A study on the transient effect due to hydrogen passivation in InGaP HBTs

The transient effect of InGaP heterojunction bipolar transistors is studied. The current gain increases with V/sub BE/ bias and becomes stable after several sweeps. The time to reach steady state depends on the collector current I/sub C/ and the ambient temperature. A new electrical method was introduced to calculate the passivation ratio, which is defined as the number of donor hydrogen (H/sup +/) atoms divided by the number of negatively charged carbon atoms (C/sup -/) in the heavily doped base layer. A passivation ratio of 69.98% obtained by this method agrees very well with that measured by secondary ion mass spectrometry of 69%.