Lattice location of implanted tellurium in GaN heteroepitaxial films

The lattice site of implanted tellurium in gallium nitride heteroepitaxial films grown on sapphire substrates has been studied. GaN samples were impla nted with 400 keV Te-130 ions at 300 degreesC. The ion dose was 1.5 x 10(15 ) cm(-2). The samples were analysed with Rutherford backscattering spectrom etry channelling using 2.0 MeV He-4 ions. The maximum Te concentration was 0.2 at.%. Based on measured channelling angular scans for Ga and Te along t he [0001] and [10(1) over bar1] axial directions, analysed by comparison wi th Monte Carlo simulations, it was concluded that in the as-implanted sampl e about 70% of Te atoms were on the Ga atom lattice sites, slightly displac ed. The measured [10(1) over bar] scan showed no evidence of substitutional Te on N lattice site. The post-implantation annealing at 900 degreesC was found to decrease the substitutional fraction of Te while little recovery o f the host lattice was observed. This indicates an interaction process betw een Te atoms and implantation-induced lattice defects. No migration of Te d uring annealing at 900 degreesC was observed. In addition, the effect of mi sfit dislocations in the host lattice on the channelling yield was visible in the [10(1) over bar1] angular scan measured at a 47 degrees tilt angle.