PREPARATION OF PB(ZR0.54TI0.46)O3 THIN-FILMS ON (100)SI USING TEXTURED YBA2CU3O7-LAMBDA AND YTTRIA-STABILIZED ZIRCONIA BUFFER LAYERS BY LASER PHYSICAL VAPOR-DEPOSITION TECHNIQUE

We have fabricated high-quality [00l] textured Pb(Zr0.54Ti0.46)O3 (PZT) thin films on (001)Si by interposing [00l] textured YBa2Cu3O7-delta (YBCO) and yttria-stabilized zirconia (YSZ) buffer layers using pulsed laser deposition (KrF excimer laser, lambda=248 nm, tau=20 ns). The YBCO layer provides a seed for PZT growth and can also act as an electrode for the PZT films, whereas YSZ provides a diffusion barrier as well as a seed for the growth of YBCO films on (001)Si. These heterostructures were characterized using x-ray diffraction, high-resolution transmission electron microscopy, and Rutherford backscattering techniques. The YSZ films were deposited in oxygen ambient (approximately 9 X 10(-4) Torr) at 775-degrees-C on (001)Si substrate having [001] YSZ//[001]Si texture. The YBCO thin films were deposited in situ in oxygen ambient (200 mTorr) at 650-degrees-C. Temperature and oxygen ambient for the PZT deposition were optimized to be 530-degrees=C and 0.4-0.6 Torr, respectively. The laser fluence to deposit this multistructure was 2.5-5 J/cm2. The [00l] textured perovskite PZT films showed a dielectric constant of 800-1000, a saturation polarization of 37.81 muC/cm2, remnant polarization of 24.38 muC/cm2, and a coercive field of 125 kV/cm. The effects of processing parameters on microstructure and ferroelectric properties of PZT films and device implications of these structures are discussed.