There is disclosed an IGBT which includes an n.sup.+ layer (2A) , an n.sup.- layer (2B) , a p well region (3), an n.sup.+ diffusion region (4), a gate oxide film (5), a gate electrode (6) and an emitter electrode (8) around the upper major surface of a p.sup.+ substrate (1), similarly to conventional...http://www.google.fr/patents/US5289019?utm_source=gb-gplus-shareBrevet US5289019 - Insulated gate bipolar transistor
