PNNL

Abstract

(Ba,Sr)TiO3 (BST) thin films have been grown on planar Ir/Si and Pt/Si substrates and on 3D Ir electrodes by metalorganic chemical vapor deposition (MOCVD) using two kinds of Beta diketonate-based BST precursors. Film growth was studied as a function of film thickness, composition, and substrate temperature. Growth rate was monitored by in-situ by a variety of techniques including x-ray photoelectron spectroscopy, Auger electron microscopy, atomic force microscopy, transmission and scanning electron microscopy, x-ray diffraction, and impedance analyzer. The results reveal that the two sets of BST precursors, albeit slightly different, show quite different reactvities that strongly affect the step coverage on the 3D structure. However, different reactivities have no apparent effect on the microstructure, surface morphology, and dielectric properties of the stoichiometric BST films. These properties strongly depend on the film composition, substrate material and growth temperature. in general, the BST films grown on Pt exhibit better crystalline quality, surface smoothness, and dielectric properties compared to those grown on Ir under the optimal growth conditions.