Quantitative AES and RBS depth profiles of titanium silicide films on GaAs after annealing

Abstract

Quantitative RBS and AES depth profiles of Tisi, contacts deposited on GaAs by co-sputtering in a magnetron system have been performed. The bulk composition and thickness of the films were determined by RBS. AES showed that some oxygen was incorporated in the silicide layer during the deposition procedure. Comparing the depth pro& provided by both techniques, preferential sputtering effects have been studied. It is shown that silicon is preferentially sputtered as a conseQuence of its segregation to the surface. Sputter yields of the compound ( YTLsil = 2.85 atoms ion-') and of the individual components ( = 3.1 atoms ion-') were also estimated for 3-keV Ar+ ions. Important interdBusion el€ects appear to occur at annealing temperatures above 600 "C. It is also observed that As has a higher mobility than Ga in TSi, when annealed at 800 "C. = 2.5 atoms ion-' and