Dennis John Eichorst

Influence of processing conditions on hillock formation in electron-beam evaporated platinum/titanium films

Abstract Hillock formation during annealing of Pt/Ti electrodes has been an obstacle in the development of ferroelectric memories. In order to minimize hillock formation, a factorial experiment was carried out to investigate the effects of deposition temperature, and oxide, titanium, and platinum thicknesses. The appropriate metal thicknesses for minimizing hillock formation was found to depend on deposition temperature. The developed model predicted best results for a deposition temperature of 200–250°C, Pt thickness of 2000–2500 A, and Ti thickness of ≤500A. Without substrate heating, both thin Ti (≤500A) and Pt (≤1000A) were required for reduced hillock formation. Pt strain levels and crystallite size distributions were also determined for the films. Strain level correlated with the occurrence of hillocks. In addition, a broad crystallite size distribution appeared to give smoother films.