The effect of hydrogen passivation on electrical characteristics of double-polysilicon self-aligned bipolar transistors

摘要

The influence of hydrogen passivation using forming gas annealing (FGA), on the electrical performance of double-polysilicon self-aligned bipolar junction transistors was investigated. While the collector current remained essentially unaffectedafter FGA, the base current decreased substantially. As a result. the peak DC current gain increased by a factor of three. Identification of the various base current components showed that the SiO{sub}2/monosilicon interface area along the perimeter ofthe emitter window, were effectively 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 the peak cut-off frequency by up to 400％. This is explained by a decrease in emitter-base junction capacitance. which was verified experimentally.