STRUCTURE AND PROPERTIES OF EPITAXIAL BA0.5SR0.5TIO3 SRRUO3/ZRO2 HETEROSTRUCTURE ON SI GROWN BY OFF-AXIS SPUTTERING/

We report the growth and characterization of epitaxial Ba0.5Sr0.5TiO3/ SrRuO3/ZrO2 on Si for potential charge storage applications. Both Ba0. 5Sr0.5TiO3 (BST) and SrRuO3 (SRO) are grown (110)-oriented on yttrium- stabilized ZrO2 (YSZ) (100)-buffered Si. These films show a high degre e of crystallinity with minimal interdiffusion at the interfaces as ev idenced from x-ray diffraction, Rutherford backscattering, and transmi ssion electron microscopy. Studies on the in-plane crystallographic re lations between the layers revealed an interesting rectangle-on-cube e pitaxy between BST/SRO and YSZ. The dielectric constant and loss tange nt of the BST dielectric layer are 360 and 0.01 at 10 kHz, respectivel y. The leakage current density is lower than 4X10(-7) A/cm(2) at 1 V. A strong frequency dependence on both dielectric constant and loss tan gent is observed in 1-10 MHz frequency range. This is attributed to th e effect of a series resistance in the measurement loop, which is like ly related to the bottom SrRuO3 electrode. (C) 1995 American Institute of Physics.