M. Sanden et al., The effect of hydrogen passivation on electrical characteristics of double-polysilicon self-aligned bipolar transistors, SOL ST ELEC, 43(3), 1999, pp. 615-620
The influence of hydrogen passivation using forming gas annealing (FGA), on
the electrical performance of double-polysilicon self-aligned bipolar junc
tion transistors was investigated. While the collector current remained ess
entially unaffected after FGA, the base current decreased substantially. As
a result, the peak DC current gain increased by a factor of three. Identif
ication of the Various base current components showed that the SiO2/monosil
icon interface area along the perimeter of the emitter window, were effecti
vely passivated after FGA, both in the quasi-neutral base and in the space
charge region. The FGA treatment was also found to lead to an increase in t
he peak cut-off frequency by up to 40%. This is explained by a decrease in
emitter-base junction capacitance, which was verified experimentally. (C) 1
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