The effects of dry etching-induced damage were studied by using the optically detected magnetic resonance technique. A depth resolution of up to 5nm was achieved in spin resonance experiments which were based upon GaAs/AlAs type-II (real-space indirect) quantum-well structures. The recombination centers which were introduced by dry-etching were found to decrease the intensity of the optically detected magnetic resonance signal from quantum-well excitons. A heavier bombardment was found to cause partial hetero-interface mixing, as deduced from a change in the g-values of the confined electrons. The results suggested that the diffusion of damage-induced defects created cation-site vacancy-interstitial pairs. The detection of defect resonance in the near-surface region was possible by using a 50nm film of lightly-doped GaAs in which shallow donor-acceptor pair luminescence served as a probe for optically detected magnetic resonance experiments.

Y.Mochizuki, M.Mizuta, A.Mochizuki: Materials Science Forum, 1995, 196-201 1927-32