Hydrogenation of InP by phosphine plasma

Hydrogenation of an InP surface has been attempted by the glow discharge of phosphine (PH 3 ) gas diluted with Ar. Atomic P in the PH 3 plasma is effective in suppressing the preferential etching of P at the InP surface which occurs easily by the exposure to the H 2 plasma. The mirror surface of InP is found to be maintained after the plasma exposure even at 250°C. It is verified by secondary ion mass spectroscopy analysis that H atoms with a density higher than 1×10 18 cm -3 diffuse into the bulk InP to 500 nm in depth. An enhancement of the photoluminescence (PL) intensity occurs on the hydrogenated surface, and a complete recovery of the PL intensity is observed after annealing at 350°C for 3 min. In the case of exposure to the PH 3 and H 2 mixture plasma, an increase of the H 2 flow rate leads to further enhancement of the PL intensity which is attributed to the band bending at the surface due to an introduction of P vacancies.