Patent ID: 9673320
Date: 2017-06-06
CPC Classifications: H01L

Claim:
1. A transistor device comprising at least one transistor cell, wherein the at least one transistor cell comprises: in a semiconductor body, a drift region of a first doping type, a source region of a first doping type, a body region of a second doping type, and a drain region of the first doping type, wherein the body region is arranged between the source region and the drift region, wherein the drift region is arranged between the body region and the drain region, and wherein the source region and the drain region are spaced apart in a first lateral direction of the semiconductor body; a gate electrode adjacent the body region and dielectrically insulated from the body region by a gate dielectric; a field electrode arranged in the drift region and dielectrically insulated from the drift region by a field electrode dielectric; a source electrode electrically connected to the source region and the body region and arranged in a trench extending from a first surface of the semiconductor body into the semiconductor body; a drain electrode electrically connected to the drain region and arranged in a trench extending from a first surface of the semiconductor body into the semiconductor body; and an avalanche bypass structure coupled between the source electrode and the drain electrode and comprising a first semiconductor layer of the first doping type, a second semiconductor layer of the first doping type, and a pn-junction arranged between the first semiconductor layer and the source electrode, wherein the second semiconductor layer has a higher doping concentration than the first semiconductor layer, wherein the first semiconductor layer is arranged between the second semiconductor layer and the drift region, and wherein the drain electrode is electrically connected to the second semiconductor layer.