Summary: 582 IEEE ELECTRON DEVICE LETTERS, VOL. 23, NO. 10, OCTOBER 2002
Implementation of Reduced Turn-On Voltage InGaP
HBTs Using Graded GaInAsN Base Regions
P. M. DeLuca, C. R. Lutz, R. E. Welser, T. Y. Chi, E. K. Huang, R. J. Welty, and P. M. Asbeck, Fellow, IEEE
Abstract--InGaP/GaInAsN double heterojunction bipolar tran-
sistors (HBTs) with compositionally graded bases are presented
which exhibit superior dc and radio frequency performance.
Reducing the average base layer energy gap and optimizing the
emitter­base (e­b) and base­collector (b­c) heterojunctions leads
to a 100-mV reduction in the turn-on voltage compared to a
baseline InGaP/GaAs process. Simultaneously grading the base
layer energy band-gap results in over a 66% improvement in the
dc current gain and up to a 35% increase in the unity gain cutoff
frequency. DC current gains as high as 250 and cutoff frequencies
of 70 GHz are demonstrated. In addition, the InGaP/GaInAsN
DHBT structure significantly reduces the common emitter offset
and knee voltages, as well as improves the dc current gain
temperature stability relative to standard InGaP/GaAs HBTs.
Index Terms--Bipolar transistor, GaInAsN, graded base,
InGaP/GaAs, heterojunction bipolar transistors (HBTs), turn-on

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

Collections: Engineering