Electrodes for ferroelectric thin films

Abstract

Abstract Platinum and ruthenium oxide (RuO2) deposited by ion beam sputter-deposition are evaluated for use as electrodes for PZT thin film capacitors. The effect of deposition temperature, film thickness, and the presence of oxygen on hillock formation in platinum is discussed. It is shown that the hillock density in Pt/Ti/SiO2/Si films can be significantly reduced by properly controlling the processing conditions and film thickness. Stress measurements correlate with the experimental observation that depositing thinner platinum films (<800 Å) is an effective means of reducing hillock formation. The use of an intermediate deposition temperature 200–250°C also helps minimize hillock formation. Diffusion of the Ti adhesion layer into and/or through the platinum was significantly reduced by replacing the Ti with a TiOx adhesion layer. RuO2 electrodes are compared to Pt in terms of resistivity, surface morphology, microstructure and film orientation. Key Words: electrodesRuO2 Hillocks