Microstructural Analysis and Electrical Property Studies on BaxSr1-xTiO3 Ferroelectric Thin Films

点击翻译按钮获取中文摘要

9711044 McKittrick The development of high quality ferroelectric thin films is one of the main challenges to achieving giga-bit storage capacity on dynamic random access memory (DRAM) devices. Bulk ferroelectrics such as BaTiO3 are well characterized; however, the ferroelectric properties of thin films are not understood at a fundamental or even technical level. The microstructural features such as grain size, grain orientation (polycrystalline vs. epitaxial), stoichiometry, thickness of the film, residual stress, dopant concentrations and surface roughness have not been systematically studied or characterized. In order to use ferroelectric thin films, they must be sandwiched between conductive electrodes. These electrodes have been found to be the source of current leakage, increasing fatigue and aging damage. To fully exploit the optimized thin film structures, a basic understanding of the electrode is also necessary. This two year proposal seeks to systematically investigate the microstructure-electrical property dependence of paraelectric BaxS l-xTiO3, for megabyte DRAM applications. The objectives of this work are fourfold: (A) to optimize a conductive oxide electrode for the deposition of the ferroelectfic films, (B) to quantify the role of stoichiometry, grain size, thickness, and residual stress in thin film ferroelectrics and optimize the electrical properties, (C) investigate the effect of adding donor dopants to BaxSrl-xTiO3 with the goal of improving the electrical properties and (D) to fabricate superlattice structures of BaTiO3 and SrTiO3 and correlate the microstructural features with the electrical properties. This work will be performed at UC-San Diego and the Institute of Physics in Ensenada, Mexico which have different but complementary facilities. ***