Electrical and optical properties of amorphous BaTiO3 thin films grown by metalorganic chemical vapor deposition on indium tin oxide-coated glass

Abstract

In order to fabricate insulating films for a full-color thin-film electroluminescent display, an amorphous BaTiO3 thin film was deposited on an indium tin oxide-coated soda lime glass substrate at a low substrate temperature by metalorganic chemical vapor deposition with use of Ba(tmhd)2, Ti(OC3H7)4 and N2O. Scanning electron microscopy of the tilted surface of the as-grown BaTiO3 film showed a surface morphology of granular-like micrograins without defects such as pinholes and clusters. The thickness of the as-deposited film was approximately 1400 ？ as confirmed by cross-sectional transmission electron microscopy. The formation of an interface film between the as-grown film and the indium tin oxide was not observed. Room-temperature frequency dependence of capacitance and dissipation factor was clearly indicated those typically exhibited by the amorphous BaTiO3 capacitor deposited on the conducting substrates having a metal-insulator-metal (MIM) structure. Optical transmittance measurements showed that the amorphous BaTiO3 film deposited at 400°C on the indium tin oxide-coated glass substrate has the transparency of about 80% in the visible wavelength range. Furthermore, the value of the optical band gap was approximately 4.71 eV. These results indicate that the amorphous BaTiO3 thin film grown on the indium tin oxide-coated glass can be used for thin-film flat panel electroluminescent display applications. ？ 1994 IOP Publishing Ltd.