Blocking of boron diffusion through the emitter-emitter poly interface in PNP HBTs through use of a SiC layer at the top of the emitter epi layer
US6552375B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Mar 4, 2002 |
| Grant date | Apr 22, 2003 |
| Priority date | — |
| Expiry date | Mar 4, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D62/8325
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The present invention relates to a heterojunction bipolar transistor, and comprises a collector region, and a graded profile SiGe base layer overlying the collector region. The transistor further comprises a diffusion blocking layer overlying the graded profile SiGe base layer, and an emitter layer overlying the diffusion blocking layer. The diffusion blocking layer is operable to retard a diffusion of dopants therethrough from the emitter layer to the graded profile SiGe base layer, thereby allowing for a reduction in the thickness of the layer comprising a graded profile SiGe layer and a buffer layer. The thickness reduction allows increased Ge concentration in the base layer and the emitter/base doping profile is improved, each leading to improved transistor performance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.