| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve a problem wherein a well region in which an insulated gate type semiconductor element is formed is a diffusion region, the impurity concentration thereof is reduced toward its bottom part, and resistance is increased, and thereby on-resistance is increased particularly in an insulated gate type semiconductor element of an up-drain structure. <P>SOLUTION: A p type well region is formed by stacking two p type impurity regions on each other. The respective p type impurity regions are allowed to serve as the p type well region by sequentially stacking n type semiconductor layers, on one another, having p type impurities implanted into their surfaces and simultaneously diffusing the impurities by heat treatment. Thereby, it is possible to obtain the p type well region in which an impurity concentration sufficient to secure a desired breakdown voltage is maintained approximately uniform up to a desired depth. <P>COPYRIGHT: (C)2010,JPO&INPIT |
