The lattice sites of implanted Te in hetero-epitaxial nitride films, grown onto sapphire substrates, were studied. The samples were implanted with 400keV 130Te ions, at 300C, to a dose of 1.5 x 1015/cm2. The samples were analyzed by using Rutherford back-scattering spectrometry channelling, with 2MeV 4He ions. The maximum Te concentration was equal to 0.2at%. On the basis of measured channelling angular scans for Ga and Te along the <00•1> and <10•1> axial directions it was concluded that, in as-implanted samples, some 70% of the Te atoms were located on Ga atom lattice sites, but were slightly displaced. The measured <10•1> scans revealed no evidence of substitutional Te on N lattice sites. Post-implantation annealing (900C) was found to decrease the substitutional fraction of Te, while little recovery of the host lattice was observed. This indicated the occurrence of an interaction between Te atoms and implantation-produced lattice defects. No Te migration was observed during annealing at 900C. The effect of misfit dislocations, in the host lattice, upon the channelling yield was visible in <10•1> angular scans which were performed at a tilt angle of 47°.

Lattice Location of Implanted Tellurium in GaN Heteroepitaxial Films. A.Seppälä, E.Rauhala, R.Grötzschel: Journal of Physics D, 2001, 34[3], 269-72