Effect of Ion Bombardment on the Chemical Reactivity of Gallium Arsenide(100)

The interaction of O-2 and H2O, over the exposure range 10(7)-10(13) langmuirs, with chemically cleaned (1:1 HCl/H2O) and Ar+-ion-bombarded (0.5-3 keV) GaAs surfaces has been studied by X-ray photoelectron spectroscopy. Ion-bombarded GaAs shows an increased chemical reactivity compared to that of chemically cleaned GaAs when exposed to O-2 and H2O. Ion-bombarded GaAs exposed to O-2 yields Ga2O3, As2O3, and As2O5; Ga2O3 being the major component. Exposure of chemically cleaned and ion-bombarded GaAs to H2O produces only peak broadening on the high binding energy side of the Ga 3d core level photopeak, indicating GaO(OH) formation at an exposure <10(11) langmuirs and both GaO(OH) and Ga(OH)(3) species at exposures greater than 10(11) langmuirs. However, the reactivity of the ion-bombarded material is greater than that of the chemically cleaned material. The results obtained in this study are compared with those for cleaved and annealed GaAs.