Combinatorial study of the crystallinity boundary in the HfO2–TiO2–Y2O3 system using pulsed laser deposition library thin films

HfO2–TiO2–Y2O3 is an interesting high-k dielectric system, with the potential for higher values of k than the end members. Combinatorial library films of this system enable the study of the role of composition on phase formation as well as optical and mechanical properties. A library film of this system deposited at 400 °C exhibited a boundary line evident visually as well as in characterization. Mapping X-ray analysis showed the line corresponds to a crystallinity boundary, separating an amorphous phase and a face-centered cubic crystalline phase of yttrium hafnium oxide. Mapping nanoindentation across the boundary also revealed a sharp change in mechanical properties. The combinatorial technique is a powerful tool for high-throughput materials science, and by realizing this particularly unique pulsed laser deposition library film, allows many interesting materials phenomena and properties to be measured.