Enhanced damage due to light in low-damage reactive-ion etching processes

Enhanced dry-etch damage in GaAs/GaAlAs and InGaAs/InAlAs quantum well structures due to additional illumination in low-power reactive-ion etching environments has been studied. We observed that damage in shallow quantum wells is increased significantly when above band-gap laser illumination is present during etching, although there is no measurable effect for illumination subsequent to etching. Contributing factors include the influence on ion channeling and also to a form of radiation-enhanced diffusion. The study shows that the effective defect diffusion coefficient is constrained to lie within the range 10(-15) to 10(-14) cm(2)/s. (C) 2000 American Institute of Physics. [S0003- 6951(00)01820-9].