Process for forming bipolar transistor compatible with CMOS utilizing tilted ion implanted base

Claim 1

A process for forming a bipolar transistor comprising the steps of: forming a buried highly doped collector region of the first conductivity type in a semiconductor material; forming a well of a first conductivity type over the buried highly doped collector region; forming a dielectric layer having a window over the collector region in the well; introducing dopant of a second conductivity type opposite the first conductivity type through the window to form an intrinsic base region; forming a polysilicon layer over the dielectric layer and within the window; introducing dopant of the first conductivity type into the polysilicon layer; etching the polysilicon layer to form a polysilicon emitter contact component structure extending at least over the window; introducing dopant of the first conductivity type into the semiconductor material directly underneath the polysilicon emitter contact component and above the intrinsic base to form a single crystal emitter component; and ion-implanting dopant of the second conductivity type at an angle of less than 90° to the semiconductor material to form a link base region, the link base region extending underneath the polysilicon emitter contact component and overlapping the intrinsic base region.