Method to fabricate SiGe HBTs with controlled current gain and improved breakdown voltage characteristics
AssigneeInternational Business Machines Corporation
InventorsDavid R. Greenberg, Basanth Jagannathan, Shwu-Jen Jeng, Joseph T. Kocis, Samuel C. Ramac, David M. Rockwell
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Abstract
A method of fabricating a SiGe heterojunction bipolar transistor (HBT) is provided which results in a SiGe HBT that has a controllable current gain and improved breakdown voltage. The SiGe HBT having these characteristics is fabricated by forming an in-situ P-doped emitter layer atop a patterned SiGe base structure. The in-situ P-doped emitter layer is a bilayer of in-situ P-doped a:Si and in-situ P-doped polysilicon. The SiGe HBT structure including the above mentioned bilayer emitter is also described herein.
Claims9
A SiGe heterojunction bipolar transistor structure comprising:
- a patterned SiGe base structure which includes at least a SiGe layer present atop a substrate and a patterned insulator present on a portion of said SiGe layer having an opening that exposes a portion of said SiGe layer;
- and
- an emitter layer formed atop said SiGe base structure including in said opening, said emitter layer is a bilayer of in-situ P-doped a:Si and in-situ P-doped polysilicon.
Dependencies are inferred from the claim text.