OMVPE grown GaInAs:C for HBTs

We have grown GaInAs:C by low pressure organometallic vapor phase epitaxy and observed that the hole concentration of such layers decreases upon growth of cap layers such as heterojunction bipolar transistor emitter layers. Two mechanisms were found to play a role: one is H repassivation of the CAs acceptors, the other a non-H related decrease in the concentration of CAs acceptors due to C changing site or to the formation of complexes involving CAs. Depending on the growth conditions of the cap layers (temperature, flow of group V sources), one or the other mechanism prevails.