Title :
Base transit time of a heterojunction bipolar transistor (HBT) with Gaussian doped base under high-level of injection
Author :
Islam, Shekh Md Mahmudul ; Chowdhury, M.I.B. ; Arafat, Yeasir ; Khan, Md Ziaur Rahman
Author_Institution :
Dept. of Electr. & Electron. Eng., United Int. Univ., Dhaka, Bangladesh
Abstract :
Base transit time for an npn SiGe HBT has been analysed assuming Gaussian doped base considering doping dependent mobility. Band-gap narrowing (BGN) effects due to heavy doping, due to presence of Germanium and due to change in the density of states (DOS) have also been considered. The presence of Ge has been incorporated by using a different saturation velocity for the SiGe alloy. A generalized profile for Ge mole fraction distribution is used, where Ge profile variation has been illustrated by varying a single parameter for box, trapezoidal and triangular forms. Base transit time of SiGe HBT has been calculated for these three Ge profiles under high level of injection.
Keywords :
Ge-Si alloys; carrier mobility; heterojunction bipolar transistors; semiconductor doping; BGN effects; Gaussian doped base; HBT; SiGe; band gap narrowing effects; base transit time; density of states; doping dependent mobility; heterojunction bipolar transistor; mole fraction distribution; profile variation; saturation velocity; Band gap narrowing; Base transit time; Density of states; Gaussian doping; HBT;
Conference_Titel :
Devices, Circuits and Systems (ICDCS), 2012 International Conference on
Conference_Location :
Coimbatore
Print_ISBN :
978-1-4577-1545-7
DOI :
10.1109/ICDCSyst.2012.6188685
