FERROELECTRICITY AND ELECTRIC CONDUCTION CHARACTERISTICS OF SR-MODIFIED LEAD-ZIRCONATE-TITANATE THIN-FILM CAPACITORS

Ferroelectric (Pb0.9Sr0.1)(Zr0.53Ti0.47)O-3 (PSZT) thin film capacitor s were prepared on Si substrates with a platinum-electrode coated on t he underside by a sol-gel method. X-ray diffraction patterns showed th at PSZT thin films were polycrystalline and the peaks of perovskite st ructure appeared uniquely in films annealed above 650 degrees C. Ferro electricity and electric conduction characteristics were observed by m easuring the frequency dependent dielectric constant (epsilon'-f), the capacitance versus voltage (C-V), the ferroelectric hysteresis (D-E) loops, and the leakage current density versus field (J-E). The remanen t polarization and the coercive field using a sinusoidal voltage of 1 kHz and 10 V were approximately 21 mu C/cm(2) and 67 kV/cm, respective ly. The ohmic conduction and space-charge-limited current conduction w ere the dominant charge transport mechanisms in sol-gel deposited PSZT films. The resistivity of PSZT films in ohmic conduction region was 4 x 10(8) Omega cm and the density of traps was about 6.5 x 10(19) cm(- 3). The drift mobility at room temperature was about 86 cm(2)/Vs for a 240-nm-thick film and 42 cm(2)/Vs for a 400-nm-thick him.