JPS6448458A - Semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the loss of an element isolation function of an insulator buried layer by forming a reverse conductivity type semiconductor region along the inwall of the insulator buried layer isolating an element in a border-line region between a collector region and a base region. CONSTITUTION:A reverse conductivity type semiconductor layer 3 shaped onto one conductivity type semiconductor substrate 1 as a collector is used as a base, an emitter 5 composed of one conductivity type semiconductor layer is formed onto the base 3, and reverse conductivity type semiconductor regions 2 are shaped in regions adjacent through an insulator element isolation region on the same substrate 1. The reverse conductivity type semiconductor regions 2 are formed along the inwalls of insulator buried layers 4 isolating the element in a border-line region between the collector region 1 and the base region 3. Accordingly, a parasitic transistor unavoidably generated in a semiconductor device having the structure is difficult to be operated, thus preventing the loss of a function of element isolation consisting of the insulator buried layers 4.