FEATURE SIZE EFFECTS ON SELECTIVE AREA EPITAXY OF INGAAS

We demonstrate the use of an ultrathin (almost-equal-to 5 nm) Si layer deposited on InP substrates as a mask in selective area epitaxy of InGaAs by metalorganic molecular beam epitaxy. Patterns of varying shapes and sizes, from 5 to 0.5 mum, were written on the mask by focused Ga ion beam and etched by Cl2. The growth rate of InGaAs was studied by scanning force microscopy using stripes with guard rings spaced as close as 0.5 mum from the stripes. A small increase in the growth rate was detected only when the feature size was lower than 5 mum, and the growth rate was not affected by the presence of the guard rings. This shows that precursor material is being transferred from the slow growing {111}-planes to the (100)-plane, and that migration of species from the Si mask to the growing areas is negligible.