V-Mos field effect transistor

Claim 1

An insulated gate field effect transistor comprising a semiconductor body having a layer-shaped first region of a first conductivity type adjoining a surface, an underlying layer-shaped second region of the second opposite conductivity type, which form a p-n junction with the first region, and an island-shaped zone of the second conductivity type which adjoins the surface and which is surrounded by the first region, at least one groove of V-shaped cross-section in the surface, which extends through the island-shaped zone and the first region into the second region and the walls of which are coated with an electrically insulating layer, a conductive layer being provided on said insulating layer and forming a gate electrode of the field effect transistor, the island-shaped zone and the second region being provided with source and drain electrodes, characterized in that an electrically insulating filler material different from that of said electrically insulating layer is provided in the lower part of the groove between the gate electrode and the bottom of the groove.