Temperature dependent study of carbon-doped InP/InGaAs HBT's

We report on a temperature dependent study of the dc and the microwave performance of carbon-doped InP/In/sub 0.53/Ga/sub 0.47/As heterojunction bipolar transistors (HBT's). The turn on voltage increased 114% and the dc current gain decreased 25% as the temperature was reduced from 300 K to 33 K. Under high-current injection, there was a 29% increase in the current gain cutoff frequency of these devices as the temperature was lowered from 300 K to 77 K. By investigating the operation of HBT's at cryogenic temperatures, increased understanding of the mechanisms of carrier transport in these devices can be obtained, and this may lead to improvements in device performance.