AN AES STUDY OF THE ROOM-TEMPERATURE OXIDATION OF TASIX AFTER BOMBARDMENT WITH AR+IONS OF DIFFERENT ENERGIES

Tantalum silicide films of ∼200 nm thick and composition TaSi2 were obtained by co‐sputtering in a Varian 3120 S‐gun magnetron system. The films were then introduced in an AES spectrometer and bombarded with Ar+ ions of different energies in order to obtain surfaces of different compositions as a consequence of preferential sputtering effects and their dependence on the energy of the primary ions. Lowering the energy of the Ar+ ions resulted in surfaces very rich in tantalum. The interactions of these surfaces with oxygen at low pressures (10−8−10−5 Torr) and at room temperature then have been studied comparatively by Auger electron spectroscopy. Reference experiments with pure Si and Ta allowed the comparison with those of the different silicide surfaces. It is found that the oxygen uptake depends on the Ta content so that the richer in Ta the surface is, the higher the O2 incorporation. Furthermore, the uptake rate at the different TaSix surfaces resembles better the measured rate for pure Ta than that observed for pure Si. It has been observed also that the oxidation of Si is enhanced over that of pure silicon in all the surfaces studied here. Besides, the enhancement depends on the tantalum content. Copyright © 1990 John Wiley & Sons Ltd.