Complementary transistor structure having two epitaxial layers and method of manufacturing same

Claim 1

A semiconductor device having a substantially planar semiconductor body including at least first and second complementary transistors each having emitter, base and collector zones and comprising a substrate of a first conductivity type which is covered with a first epitaxial layer of a second conductivity type opposite to that of the first, at least a part of said substrate comprising the collector zone of the first transistor, the base zone of said first transistor and the collector zone of the second complementary transistor comprising adjacent, electrically connected parts of said first epitaxial layer, and a second epitaxial layer of said first conductivity type provided on the first epitaxial layer and the emitter zone of the first transistor and the base zone of the second transistor comprise portions of said second epitaxial layer, said portions of the second epitaxial layer being separated from each other by at least one groove having a sufficient depth to extend through said second epitaxial layer entirely and to extend only partially into said first epitaxial layer, and an emitter zone of said second transistor formed in that part of said second epitaxial layer constituting the base zone of said second transistor, and means for providing circuit connections to zones of the first and second transistors.