METALORGANIC CHEMICAL-VAPOR-DEPOSITION OF FERROELECTRIC PB(ZR,TI)O3 THIN-FILMS

Ferroelectric Pb(ZrxTi1-x)O3 films were successfully and reproducibly deposited by both hot-wall metalorganic chemical vapor deposition (MOC VD) and cold-wall MOCVD. One of the important problems associated with the MOCVD techniques is the selection of ideal precursors. after an i ntensive investigation for the most suitable precursors for MOCVD PZT films, the safe and stable precursors, namely lead tetramethylheptadio ne [Pb(thd)2], zirconium tetramethylheptadione [Zr(thd)4], and titaniu m ethoxide [Ti(OEt)4], were chosen. The films were deposited at temper atures as low as 550-degrees-C and were single-phase perovskite in the as-deposited state. Also, the films were smooth, specular, crack-free , and uniform, and adhered well to the substrates. The stoichiometry o f the films can be easily controlled by varying the individual precurs or temperature and/or the flow rate of the carrier gas. Auger electron spectroscopic (AES) depth profile showed good compositional uniformit y through the thickness of the films. The AES spectra also showed no c arbon contamination in the bulk of the films. As-deposited films were dense and showed uniform and fine grains (almost-equal-to 0.1 mum). Th e optical properties of the films on the sapphire disks showed high re fractive index (n = 2.413) and low extinction coefficient (k = 0.0008) at a wavelength of 632.8 nm. The PZT (82/18) film annealed at 600-deg rees-C showed a spontaneous polarization of 23.3 muC/cm2 and a coerciv e field of 64.5 kV/cm.