Electron stimulated reactions in thin GaAs oxide films have been investigated by x‐ray photoelectron spectroscopy. Thin oxide layers (≊0.7 nm) were grown on GaAs (1̄1̄1̄) surfaces at room temperature and excited oxygen exposures (107 L). The reactions were activated by irradiation of the oxide layer by an electron beam of extended area. The electron energy was allowed to vary between 10 and 120 eV while the current density was kept constant. The electron irradiation results in the breaking of the donor–acceptor As=O bond observed as a reduction of As2O5 to As2O3. The behavior of As2O5 and As2O3 spectra areas with the incident electron energies demonstrates that the breakage of the As=O bond is consistent with an Auger decay model. Furthermore, the electron irradiation also originates an increase of the As suboxide. However, a peculiar inhibition of the suboxide growth is produced for energies corresponding to the As and Ga 3d or oxygen 2s core level binding energies.