Patent ID: 6194280
Filing Date: 2001-02-27
Classification: H01L

Abstract:
A method for constructing a bipolar transistor in a bipolar process, comprising the step of:providing a semiconductor substrate having a collector region;forming a base polysilicon electrode layer on the collector region;forming an inter-polysilicon dielectric layer, having a first dopant, on the base polysilicon layer;forming a capping layer on the inter-polysilicon dielectric layer;forming a window through the capping layer, inter-polysilicon dielectric layer, and base electrode layer to open to a top surface of the substrate;forming an intrinsic base region in the collector region;forming an emitter electrode layer, having a second dopant, on the capping layer and extending into the window to contact the intrinsic base region;diffusing the first dopant from the inter-polysilicon dielectric layer into the collector region to form an extrinsic base region and a base link-up region;diffusing the second dopant from the emitter electrode layer into the intrinsic base region to form an emitter region therein;covering the emitter electrode with patterned photoresist to selectively cover the emitter electrode over the window;etching the emitter electrode layer, the capping layer, and the inter-polysilicon dielectric layer to remove the layers from the base polysilicon electrode where not covered with photoresist.