| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a semiconductor device of good performance by precisely controlling the impurity concentration of a semiconductor layer formed in another semiconductor layer of different impurity concentration. SOLUTION: A trench is formed at an n-type epi-layer of a drift region (process S10), and then a p-type epi-film is deposited (process S12). The p-type epi-film is polished (process S14), so that the p-type epi-layer of a channel formation region is formed at the n-type epi-layer. Thus, the p-type epi-film is embedded in the trench by a CVD method, which is polished to form such p-type epi-layer whose conductivity is different at the n-type epi-layer, allowing precise control of impurity concentration as with ion implantation method. As a result, the electric conductivity of a p-type epi-layer 16 is precisely controlled for manufacturing a high-performance DMOSFET.
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