A significant degradation of current gain of InP/InGaAs/InP double heterojunction bipolar transistors
was observed after passivation. The amount of degradation depended on the degree of
surface exposure of the p-type InGaAs base layer according to the...
A significant degradation of current gain of InP/InGaAs/InP double heterojunction bipolar transistors
was observed after passivation. The amount of degradation depended on the degree of
surface exposure of the p-type InGaAs base layer according to the epi-structure and device structure.
The deposition conditions such as deposition temperature, kinds of materials (silicon oxide,
silicon nitride and aluminum oxide) and lm thickness were not major variables to aect the device
performance. The gain reduction was prevented by the BOE treatment before the passivation. A
possible explanation of this behavior is that unstable non-stoichiometric surface states produced by
excess In, Ga, or As after mesa etching are eliminated by BOE treatment and reduce the surface
recombination sites.