Influence of low doped emitter and collector regions on high-frequency performance of SiGe-base HBTs
| Autor: | F Herzel, B Heinemann, U Zillmann |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Materials science
business.industry Heterojunction bipolar transistor Gaussian Doping Electrical engineering chemistry.chemical_element Transit time Condensed Matter Physics Capacitance Electronic Optical and Magnetic Materials symbols.namesake chemistry Materials Chemistry symbols Optoelectronics Electrical and Electronic Engineering business Base (exponentiation) Boron Common emitter |
| Zdroj: | Solid-State Electronics. 38:1183-1189 |
| ISSN: | 0038-1101 |
| Popis: | The high-frequency behavior of a Si/Si1−xGex/Si heterojunction bipolar transistor is investigated by means of a two-dimensional device simulation program. A simplified method based on the quasi-static approximation and the well-known formula fmax=√ft8πRBCc is compared with the more accurate a.c. small-signal analysis in order to estimate the limits of the first approach. For a given Gaussian boron distribution in the base an optimized Ge profile is derived exploiting its influence on the spatial distribution of the transit time. Our main attention is directed to the dependence of fT and fmax on the vertical profile in the low doped regions of emitter and collector. The study of the tradeoff between the capacitance of the BC junction and the transit frequency shows that a small capacitance CC at the expense of fT is favorable for obtaining high fmax values. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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