6533b831fe1ef96bd129908e

RESEARCH PRODUCT

Annealing behaviour of aluminium-implanted InP

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The annealing behaviour of aluminium has been studied in single-crystal InP implanted with 40 and 120 keV 27Al+ ions. The implantation doses were 1 x 1015 and 1 x 1016 cm-2. The aluminium concentration profiles were determined by two techniques, Secondary ion mass spectrometry (SIMS) and the nuclear resonance broadening technique (NRB) which was used for checking purposes. The usability of the SIMS technique for profiling Al rich layers was studied. Significant inconsistencies were observed in the SIMS profiles with the high dose implanted samples. The 120 keV, 1 x 1016 cm-2 implanted samples were subject to annealing in argon atmosphere in the temperature range 380–600°C. Redistribution and a significant aluminium surface enrichment took place. The coefficients of Al migration were determined by fitting a concentration independent solution of the diffusion equation to the experimental depth profiles. The deduced activation energy and frequency factor for aluminium migration in implanted InP are 0.78 eV and 5.5 x 105 nm2 / s, respectively. The effect of defects on the Al migration is discussed. Rutherford backscattering (RBS) spectra measured along ‹100› channeling direction for 120 keV, 1016 cm−2 implanted samples indicated a loss of crystalline structure near the surface both in the as-implanted and in the annealed samples.