PREFERENTIAL SPUTTERING OF GAAS

Low-energy (0.65-3 keV) Ar+ ions were used to sputter (100) and (110) GaAs. Preferential sputtering effects were investigated by means of Auger electron spectroscopy. The results show that the equilibrium sputtered surface composition on both surfaces is depleted in As. No sample orientation effects were observed. However, the equilibrium compositions of the sputtered surfaces become increasingly Ga-enriched by increasing the energy of the bombarding ions. The sputtered surface composition is independent of the angle of incidence of the bombarding Ar+ ions. For the different experimental conditions, the mean final surface compositions varied from GaAs0.89 to GaAs0.69. These values are in broad agreement with other reported AES studies. This agreement is probably due to the fact that the sputtered surface composition is independent of the angle of incidence of the ions on the GaAs sample.