Title :
Current crowding effects in SOI-SiGe HBTs with low doped emitters
Author :
Hall, S. ; Buiu, O. ; Lamb, A.C. ; Mubarek, H. A W EI ; Ashburn, P.
Author_Institution :
Dept. of Electr. Eng. & Electron., Liverpool Univ., UK
Abstract :
Anomalous limitation of collector and base current in SOI SiGe HBTs at moderate bias levels is shown to be the result of current crowding in the low doped emitter rather than in the base as is the case for homojunction transistors. Experimental results from devices with decreasing emitter window dimension, re-enforced by 2D simulation, show clearly a trend for crowding at the centre as the emitter resistance increases. The results have significance for achieving full optimisation of HBTs and in particular for medium power devices.
Keywords :
Ge-Si alloys; heterojunction bipolar transistors; semiconductor materials; silicon-on-insulator; SOI HBT; SiGe; base current limitation; bias level; collector current limitation; current crowding effects; emitter resistance; emitter window dimension; low doped emitter; low doped emitter HBT; optimisation; Capacitance; Epitaxial growth; Fabrication; Germanium silicon alloys; Heterojunction bipolar transistors; Leakage current; Proximity effect; Silicon germanium; Silicon on insulator technology; Windows;
Conference_Titel :
European Solid-State Device Research, 2003. ESSDERC '03. 33rd Conference on
Conference_Location :
Estoril, Portugal
Print_ISBN :
0-7803-7999-3
DOI :
10.1109/ESSDERC.2003.1256874
