Patent ID: 6472262
Filing Date: 2002-10-29
Classification: H01L

Abstract:
A method for fabricating a self-aligned double-polysilicon type bipolar transistor with a heterojunction base comprising the steps of:forming a semiconductor substrate with an active region; forming an isolating region that surrounds the active region of the semiconductor substrate; and forming a semiconducting heterojunction region on top of the active region and the isolating region by non-selective epitaxy; forming a stack on top of the active region comprising the sub-steps of: disposing an etch stop layer on top of the active region; disposing a polysilicon layer having the same type of conductivity as the semiconducting heterojunction region, wherein the polysilicon layer is overdoped with respect to the semiconducting heterojunction region; disposing at least one upper insulating layer; defining an emitter window with an outer periphery above the active region by etching the stack so as to stop at the etch stop layer; replacing the etch stop layer by an electrically conducting replacement material at the outer periphery of the emitter window; and forming an emitter region resting partially on the at least one upper insulating layer.