HYDROGEN PASSIVATION DURING COOLING OF PARA-TYPE INP GROWN BY METALORGANIC VAPOR-PHASE EPITAXY, DUE TO A COMBINED REACTION BETWEEN PHOSPHINE AND DIMETHYLZINC

Epitaxial layers of p-type InP, doped with zinc at a concentration of 2×1018 cm-3, were grown by metalorganic vapour phase epitaxy (MOVPE), using trimethylindium, phosphine and dimethylzinc. The samples were cooled after growth under different gas ambients, and passivation of the zinc acceptors was observed for samples cooled under gas mixtures containing phosphine. Hydrogen was detected by secondary ion mass spectrometry (SIMS) in the passivated layers. The source of atomic hydrogen was identified as the pyrolysis of phosphine, which was found to be enhanced by the presence of dimethylzinc. The importance of this finding to the reaction mechanism of MOVPE is discussed. © 1990.