Semiconductor device having a high breakdown voltage.

摘要

This invention concerns a so-called double-moat uni- surface type semiconductor device in which two concentric moats (9,10) are provided in one main surface of the substrate and the edges of the two pn-junctions (JI,J2) for blocking main circuit voltages applied to the device are exposed in the surfaces of the moats. The moats are filled with surface passivating material (11,12). In order to increase the voltage withstood by the device, irrespective of whether negative or positive charges are induced atthe interface of the semiconductor substrate and the passivating material, semiconductor layers (6,7,8) having high impurity concentrations and serving as channel stoppers are formed in the semiconductor layers exposed at the one main surface of the substrate, contiguous to the moats and spaced from the pn-junctions. Each such high impurity concentration layer (6,7,8) has the same conductivity type as the semiconductor layer in which it is formed.