| 主权项 |
1. A semiconductor device comprising:
a first semiconductor layer of a first conductivity type; a first electrode electrically connected to the first semiconductor layer; a second semiconductor layer of a second conductivity type provided on the first semiconductor layer; a third semiconductor layer of the first conductivity type selectively provided on the second semiconductor layer; a second electrode electrically connected to the second semiconductor layer and the third semiconductor layer; a third electrode provided from an upper surface side of the third semiconductor layer through the third semiconductor layer and the second semiconductor layer to the first semiconductor layer via a first insulating film; a floating electrode provided from an upper surface side of the third semiconductor layer through the third semiconductor layer and the second semiconductor layer to the first semiconductor layer via a first insulating film; and a second insulating film provided between the second electrode and the third electrode, the second electrode and the floating electrode, a voltage BV0 between the first electrode and the second electrode is lower than an avalanche breakdown voltage BV1 of the semiconductor device without the floating electrode and the voltage BV0 is given by the following formulas:
BV0=((Cfd+Cfs)/CfdXVth, where Cfd is a capacitance between the floating electrode and the first electrode, Cfs is a capacitance between the floating electrode and the second electrode and Vth is threshold voltage of the floating electrode. |
