Formation and transformation of titanium-disilicide thin films on silicon substrates.

摘要

Owing to their low resistivity and high thermal stability, refractory metal silicides are being used in advanced integrated-circuit metallizations. The reliable incorporation of these materials in integrated circuits requires a detailed study of the relationship between thin-film properties, microstructure, and processing. The main purpose of the present study is to determine and to explain changes in the microstructure and properties of one material--titanium disilicide, TiSi;Motivated by numerous ambiguities in previous studies, we use transmission electron microscopy to determine the phases that form prior to the equilibrium TiSi;Silicides come in contact with other solids and gases at elevated temperatures during circuit fabrication. Consequently, reactions can occur that transform the phases present. In this work, we construct metal-Si-O, Ti-Si-N, Ti-Si-Al, and Ti-Al-N phase diagrams to explain ternary reactions involving metallization layers. When free energy data are unreliable or unavailable, we demonstrate how judicious use of the Gibbs phase rule allows the determination of stable tie-lines in these phase diagrams from a small number of thin-film reactions.;Having examined the initial formation of TiSi;As a summary, we bring together our studies of TiSi