Interaction of trimethyl based metalorganic precursors on InSb(1 0 0)-c(8×2)

High resolution electron energy loss spectroscopy and X-ray photoelectron spectroscopy have been used to investigate the adsorption behaviour and thermal decomposition of trimethylaluminium (Me3Al), trimethylindium (Me3In) and trimethylgallium (Me3Ga) on the InSb(1 0 0)-c(8×2) reconstructed surface. All three precursors follow the same basic decomposition route, involving the sequential loss of Me groups from the surface and the incorporation of the group III element via a dimethyl and monomethyl intermediate. In the case of Me3Al, however, an additional decomposition route has also been identified at elevated temperatures, involving the formation of a CH2 intermediate via H abstraction from a Me group. A mechanism is proposed that accounts for these observations, taking into account the most recent structural model of the InSb(1 0 0)-c(8×2) surface and the different carbon–metal bond strengths of each precursor. In the case of Me3Al, the additional high temperature decomposition route and formation of surface >CH2 species occurs via an Al–C–Sb heterobridge intermediate. The strong Al–C bond suppresses complete Me ligand desorption and offers the possibility of the alternative decomposition route.