Bonded IC substrate with a high breakdown voltage and large current capabilities

摘要

A semiconductor device includes a groove formed in a surface of a first semiconductor substrate of one conductivity type in order to partition and isolate first and second device regions. A first insulating film on the first semiconductor substrate of the first device region also contacts the groove. A second insulating film covers an inner wall of the groove. The first insulating film is thicker than the second film in order to increase the breakdown voltage and facilitate carrying a higher current. This thickness relationship also aids manufacturing.