LOCALIZATION AND MOBILITY OF OXYGEN IN MONOCRYSTALLINE GAAS BY CHANNELING-NRA

O-16 was implanted into monocrystalline GaAs. The maximum concentratio n was determined to be 2.2 x 10(19) cm-3 in a depth of 2.4 mum. The sa mples were tempered at 400 and 500-degrees-C for 10, 20, 30 and 40 min . The lattice location of the implanted oxygen was determined in combi ning the channeling technique with nuclear reaction analysis (CHANRA). Angular scans were performed in the (100> direction of GaAs using the O-16(d, po)O-17 reaction with an incident deuterium energy of 1.85 Me V. For the evaluation of the experimental data stopping power and ion flux distributions in the crystal channels were simulated as a functio n of the incident angle with the program MABIC (materials analysis by ion channeling) [1]. It was found that the oxygen is occupying interst itial and substitutional sites after implantation. Oxygen is disappear ing from the substitutional sites during thermal annealing and an equi librium of two interstitial sites, in the center of the channel and wi th an average distance of 0.06 nm from the lattice atoms is establishe d.