Surge protection device

Abstract

In a breakover type surge protection device utilizing punch-through that comprises a second semiconductor region forming a first pn junction with a first semiconductor region, a third semiconductor region forming a second pn junction with the second semiconductor region and a fourth semiconductor region forming a third pn junction with the first semiconductor region at a place apart from the second semiconductor region, the second semiconductor region is constituted of a punch-through suppression region portion disposed to cover the corners of the third semiconductor region and a punch-through generation region portion disposed at a place where its thickness can be made uniform. Fabricating surge protection devices according to this configuration reduces variation among their breakover currents and hold currents and increases their surge absorption capacity.