Epilayers of ZnSe were grown onto GaAs substrates which had been treated with Se and Zn before growth, and the diffusion of elements across the interface was investigated by using secondary ion mass spectroscopy. Ion-implanted standards were used to calculate the useful ion yield for Zn and Se in the GaAs matrix and for Ga and As in the ZnSe matrix. The diffusion of Ga atoms across the interface was observed in Zn pre-treated substrates. A comparison study showed that Se pre-treatment of the GaAs substrate prevented thermal diffusion of Ga across the interface. This effect was believed to be due to the formation of GaAs-Se layers, at the interface, which acted as a diffusion barrier. The Ga diffusion coefficients at annealing temperatures of 400, 500 and 600C were equal to 2.1 x 10-16, 1.9 x 10-15 and 2.2 x 10-14cm2/s, respectively. Thermal diffusion of other elements across the interface was not observed within the resolution limit of secondary ion mass spectrometry.

Quantitative Study of Thermal Diffusion of Elements across a ZnSe/GaAs Interface using SIMS. F.S.Gard, J.D.Riley, R.Leckey, B.F.Usher, K.Prince, P.Burke: Surface Review and Letters, 2001, 8[1-2], 33-42