| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a MOS device at a low cost, which has a high breakdown voltage MOS transistor and a low breakdown voltage MOS transistor. SOLUTION: An N<-> type semiconductor region 14 whose impurity concentration is low, and a P<-> type semiconductor region 13 whose impurity concentration is low, are formed simultaneously to a high breakdown voltage NMOS transistor and a low breakdown voltage NMOS transistor, and N<-> semiconductor regions 15 whose impurity concentration is low are formed simultaneously to the high breakdown voltage NMOS transistor and a low breakdown voltage PMOS transistor, thereby reducing ion implantation process and a photomask necessary for it.
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