Ion erosion induced nanostructured semiconductor surfaces

We consider nanostructures formed on semiconductor surfaces of Si(100), InP(100) and GaAs using medium energy (50–100 keV) Ar+–ion beam sputtering. The issues of dependence of nanostructure formation on these semiconductor substrates on ion–energy, –fluence, –flux, angle of incidence, and crystallographic orientation are addressed. The threshold fluence for formation of nano–islands on Si(100) implanted with normally incident 50 keV Ar+–ions was found to be 2 × 1017 ions/cm². For InP(100) implanted with 100 keV Ar+–ions an increase in angle of incidence results in decrease of surface roughness. Surfaces of GaAs(100) and GaAs(111) implanted with normally incident 50 keV Ar+–ions show nanopits of density 3–4 × 109/cm². The existing theories are applied to explain the formation of observed surface nanostructures.