JPS6472560A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form small intrinsic base and emitter regions to miniaturize the title device in a self-alignment manner by forming an outer base whose upper and side faces are covered with insulating films and which protrudes on a substrate, and then diffusing an impurity in the substrate surrounded by the outer base to form the intrinsic base and emitter regions. CONSTITUTION:The upper face of one conductivity type silicon substrate 1 is covered with an antioxidation film 7a, the part of the film 7a is removed to form a window 7c for exposing the substrate on the periphery of a region to be an emitter region, the window 7c is filled with the opposite conductivity type silicon 3b, and with the film 7a as a mask the surface of the filled silicon 3b is thermally oxidized at 8a, and the remaining film 7a is removed. Then, an oxide film 8b is formed on the side face of the filled region 3b remaining on the substrate 1, the upper and side faces ar covered with the insulating films 8a, 8b to form an outer base 3b made of the silicon region protruding on the substrate 1. Thereafter, an impurity is diffused in the substrate 1 surrounded by the base 3b to form intrinsic base and emitter regions 3a and 4, thereby forming a bipolar transistor.