PHOTOLUMINESCENCE AND X-RAY PHOTOELECTRON-SPECTROSCOPY STUDY OF S-PASSIVATED INGAAS(001)

The influence of sulfur passivation on the surface composition of In0. 53Ga0.47As(001) was investigated with photoluminescence (PL) and x-ray photoelectron spectroscopy (XPS). Films of In0.53Ga0.47As(001), epita xially grown on InP(100) substrates, were S passivated using a dry ele ctron cyclotron resonance (ECR)-plasma deposition process and were eit her passivated as-prepared, or exposed to a BCl3 pre-etch prior to pas sivation. In the spectral range from 1450 to 1750 nm, S passivation en hances the PL yield by approximately an order of magnitude. XPS shows that S binds both to In and As, although preferably to In, and that ox idation is essentially eliminated by the passivation process. The In-S bonds are more stable upon annealing than are the As-S bonds. Further more, the pre-etched + H2S treatment enhances the PL yield beyond that of the H2S passivation treatment alone and produces a higher ratio of In-S to As-S bonds at the surface. In a second set of experiments, th e influence of the ECR power applied to the sample during passivation was examined. The variation of this processing parameter has little ef fect on the surface composition. (C) 1996 American Institute of Physic s.