Model of transit time for SiGe HBT collector junction depletion-layer
Hu Hui-Yong (胡辉勇), Zhang He-Ming (张鹤鸣), Dai Xian-Ying (戴显英), Jia Xin-Zhang (贾新章), Cui Xiao-Ying (崔晓英), Wang Wei (王伟), Ou Jian-Feng (区健锋), Wang Xi-Yuan (王喜媛)
Institute of Microelectronics, Xidian University, Xi'an 710071,China
Abstract The transit time through collector junction depletion-layer is an important parameter that influences AC gain and frequency performance. In SiGe heterojunction bipolar transistor (HBT) collector junction, the depletion-layer width is given in three cases. The models of collector depletion-layer transit time, considering the collector current densities and base extension effect, are established and simulated using MATLAB. The influence of the different collector junction bias voltage, collector concentration of As or P dopant and collector width on collector junction transit time is quantitatively studied. When the collector junction bias voltage, collector doping concentration and collector width are large, the transit time is quite long. And, from the results of simulations, the influence of the collector depletion-layer transit time on frequency performance is considerable in SiGe HBT with a thin base, so it could not be ignored.
Received: 06 December 2004
Revised: 23 March 2005
Accepted manuscript online:
(Semiconductor-device characterization, design, and modeling)
Fund: Project supported by the National Defence Pre-research Foundation of China (Grant No 41308060108).
Cite this article:
Hu Hui-Yong (胡辉勇), Zhang He-Ming (张鹤鸣), Dai Xian-Ying (戴显英), Jia Xin-Zhang (贾新章), Cui Xiao-Ying (崔晓英), Wang Wei (王伟), Ou Jian-Feng (区健锋), Wang Xi-Yuan (王喜媛) Model of transit time for SiGe HBT collector junction depletion-layer 2005 Chinese Physics 14 1439
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