PURPOSE: To prevent a latchup in a vertical bipolar MOSFET by forming the same conductivity type diffused layer as that of a channel diffused layer at the periphery of a channel diffused layer, and connecting it to a source electrode.
CONSTITUTION: The same conductivity type p-type diffused layer 11 as a p-type diffused layer (channel diffused layer, base) 5 is formed around the layer 5, and electrically connected to an emitter electrode 1. When thus constructed, when a positive gate voltage is applied to a gate electrode 3, the surface of the layer 5 is first inverted to n-type, and an electron current (d) flows from a source (emitter) side to a drain side. Thus, diffused holes from a p-type layer 9 branched to a, c, e, f. In this manner, a hole current to be implanted to the layer 5 which cause a latchup can be largely reduced.
YAMANAKA KAZUO
SUEYOSHI SATOSHI
