insulating layers 8 in the p type wells 3 sandwiched between the n type diffusion areas 1 and the source n<+> diffusion area 5. The n type and the p type diffusion areas 1 and 2 are provided with density distribution of impurities diffused from the side walls of their slots 7a.