Integrable mos and igbt devices having trench gate structure

Abstract

A power semiconductor device which is integrable in an integrated circuit includes a semiconductor body having first and second major opposing surfaces with a first doped region of a first conductivity type therebetween, second and third doped regions of a second conductivity type formed in the first doped region, the second and third doped regions being spaced apart and abutting the first surface, and fourth and fifth doped regions of the first conductivity type respectively formed in the second and third doped regions and abutting the first surface. Sixth and seventh doped regions extend from the first surface into the first region, the sixth region being adjacent to the second and fourth regions and spaced therefrom by an electrically insulative layer, the seventh region being adjacent to the third and fifth regions and spaced therefrom by an insulative layer. The first doped region extends toward the first surface between the sixth and seventh regions and separated therefrom by an electrically insulative layer of variable thickness suitable for voltage blocking. An eighth doped region in the first doped region between the sixth and seventh regions abuts the first surface and forms the drain of a MOSFET or the anode of an IGBT. In fabricating the device, reactive ion etching is used to from a trench in which the sixth and seventh regions are formed. The trench is filled by epitaxially grown semiconductor material in which the eighth doped region is formed. The fourth and fifth doped regions form the source of a MOSFET or a cathode of an IGBT. All ohmic contacts to the device can be made on the first surface.