| 摘要 |
PROBLEM TO BE SOLVED: To provide a power MOS transistor incorporating a bidirectional polysilicon Zener diode between drain and gate in which placement of bidirectional polysilicon Zener diodes is improved. SOLUTION: A power MOS transistor is placed in the central part 11 of a semiconductor substrate, a gate interconnection layer 12 is formed on the semiconductor substrate while surrounding the central part 11 and a heavily doped semiconductor region 13 is formed on the outer circumferential part of the semiconductor substrate and connected with the drain of the power MOS transistor. Bidirectional polysilicon Zener diodes 14 comprising a large number of pairs of Zener diodes connected in reverse series between the drain and gate of the power MOS transistor are arranged along the diametral direction of the semiconductor substrate.
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