Defects Induced by Wafer Processing and Thermal Treatment in InP Probed with Monoenergetic Positrons

Variable-energy positron-beam studies have been made on InP single crystals. Doppler broadening profiles of the positron annihilation and the mean diffusion length of positrons were found to be sensitive to defects under the subsurface region. For a specimen after high-quality polishing, vacancy-type defects with a concentration of 1018 cm-3 were observed in the range of 0∼400 nm. For the specimen after heat treatment, a damaged layer introduced by dephosphorization was observed. An overlayer containing monovacancies, with a thickness of 140 nm, was found to be formed after 450°C annealing.