Effect of Ge content and profile in the SiGe base on the performance of a SiGe/Si heterojunction bipolar transistor

✍ Scribed by Mukul K. Das; N. R. Das; P. K. Basu

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 217 KB
• Volume: 47
• Category: Article
• ISSN: 0895-2477
• DOI: 10.1002/mop.21138

✦ Synopsis

In this paper, the effects of Ge content and profile shape on the performance of a SiGe-based heterojunction bipolar transistor (HBT) are investigated. The common-emitter current gain, the early voltage, and the transit time of SiGe HBTs are calculated and computed for different Ge profiles as well as the total Ge content in the base, considering uniform base-doping. Then the effects of the above on the cutoff frequency f and the maximum oscillation frequency f max of the HBT are shown. It is seen that both the forward current gain and the transit time decrease with the change in profile from box to triangle, but the early voltage increases with a similar change. The increase of Ge content for the same profile results in a decrease of transit time. From the analysis, a large increase in f and f max can be predicted with a suitable choice of Ge profile and the total Ge content in the base.