Interdiffusion and precipitation in Al[sbnd]Hf thin-film couples

Abstract

Aluminium-transition-metal alloy films are of great technological value in microelectronics. We have studied the solute effect of Cu on the interdiffusion and compound formation in Al[sbnd]Hf thin-film couples and found that Cu solute decreases the activation energy of the growth of Al₃Hf and influences the microstructure and the smoothness of the reaction interface. Copper is found to segregate at the grain boundaries of Al, retarding grain growth of A1 and reducing discontinuous precipitation of Al₃Hf. In addition, it forms a defect structure in the tetragonal Al₃Hf which accelerated interdiffusion and growth of continuous Al₃Hf layers.