Evolution of Grain Structure in Thin Film Reactions

点击翻译按钮获取中文摘要

9713439 Barmak It is the objective of this research to understand the kinetics of thin film reactions and the morphology of associated product microstructures. The focus is on two prototypical systems, Ti/Al and Nb/Al. The former system is of importance in semiconductor metallization schemes while the latter is a simpler model system with qualitatively similar reaction kinetics. Studies include the reactions of Ti and Nb with pure A1 and the effects of Cu in A1 on phase reactions in these systems given the importance of Cu alloying in mitigating electromigration failure in integrated circuits. Reaction kinetics are investigated by differential scanning calorimetry (DSC) and the microstructure of reactant and product phases by transmission electron microscopy (TEM). TEM studies are used to correlate the location of product phase nucleation sites with the microstructural features of the reactant layers, such as triple junctions. Partially reacted samples are examined in cross section by high resolution analytical electron microscopy (AEM) to measure the composition profiles in the reactants and products at various times and to clarify the effect of reactant and product grain boundaries on the progress of the reaction. Complementary analytical calculations and simulations are used to interpret the experimental results. These include a kinetic model of phase formation based on coupled rate equations and a lattice model of phase growth and impingement which permits the determination of space-time correlations in evolving microstructures. %%% This research on the kinetics of microstructure formation in thin films is important to the application of metallic films in the magnetics and electronics industries. ***