Formation of nearly defect-free nanoripples by sputtering of GaAs (001) surface at high temperature

Abstract The evolution of GaAs (001) surface morphology by normal incidence 1 keV Ar+ ion sputtering at high temperature has been investigated for different temperature and ion fluence. An anisotropic surface modulation is observed above the substrate recrystallization temperature ∼300 °C. With increase of sputtering time, they evolve into highly ordered and almost defect-free ripple-like structure consisting of alternate arrays of elongated terraces and nano-grooves with ridges along the 1 ¯ 0> direction. Such surface instability is attributed to the effect of anisotropic surface diffusion of vacancies in the presence of Ehrlich–Schwoebel barrier. The amplitude and wavelength of the ripple show a power law increase with sputtering time and finally saturate at longer time irradiation.