| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device having a p-type MOS transistor which is a middle power type and has low on-resistance and an offset drain by using an ordinary P-type semiconductor substrate.SOLUTION: A semiconductor device comprises: a P-type semiconductor substrate (21) which is a semiconductor substrate of a first conductivity type; a deep first well (25) of a second conductivity type, which is formed in the semiconductor substrate (21) of the first conductivity type; a second well (31b) of the first conductivity type, which is formed in the deep first well (25); an offset-drain P-type MOS transistor formed in the second well (31b); and a third well (33) of the second conductivity type, which is formed on a source part of the offset-drain P-type MOS transistor in the second well (31b). In this way, a P-type LDMOS structure can be formed by using an ordinary P-type semiconductor substrate and a semiconductor device having a p-type MOS transistor which is a middle power type and has low on-resistance and an offset drain can be provided. |
