FERROELECTRIC BISMUTH TITANATE FILMS BY HOT-WALL METALORGANIC CHEMICAL-VAPOR-DEPOSITION

Ferroelectric bismuth titanate thin films were successfully deposited on Si, sapphire disks, and Pt/Ti/SiO2/Si substrates by hot wall metalo rganic chemical vapor deposition. Triphenyl bismuth [Bi(C6H5)3] and ti tanium ethoxide [Ti(C2H5O)4] were used as the precursors. The depositi on rates were in the range of 3.9-12.5 nm/min. The Bi/Ti ratio was eas ily controlled by precursor temperature, carrier gas flow rate, and de position temperature. As-deposited films were pure Bi4Ti3O12 phase. Th e films were specular and showed uniform and fine grain size. Optical constants as a function of wavelength, were calculated from the film t ransmission characteristics in the ultraviolet-visible-near infrared ( UV-VIS-NIR) region. The 550-degrees-C annealed film showed a spontaneo us polarization of 26.5 muC/cm2 and a coercive field of 244.3 kV/cm.