Field effect transistor and application device thereof

Abstract

The present invention provides a MOSFET having a low on-state resistance and a high withstand voltage as well as a small output capacitance (C(gd), etc.). The MOSFET has a p-type base layer 4 and a n-type source layer 5 selectively formed on the surface of the p-type base layer 4. A n-type drain layer 7 is formed in a position apart from the p-type base layer 4. On the surface of the region between the p-type base layer 4 and the n-type drain layer 7, a n-type drift semiconductor layer 12 and a p-type drift semiconductor layer 13 are alternately arranged from the p-type base layer 4 to the n-type drain layer 7. Further, in the region between the n-type source layer 5 and the n-type drain layer 7, a gate electrode 15 is formed via a gate insulating film 14. With the structure, the neighboring region of the gate electrode is depleted by a built in potential between the n-type drift semiconductor layer 12 and the p-type drift semiconductor layer 13 or by the potential of the gate electrode, when the gate electrode, source electrode, and drain electrode are at 0 potential.

Dependencies are inferred from the claim text.