Ga-terminated Surfaces Research Articles

Atomic structure of reconstructed group IV and III–V semiconductor surfaces

A review of recent progress in the understanding of structural and electronic properties of the low-index surfaces of group IV and III–V semiconductors is given and the “driving forces” for surface reconstruction are analyzed. The main conclusions from this study are that for group IV materials the reconstructions are always characterized by an increase in the bonding order at the surface. In contrast, for group III–V compounds the reconstructions are driven by substantial rehybridizations of dangling-bond orbitals and, simultaneously, by a tendency to lower the polarity of the surface. In some cases, such as the Ga-terminated (111) and As-terminated (100) surfaces of GaAs, the latter effect leads to an increased dangling-bond density at the reconstructed surface as compared to that on the ideal and unreconstructed surface.

Desorption of triethylgallium during metalorganic molecular beam epitaxial growth of GaAs

The desorption of triethylgallium (TEGa) adsorbed on As- and Ga-terminated surfaces during metalorganic molecular beam epitaxial (MOMBE) growth of GaAs is investigated by measuring the As flux dependence of the growth rate. The growth rate decreases with decreasing As flux in the substrate temperature range where the desorption of triethylgallium adsorbed on the growth surface occurs. This indicates that adsorbed TEGa (adTEGa) molecules desorb more rapidly on the Ga-terminated surface than on the As-terminated surface. To investigate the adTEGa desorptions on As- and Ga-terminated surfaces independently, the growth rates in alternating TEGa-As4 supply mode are compared with those in simultaneous supply mode. The growth rates in the alternating supply mode become smaller than those in the simultaneous supply mode as the substrate temperature is raised above 500 °C. This result demonstrates that the adTEGa desorption rate on the Ga-terminated surface is larger than that on the As-terminated surface.