JPS54141596A - Semiconductor device - Google Patents

Abstract

PURPOSE: To improve dielectric strength by providing an operation region of opposite conductivity type within a semiconductor substrate of one conductivity type, encircling the outer side thereof with a first guard ring of the same conductivity type and a low impurity concentration and further encircling this with a second guard ring of the same conductivity type as that of the substrate and a low concentration.

CONSTITUTION: A π type first epitaxial layer 2 of an extremely low impurity concentration and a P type second epitaxial layer 3 of an impurity concentration slightly higher than this are epitaxially grown in lamination on a P⁺ type Si substrate 1. Next, an N⁺ type operating region 4 is diffusion formed in the layer 3 to grow a PN junction between these. Thereafter an N^- type first guard ring 5 is provided in contact with the surface region of the region 4 within the layer 3 and further a P^- type second guard ring 6 of a impurity concentration lower than that of the layer 3 is diffusion formed in contact with the outer side thereof. Next, a shallow P⁺ type channel stopper region 7 entering this ring 6 is provided on the outer side of this ring and the portions other than the region 4 are covered with a protecting film 8 such as SiO₂.

COPYRIGHT: (C)1979,JPO&Japio