Improvement of (Pb1−xLax)(ZryTi1−y)1−x/4O3 ferroelectric thin films by use of SrRuO3/Ru/Pt/Ti bottom electrodes

Abstract

This work deposits (Pb1−xLax)(ZryTi1−y)1−x/4O3 (PLZT) thin films, possessing good ferroelectric properties (Pr=14.4 μC/cm2), on Pt/Ti/SiO2/Si substrates, using SrRuO3 perovskite as bottom electrodes. Precoating a metallic Ru layer on Pt/Ti/SiO2/Si substrates prior to depositing SrRuO3 bottom electrode further improves the film electrical properties. The optimum ferroelectric properties achieved are Pr=25.6 μC/cm2, Ec=47.1 kV/cm, and εr=1204. Analyzing the elemental depth profiles using secondary ions mass spectroscopy reveals that the presence of the metallic Ru layer effectively suppresses the outward diffusion of Ti and Si species. The interdiffusion between the SrRuO3 layer and the subsequently deposited PLZT is also substantially reduced, an effect that is presumed to be the primary factor in improving ferroelectric properties for PLZT thin films.