A comprehensive study of lateral and vertical current transport in Si/Si/sub 1-x/Ge/sub xSi HBT's

We studied the effects of heavy doping and Ge concentration in the base on the dc performance of Si/Si/sub 1-x/Ge/sub xSi npn HBT's. The lateral drift mobility of holes in heavily doped epitaxial SiGe bases is found to be lower than bulk Si values and independent of Ge content, and the Hall sca...

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Bibliographic Details
Published inProceedings of IEEE International Electron Devices Meeting pp. 87 - 90
Main Authors Matutinovic-Krstelj, Z., Venkataraman, V., Prinz, E.J., Sturm, J.C., Magee, C.W.
Format Conference Proceeding
LanguageEnglish
Published IEEE 1993
Subjects
Charge carrier processes
Doping profiles
Electrons
Germanium silicon alloys
Hall effect
Heterojunction bipolar transistors
Photonic band gap
Scattering
Semiconductor process modeling
Silicon germanium
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Summary:We studied the effects of heavy doping and Ge concentration in the base on the dc performance of Si/Si/sub 1-x/Ge/sub xSi npn HBT's. The lateral drift mobility of holes in heavily doped epitaxial SiGe bases is found to be lower than bulk Si values and independent of Ge content, and the Hall scattering factor is less than unity and decreases with increasing Ge concentration. For the vertical electron transport we have observed bandgap narrowing due to heavy base doping which is, to first order, independent of Ge concentration. Finally, a model for the collector current enhancement with respect to Si devices, including the effects of reduced density of states in the strained Si/sub 1-x/Ge/sub x/ base and the effective bandgap due to Ge and heavy doping, is presented.< >
ISBN:9780780314504
0780314506
ISSN:0163-1918
2156-017X
DOI:10.1109/IEDM.1993.347392