The effect of Se and Zn pre-deposition on thermal diffusion of elements across the ZnSe/GaAs interface studied by SIMS

ZnSe samples were grown on Zn and Se pre-deposited GaAs substrates. Thermal diffusion of elements across the ZnSe/GaAs interface was investigated, using secondary ion mass spectroscopy (SIMS). Diffusion of Ga atoms across the interface was observed for Zn pre-treated substrates, whereas Se pre-treatment of the GaAs substrate prevents thermal diffusion of Ga across the interface. This effect believed to be due to formation of GaAsxSey ''barrier layers'' at the ZnSe/GaAs interface. The Ga diffusion coefficients at annealing temperatures of 400, 500 and 600 deg. C were found to be 2.1x10-16, 1.9x10-15, and 2.2x10-14 cm2/s, respectively. The thermal diffusion of other elements across the interface was not observed within the depth resolution limit of SIMS analysis