Patent ID: 6319786
Filing Date: 2001-11-20
Classification: H01L

Abstract:
A method for manufacturing a bipolar transistor, including the steps of:defining an active area in a surface of a silicon layer of a first conductivity type;depositing a polysilicon layer doped of a second conductivity type and an insulating layer;defining in said layers a base-emitter opening;doping according to the second conductivity type and annealing to form a heavily-doped region partially extending under a periphery of the polysilicon layer;forming a spacer made of an insulating material inside the opening;isotropically etching the silicon across a depth greater than that of the heavily-doped region to form a recess;conformally forming, by selective epitaxy, a silicon layer of the second conductivity type to form the transistor base layer; anddepositing polysilicon heavily-doped of the first conductivity type to form the transistor emitter.