A study was made of H-related metastable defects in n-type material, and of their relationship to the EL2 center. It was found that the M3 and M4 defects were observed only in crystals which contained the EL2 center in the as-grown state after exposure to H plasma. The EL3 level, which was tentatively attributed to off-center O, could not be responsible for the formation of the defects. It was suggested that both diffused H and the pre-existing As antisite, or its related defects, were responsible for the formation of the M3/M4 defects. A quantitative analysis of samples which had been exposed to atomic H showed that the M4 defect consisted of 2 different configurations. A metastable component of the M4 defect which coupled with the M3 defect was not formed or was latent in the as-irradiated state at room temperature. The M3/M4 couple was formed after bias annealing at 420K.

Role of the EL2 center in the formation of metastable hydrogen-related defects in n-GaAs T.Shinagawa, T.Okumura: Japanese Journal of Applied Physics - 1, 1998, 37[4A], 1939-44