Ferroelectric Thin Films from Metallo-organics: The Influence of Different Atmospheres during RTA Processing

Abstract

Barium Titanate (BaTiO₃) films have been deposited on platinum via spin-casting metallo-organic compounds and rapid thermal annealing (RTA). This method, called metallo-organic decomposition (MOD), produces tetragonal BaTiO₃ films with easily controllable stoichiometry as determined by x-ray diffraction (XRD) and Auger electron spectroscopy (AES). The precursors used were barium neodecanoate and titanium dimethoxy dineodecanoate. The film precursor is obtained by mixing the individual precursors in a nearly 1∶1 molar ratio before processing. Variable thickness (0.1–3 µm) is achieved by spin-casting multiple layers of the films. The films were RTA processed to 650° for 30s or to 950° for 15s under controlled atmosphere (O₂, Ar, and partial vacuum). The films processed under O₂ showed better stoichiometry and purity than the ones processed under partial vacuum (10⁻³ Torr) as evidenced by XRD and AES. The carbon contamination from pyrolysis residues, prevalent in the partial vacuum processed films, fell below the instrument detection limit for the O₂ and Ar processed films. All the films are uniform and crack-free as shown in the scanning electron micrograph (SEM). Average grain size determined by SEM ranged from 0.01 µm to 0.5 µm, depending on the annealing condition.