Photoluminescence studies on radiation enhanced diffusion of dry-etch damage in GaAs and InP materials

We have investigated the radiation enhanced diffusion of ion defects during reactive ion beam etching of GaAs and InP, using the multiple quantum well (MQW) probe technique. During low energy (sub-keV) Ar+ ion exposure, illumination with light of energy above the band gap can substantially reduce the photoluminescence efficiency of MQW samples, relative to those which were not laser illuminated; the degradation of luminescence efficiency increases with the intensity of the light. Illumination with light of energy below the band gap produces a slight increase in the damage profiles. The observation of enhanced defect diffusion due to optical radiation in our studies suggests that in ion-assisted etching of semiconductors, the generation of excess electron-hole pairs and their subsequent recombination can play an important role in the propagation of defects into the substrate. (C) 1996 American Vacuum Society.