Power transistor for monolithic integrated circuit - has low collector resistance achieved by using two extra domains of opposite conduction type

摘要

The power transistor may be incorporated in a semiconductor integrated circuit. It has a substrate with an epitaxial layer on one face. A collector zone is formed in the epitaxial layer and a base zone is formed in the collector zone. An emitter zone is formed in the base zone. The substrate is divided into at least two domains of opposite conduction type. The first domain has the same conduction type as the epitaxial layer and extends through the full depth of the substrate. This first domain forms a conduction zone and an output zone adjacent to the collector zone. The first domain or output zone is extended laterally by a semiconductor zone of the same conduction type stretching at least over the entire surface of the second domain situated opposite the face of the substrate opposite to that supporting the epitaxial layer.