High-resolution X-ray photo-emission spectroscopy and Ar ion bombardment were used to study temperature-dependent chemical reactions and species redistribution in the Ti/GaAs(100) system. The results showed that Ti, deposited at room temperature, disrupted the GaAs substrate (by reacting with As) and released Ga into the over-layer. The As was found to accumulate, near to the buried interface, in the form of a Ti-As compound. The Ga was depleted, but accumulated beyond the reaction region. Sputter depth profiles indicated that high-temperature annealing caused Ti diffusion into the GaAs substrate and enhanced reaction with As. The rejection of Ga from the forming Ti-As compound became more severe when the amount of Ti-As increased. Heating promoted the segregation of rejected Ga atoms to the vacuum surface, but had little effect upon As segregation.

F.Xu, D.M.Hill, Z.Lin, S.G.Anderson, Y.Shapira, J.H.Weaver: Physical Review B, 1988, 37[17], 10295-300