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US 8,525,233 B1Granted
SiGe heterojunction bipolar transistor with a shallow out-diffused P+ emitter region
AssigneeTexas Instruments Incorporated
InventorsJeffrey A. Babcock, Alexei Sadovnikov
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Abstract
A pnp SiGe heterojunction bipolar transistor (HBT) reduces the rate that p-type dopant atoms in the p+ emitter of the transistor out diffuse into a lowly-doped region of the base of the transistor by epitaxially growing the emitter to include a single-crystal germanium region and an overlying single-crystal silicon region.
Claims12
A bipolar structure comprising:
- a substrate structure having a first conductivity type;
- a first epitaxial structure that touches the substrate structure, the first epitaxial structure including single-crystal silicon;
- a second epitaxial structure that touches the first epitaxial structure, the second epitaxial structure including a first single-crystal germanium region, the first single-crystal germanium region having a second conductivity type;
- a non-conductive structure that touches the second epitaxial structure, the non-conductive structure having an emitter opening that exposes the second epitaxial structure;
- and
- a third epitaxial structure that touches the non-conductive structure and extends through the emitter opening to touch the second epitaxial structure, the third epitaxial structure including a second single-crystal germanium region, the second single-crystal germanium region having the first conductivity type.
3 more elements
Dependencies are inferred from the claim text.