Reactions of Thin Metal Films with Si or SiO2 Substrates

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.