Spectroscopic measurements indicated the presence of high H concentrations in liquid-encapsulated Czochralski-grown undoped wafers. The undoped material could be reproducibly annealed so as to be semi-insulating. The H could facilitate the formation of antisite defects and could introduce electrically active H-related defects. The behavior of annealed material was thought to arise from the neutralizing effect of H that was provided by the dissociation of H complexes during annealing. As well as neutralizing impurities and defects, the H introduced new H-related defects in the band-gap and could also activate the formation of complexes which involved PIn. It therefore played an important role in the charge-compensation process in semi-insulating material that was obtained by high-temperature annealing.

Hydrogen Neutralization Effect in Bulk n-Type LEC InP Materials. N.Sun, X.Wu, X.Wu, Y.Zhao, L.Cao, Q.Zhao, W.Guo, J.Zhang, K.Bi, T.Sun: Journal of Crystal Growth, 2001, 225[2-4], 244-8