Hydrogenation effects on AlGaAs/GaAs heterojunction bipolar transistors

A comparison of the effects of H-2 and D-2 plasmas on the dc characteristic s of AlGaAs/GaAs heterojunction bipolar transistors showed a strong influen ce of exposure time, ion flux and ion energy on the forward and reverse jun ction current-voltage (I-V) characteristics, base resistance and emitter-ba se junction breakdown voltage and ideality factor. The results are quite di fferent than those observed with N-2 or Ar plasma exposure of similar devic es and show that passivation of the carbon acceptors in the base layer is a major problem with processes such as plasma enhanced chemical vapor deposi tion of SiNx or SiO2 sidewall space layers during HBT fabrication. (C) 2001 Published by Elsevier Science Ltd.