P A P E R    T I T L E
Effects of Ballast Resistors on Power and ESD Performance in AlGaAs/GaAs Heterojunction Bipolar Transistors

A U T H O R  /  C R E D I T S
Charles Y. Chu, Jerry J. Sheu, and G.P. Li
Department of Electrical and Computer Engineering
University of California, Irvine, 92697
E-mail: cchu@newport.uci.edu, Tel: (949) 824-2047, Fax: (949) 824-3732
W. J. Ho, H. Y. Hsu, T-M Kao, C. Hua, and Ding Day
Network Device Inc., 1230 Bordeaux Dr., Sunnyvale, CA 94089-1202

A B S T R A C T
The effects of ballast resistors on design tradeoff between forward bias ESD robustness and peak power handling capability were studied for the first time in power AlGaAs/GaAs heterojunction bipolar transistors. It is found that though a ballast resistor prevents transistors from the current gain collapse to achieve a better thermal stability at higher power density, it can also significantly reduce the forward biased ESD performance of the ballasted junction. A design criterion for optimizing ESD survivability and output power is explored.