Patent ID: 6180478
Filing Date: 2001-01-30
Classification: H01L

Abstract:
A method of fabricating a bipolar junction transistor, (BJT), on a semiconductor substrate, comprising the steps of;forming a subcollector region, of a first conductivity type, in a first region of said semiconductor substrate, with said semiconductor substrate, comprised of a second conductivity type;depositing a first epitaxial silicon layer, comprised with a dopant of said first conductivity type;forming diffusion isolation regions, of said second conductivity type, in a first region of said first epitaxial silicon layer, and in a second region of said semiconductor substrate;forming insulator isolation regions, in regions of said first epitaxial silicon layer, directly overlying said diffusion isolation regions;forming a collector reach through region, of said first conductivity type, in a third region of said first epitaxial silicon layer, leaving a fourth region of said first epitaxial layer, as an active device region;forming a silicon seed layer on said insulator isolation regions, and on portions of said active device region, adjacent to said insulator isolation regions;forming a second epitaxial silicon layer, on said active device region, and on regions covered by said silicon seed layer;forming an extrinsic base region, of said second conductivity type, in first regions of said second epitaxial silicon layer;patterning of said second epitaxial silicon layer;forming an intrinsic base region, of said second conductivity type, in a second region of said second epitaxial silicon layer;forming an emitter opening, in a silicon oxide layer, exposing a portion of the top surface of said intrinsic base region;forming a polysilicon emitter structure, comprised with a dopant of said first conductivity type, overlying and contacting the portion of said intrinsic base region, exposed in said emitter opening;performing an annealing procedure, to form an emitter region, of said first conductivity type, in a top portion of said intrinsic base region; andforming metal contact structures, to said polysilicon emitter structure, to said extrinsic base region, and to said collector reach through region.