High Frequency Property Optimization of Heterojunction Bipolar Transistors Using Geometric Programming

• Published in: AIP conference proceedings Vol. 963; pp. 997 - 1000
• Main Authors: Li, Yiming, Chen, Ying-Chieh
• Format: Journal Article
• Language: English
• Published: 01.01.2007
• ISSN: 0094-243X
• DOI: 10.1063/1.2836262

In this work, we theoretically optimize the high frequency property of silicon-germanium heterojunction bipolar transistors (HBTs) using a geometry programming (GP) technique. It is known that the base transit time of semiconductor devices potentially is a function of doping profile, device geometry and materials which significantly dominate the high frequency property of HBTs. To maximize the cut-off frequency of HBTs, the subject is formulated as a GP optimization problem by physically considering the base transit time as an object function. The GP model is solved numerically so that the cut-off frequency of HBT could be optimized for specified upper and lower bounds of the base doping concentration, and certain Ge composition. This work also shows that for 13% Ge profile, the cut-off frequency may reach a maximal value.