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Auger spectroscopy of the electron-stimulated absorption of oxygen on surfaces of polycrystalline aluminum

“…Our result agrees with [1], where it was shown that the chemical composition of the surface stabilized at oxygen deposition doses of ~300 L. In [2], stabiliza tion of the chemical content corresponded to oxygen deposition doses of no more than 3 L from the residual atmosphere. The authors of [2] explained this consid erable contradiction of the literature data by noting that under low partial pressure, oxygen can be supplied to the oxidizing area not only via deposition from the residual atmosphere, but by other mechanisms as well, e.g., due to the diffusion of oxygen atoms from areas on the surface of the sample beyond the zone of ionic etching. In our case, as was mentioned above, the effect of the electron probe and oxygen from untreated areas on the surface was not considered.…”

“…According to the literature data, the oxidization of aluminum under a partial oxygen pressure of 10 -6 mm Hg can be condi tionally divided into three stages [1,2]: At the first stage (the dose of deposited oxygen is as high as 10 L), atoms are suspended over the surface, and the distance from the oxygen atoms to the plane of the aluminum atoms depends strongly on orientation of this plane. At the second stage (up to 50 L), there is chemisorption of oxygen with the oxygen being incorporated in the interstitial voids of the aluminum, and the oxygen is apparently drawn into the surface volume.…”