Method in the manufacturing of a semiconductor device

Abstract

A method of manufacturing a bipolar transistor having a self-registered base-emitter structure is provided. The method involves the steps of: depositing a layer of amorphous silicon on a substrate of crystalline silicon having an upper region of a first conductor type; doping the amorphous silicon layer with a dopant to form a second conductor type; depositing at least one dielectric layer on the amorphous silicon layer in a manner such as to prevent crystallization of the amorphous silicon layer; patterning the resultant structure and thereafter etching away the dielectric layer and the amorphous silicon layer within a predetermined region such as to define an emitter opening; growing a thermal oxide on the resultant structure, wherein the amorphous silicon layer is converted to a polycrystalline silicon layer; forming an intrinsic base of the same conductor type as the polycrystalline layer by doping through the thermal oxide; depositing a layer of electrically insulating material on the resultant structure and thereafter etching the structure anisotropically until a thin oxide layer remains on the substrate in the emitter opening and in such a manner that a spacer of the electrically insulating material remains along the side walls of the emitter opening; removing the thin oxide layer; forming an emitter contact in the emitter opening and doping the emitter contact to the first conductor type; and heat-treating the structure to form an emitter-base junction in the substrate by out diffusion of the dopants from the emitter contact.