| 摘要 |
Accompanying the miniaturization of a gate electrode of a trench gate power MOSFET, the curvature of the bottom part of the trench increases, and thereby, electric fields concentrate on the part and deterioration of a gate oxide film (insulating film) occurs. The deterioration of the gate insulating film is more likely to occur when the gate side bias is negative in the case of an N-channel type power MOSFET and when the gate side bias is positive in the case of a P-channel type power MOSFET. The present invention is a semiconductor device including an insulating gate power transistor etc. in a chip, wherein a gate protection element includes a bidirectional Zener diode and the bidirectional Zener diode has a plurality of P-type impurity regions (or a P-type impurity region) having different concentrations so that the withstand voltage with its gate side negatively biased and the withstand voltage with the gate side positively biased are different from each other. |
