Jin, Z.; Uchida, K.; Nozaki, S.; Prost, Werner; Tegude, Franz-Josef:

Passivation of InP-based HBTs

In: Applied Surface Science, Jg. Vol. 252 (2006) ; No. 21, S. 7664-7670
ISSN: 0169-4332
Zeitschriftenaufsatz / Fach: Elektrotechnik
Abstract:
The surface effects, the (NH4)(2)S and low-temperature-deposited SiNx passivations of InP-based heterostructure bipolar transistors (HBTs)have been investigated. The surface recombination current of InP-based HBTs is related to the base structures. The (NH4)(2)S treatment for InGaAs and InP removes the natural oxide layer and results in  sulfur-bonded surfaces. This can create surface-recombination-free InP-based HBTs. Degradation is found when the HBTs were exposed to air for 10 days. The low-temperature-deposited SiNx passivation of InGaAs/InP HBTs causes a drastic decrease in the base current and a  significant increase in the current gain. The improvement in the HBT performance is attributed to the low deposition temperature and the effect of N-2 plasma treatment in the initial deposition process. The SiNx passivation is found to be stable. S/SiNx passivation of InGaAs/InP HBTs results in a decrease in the base current and an increase in the current gain. The annealing process can cause the base  current to decrease further and the current gain increase.