JPS6447070A - Manufacture of transistor with broad band gap emitter - Google Patents

Abstract

PURPOSE:To make an allowance for the positional deviation of an emitter in a base region be dispensed with, whereby the base region is made to be able to decrease in area by a method wherein a patterning is performed onto a laminated layer which consists of an n-type SiC layer and a mask layer formed on a substrate so as to mask an element forming region for the formatrion of an element isolating layer and then the peripheral section of the SiC layer is subjected to a selective etching to recede. CONSTITUTION:An epitaxial layer 3, a SiC layer 5 with a broad band gap, and a Si3N4 layer 6 which are to constitute a broad band gap emitter are successively formed on a substrate 1 where an n-type epitaxial layer 3 and a p-type diffusion layer 4 to constitute a base region are formed. The Si3N4 layer 6 and the SiC layer 5 are selectively removed and an element isolating layer 7 is formed on the peripheral section of an element forming region through the layers left unremoved as a mask, and then the peripheral section of the SiC layer 5 is subjected to selective etching to make it recede so as to form a broad band gap emitter 5a and the diffusion layer 4 is made to be exposed around the emitter 5a for the formation of a base contact region, thereafter a conductive layer 81 extending over the element isolating layer 7 is provided to form a base region lead-out wiring.