A parasitic transistor of an insulated gate semiconductor device does not easily turn on, so that an SOA of the insulated gate semiconductor device is improved. P.sup.+ semiconductor layers (45) having a higher impurity concentration than that N.sup.+ emitter layers (44) are disposed so that the...http://www.google.de/patents/US5801408?utm_source=gb-gplus-sharePatent US5801408 - Insulated gate semiconductor device and method of manufacturing the same
