Mechanism of low energy S+ ion bombarded p-GaAs (100)

X-ray photoelectron spectroscopy (XPS) and low energy electron diffraction (LEED) have been used to characterize the chemical structure and site location of sulfur atom on p-GaAs (100) treated by bombardment of low energy S+ ions over the range from 10 to 100 eV. S+ ion bombardment resulted in the formation of Ga–S and As–S species on GaAs surface. It was found that the S+ ions with energy above 50 eV were more effective in formation of Ga–S species, which assisted the GaAs (100) surface in reconstruction into an ordered (1 × 1) structure upon annealing. After taking into account physical damage due to the process of ion bombardment, we found that 50 eV was the optimal ion energy to form Ga–S species in the sulfur passivation of GaAs (100). The subsequent annealing process removed both donor and acceptor states that were introduced during the ion bombardment of GaAs, and resulted in a sharp (1 × 1) LEED pattern.