Lattice site location of cadmium and tellurium implanted in gallium arsenide

1.5 or 1.8 MeV 4He+ channeling techniques were used to study the lattice location of Cd and Te atoms implanted in GaAs single crystals at various temperatures, the defects induced during implantation and their anneal characteristics. Angular scans through the major axes were used to assign the lattice location exactly. It was found that high substitutional fraction of Cd and Te atoms was obtained by implantation at 2000C-3000C, while most of Cd and Te implanted at room temperature were located on sites slightly displaced from lattice sites. It was observed that implantations through SiO2 or Si3N4 encapsulating films at 5000C and As-preimplantations were ineffective in obtaining high substitutional fraction and reducing defect density. (auth.)