A lengthy review was presented of the characterization of defects in these materials by using positrons. It was recalled that, during the past few years, there had been a rapid increase in the use of positron annihilation spectroscopy of the overlayers, interfaces, and buried regions of semiconductors. This was because there were few other techniques which were so sensitive to low concentrations of open-volume type defects. The characteristics of the annihilation gamma rays depended strongly upon the local environment of the annihilation sites and were used to probe defect concentrations in ranges which were inaccessible to conventional defect probes. It was shown how positron annihilation spectroscopy could be used as a non-destructive probe for the examination of defects in technologically important Si-based structures. Attention was focused on the quality of overlayers, the formation and annealing of defects after ion implantation, the identification of defect complexes, and on the evaluation of the distribution of internal electric fields. Investigations of the activation energy for the de-trapping of H from SiO2/Si interface trap centers were described, as well as studies of variations in interface trap density, hole trapping at SiO2/Si interfaces, and radiation damage in SiO2-Si systems. A brief summary was also given of the application of the technique to compound semiconductors.

P.Asoka-Kumar, K.G.Lynn, D.O.Welch: Journal of Applied Physics, 1994, 76[9], 4935-82