Samples of S-doped n-type (100) material were implanted with 30keV 15N+ ions to doses of 1014 to 1016/cm2 at room temperature. The implanted samples were subjected to isochronal vacuum annealing at temperatures ranging from 450 to 650C. The annealing behavior of N atom distributions, implantation-induced displacements of In atoms, vacancy-type defects, and damage annealing were studied by using nuclear resonance broadening, secondary ion mass spectrometry, ion back-scattering and channelling, and slow positron annihilation techniques. Doses of more than 1015/cm2 were found to produce amorphous layers that extended to depths (of up to 110nm) that were beyond the deposited energy distribution. The depth of an amorphous layer was observed to depend upon the implantation dose. Temperature- and dose-dependent epitaxial re-growth that started from the amorphous/crystalline interface was observed at 575C. The damage and vacancy concentration distributions were correlated with the implanted N distribution, in the case of the highest implantation dose (1016/cm2). The disorder annealing and loss of N behaved in a similar manner with increasing temperature. Almost no redistribution or loss of N occurred at lower doses, in spite of structural damage and vacancy annealing. Interpretation of the positron data permitted the identification of 2 types of vacancy. The type of vacancy defect was found to depend upon the implantation dose and annealing temperature. Thus monovacancies were formed in the In sub-lattice at low implantation doses, while the highest dose produced divacancies. Annealing tended to convert the monovacancies into divacancies, which recovered at high temperatures; depending upon the implantation dose.

E.Rauhala, T.Ahlgren, K.Väkeväinen, J.Räisänen, J.Keinonen, K.Saarinen, T.Laine, J.Likonen: Journal of Applied Physics, 1998, 83[2], 738-46