High-Power High-Temperature Heterobipolar TransistorWith Gallium Nitride
Emitter
J. I. Pankove, M. Leksono, S. S. Chang, C. Walker
Astralux Inc.
B. Van Zeghbroeck
University of Colorado
This article was received on Thursday, August 15, 1996 and
accepted on Thursday, November 28, 1996. Abstract
A new heterobipolar transistor was made with the wide bandgap
semicon-ductors gallium nitride (GaN) and silicon carbide (SiC). The
heterojunction allows high injection efficiency, even at elevated
temperatures. A record current gain of ten million was obtained at room
temperature, decreasing to 100 at 535°C. An Arrhenius plot of current gain vs
1/T yields an activation energy of 0.43 eV that corresponds to the valence band
barrier blocking the escape of holes from the base to the emitter. This
activation energy is approximately equal to the difference of energy gaps
between emitter and base. This Transistor can operate at high power without
cooling. A power density of 30 KW/cm