The de-activation mechanism of C acceptors was systematically studied by measuring the annealing behavior and depth profile of the carrier concentration. It was found that H impurities dominated C de-activation. Their de-activation involved 2 steps: H donors which were isolated from C acceptors compensated C, and H impurities neutralized the C by forming neutral C-H complexes. The compensating H donors diffused out extremely rapidly at relatively low temperatures. This was thought to be the first report of the presence of isolated H donors in heavily C-doped GaAs. The dissociation of C-H complexes was much slower than reported. The mechanism was explained in terms of H re-trapping by C.

H.Fushimi, K.Wada: Journal of Crystal Growth, 1994, 145[1-4], 420-6