Reactions of Thin Metal Films with Si or SiO₂ Substrates

Abstract

The changes in vacuum-evaporated films of Ti, V and Mb on Si and SiO₂ substrates after thermal anneals are investigated by backscattering and by x-ray spectrometry. Backscattering analysis provides the relative atomic composition as a function of depth with high sensitivity. Glancing angle x-ray spectrometry detects the chemical composition with high specificity. Combined, the two methods create a specific picture of the transformations induced in the films by the thermal treatment. Generally the reaction on a pure Si substrate produces a Si-rich silicide, and on a SiO₂ substrate a metal-rich silicide in the form of an intermediate layer largely free of oxygen. The oxygen originally bound to the Si in the SiO₂ is transferred to the remaining metal layer. Residual oxygen “in the metal film and metal oxides on the metal film influence the silicide formation.