METHOD OF MAKING BIPOLAR PLANAR TRANSISTORS

摘要

A method of manufacturing bipolar transistors is described. The emitter areas are protected by means of an oxidation masking layer and subsequently after applying a photo-resist layer which defines the base areas two implantation processes of ions of the base zone conductivity type are performed. The one is performed with low doping dose and high acceleration voltage sufficient to render the masking layer penetrable and the other with high doping dose and low acceleration voltage as to render the masking layer impenetrable.