Summary: High current gain InGaN=GaN HBTs with
300
C operating temperature
D.M. Keogh, P.M. Asbeck, T. Chung, J. Limb, D. Yoo,
J.-H. Ryou, W. Lee, S.-C. Shen and R.D. Dupuis
High current gain InGaN base heterojunction bipolar transistors
(HBTs) with a graded emitter design are presented. The devices
show incremental current gain values above 30, and low offset and
knee voltages of approximately 2­3 and 5­6 V, respectively. Device
operation was demonstrated at temperatures as high as 300
C.
Introduction: InGaN=GaN heterojunction bipolar transistors (HBTs)
have met with considerable success recently; devices have been
reported with high current gain [1­3] and high voltage operation
[4, 5]. Initial work on nitride based HBTs focused on the AlGaN=GaN
material system [6­11], but the high ionisation energy of the Mg
acceptor in GaN [12] limits the effective hole density in the base layer,
severely restricting device performance. InGaN alloys, however, have
been shown to possess lower ionisation energies for the Mg acceptor
[13, 14], providing a pathway for higher base carrier densities and a

Source: Asbeck, Peter M. - Department of Electrical and Computer Engineering, University of California at San Diego

Collections: Engineering