S. Sheu et al., MODELING THE POST-BURN-IN ABNORMAL BASE CURRENT IN ALGAAS GAAS HETEROJUNCTION BIPOLAR-TRANSISTORS/, Journal of applied physics, 79(9), 1996, pp. 7348-7352
The base current of AlGaAs/GaAs heterojunction bipolar transistor subj
ected to a long burn-in test often exhibits an abnormal characteristic
with an ideality factor of about 3, rather than a normal ideality fac
tor between 1 and 2, in the midvoltage range, We develope an analytica
l model to investigate the physical mechanisms underlying such a chara
cteristic. Consistent with the finding of an experimental work reporte
d recently, our model calculations show that the recombination current
in the base has an ideality factor of about 3 in the midvoltage range
and that such a current is responsible for the observed abnormal base
current in heterojunction bipolar transistor after a long bum-in test
. Post-burn-in data measured from two different heterojunction bipolar
transistors are also included in support of the model. (C) 1996 Ameri
can Institute of Physics.