Self-aligned SiGe HBT BiCMOS on SOI substrate and method of fabricating the same
AssigneeSharp Laboratories of America, Inc.
InventorSheng Teng Hsu
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Abstract
A SiGe HBT BiCMOS on a SOI substrate includes a self-aligned base/emitter junction to optimize the speed of the HBT device. The disclosed SiGe BiCMOS/SOI device has a higher performance than a SiGe BiCMOS device on a bulk substrate. The disclosed device and method of fabricating the same also retains the high performance of a SiGe HBT and the low power, high-speed properties of a SOI CMOS. In addition, the disclosed method of fabricating a self-aligned base/emitter junction provides a HBT transistor having an improved frequency response.
Claims7
A method of fabricating a self-aligned SiGe HBT BiCMOS on a SOI substrate, comprising the steps of:
- providing a silicon on insulator substrate having a buried oxide layer;
- etching a collector region in said buried oxide layer;
- depositing an epitaxial layer in said collector region;
- depositing a first polysilicon layer on said epitaxial layer in said collector region;
- etching a trench in said first polysilicon layer in said collector region;
- etching a void below said trench wherein said void is operatively connected to said trench and said epitaxial layer;
- depositing a SiGe base layer in said void such that said SiGe base layer is operatively connected to said trench and is in contact with said epitaxial layer;
- depositing a second polysilicon layer in said trench such that said second polysilicon layer is in contact with said SiGe base layer;
- connecting said second polysilicon layer to an emitter contact;
- and
- connecting said SiGe base layer to a base contact, wherein said emitter contact and said second polysilicon layer are self-aligned with said SiGe base layer.
Dependencies are inferred from the claim text.