Patent ID: 7202531

Claim:
A semiconductor device comprising, above a semiconductor region of a first conductivity type, an output pad, a driver element connected to the output pad, a control circuit, and a surge absorption unit for preventing misoperation of the control circuit and protecting the driver element against a surge, wherein the surge absorption unit comprises: a semiconductor island region of a second conductivity type formed in or above the semiconductor region of the first conductivity type; a buried layer of the second conductivity type formed between the bottom of the semiconductor island region of the second conductivity type and the semiconductor region of the first conductivity type; a dopant layer of the first conductivity type formed in an upper portion of the semiconductor island region of the second conductivity type and electrically connected to have the same potential as the semiconductor region of the first conductivity type; a dopant layer of the second conductivity type formed in an upper portion of the dopant layer of the first conductivity type and electrically connected to the output pad; and a ring layer of the second conductivity type formed in the semiconductor island region of the second conductivity type to surround the dopant layer of the first conductivity type and to reach the buried layer of the second conductivity type, the ring layer of the second conductivity type is electrically connected to a terminal with a fixed potential and contains a dopant of the second conductivity type having a higher concentration than the semiconductor island region of the second conductivity type, the control circuit is arranged around the surge absorbing unit, and the dopant layer of the second conductivity type is electrically connected to an inductive load from outside through the output pad.