Transistor with field electrodes and improved avalanche breakdown behavior

Abstract

A transistor cell includes, in a semiconductor body, a drift region of a first doping type, a source region of the first doping type, a body region of a second doping type, and a drain region of the first doping type. The body region is arranged between the source and drift regions. The drift region is arranged between the body and drain regions. A gate electrode is adjacent the body region and dielectrically insulated from the body region by a gate dielectric, and a field electrode is dielectrically insulated from the drift region by a field electrode dielectric. The drift region includes an avalanche region having a higher doping concentration than sections of the drift region adjacent the avalanche region and which is spaced apart from the field electrode dielectric in a direction perpendicular to the current flow direction. The field electrode is arranged in a needle-shaped trench.