| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem of a conventional semiconductor device that electric field relaxation cannot be achieved easily in a drain region when the drain region is formed of a DDD structure by thinning a gate oxide film. SOLUTION: In a method for manufacturing a semiconductor device, P type diffusion regions 7 and 17 used as back gate regions are formed while shifting a peak of an impurity concentration. In the back gate region, a concentration profile is formed gently in a region for forming an N type diffusion region 25. After implanting impurity ions for forming the N type diffusion region 25, the N type diffusion region 25 is diffused in aγ-shape under a gate electrode 22 by heat treatment. Electric field relaxation can be achieved in the drain region by this manufacturing method. COPYRIGHT: (C)2007,JPO&INPIT
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