The role of a conductive CaRuO3 bottom electrode for ferroelectric BaTiO3 films on a Si substrate

Abstract

A capacitor of Pt/BaTiO3/CaRuO3 (Pt/BTO/CRO) was successfully prepared on a Si substrate by using radio-frequency (RF) magnetron sputtering. The preferentially (110)-oriented CRO bottom electrode enabled us to obtain highly oriented BTO thin film on the Si substrate. Local epitaxy between BTO and CRO was clearly confirmed by high resolution transmission electron microscopy (HRTEM) and fast Fourier transformation (FFT) analysis. The clear interface between CRO and BTO without any Si diffusion and silicate formation was determined by Auger electron spectroscopy (AES). The polarization value (2P(r)) of 6 mu C/cm(2), the coercive field (2 vertical bar E-c vertical bar) of 61 kV/cm and the stable current density of 1 x 10(-8) A/cm(2) around 2100 kV/cm electric field were obtained. Its tunability on CRO was reached up to 0.52 with a loss tangent less than 0.09 at room temperature. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim