X-ray photoelectron spectroscopic and atomic force microscopic study of GaAs etching with a HCl solution

GaAs(100) substrates covered with native oxides have been etched with a HCl solution for 10–20 min and subsequently rinsed with water for several seconds. The surface of the GaAs substrate thus prepared has been examined with atomic force microscopy. The surface flatness is improved by this wet etching and the surface undulation remains within a ± 1 monolayer fluctuation over a 1 μm × 1 μm surface area. X-ray photoelectron spectroscopy has been used to examine the chemical composition of the GaAs(100) surfaces after the HCl/H2O wet etching sequences. UV photoirradiation of the GaAs surface treated with the HCl solution has been performed to characterize the chlorides on the GaAs surface.