Accession Number : ADP006647

Title :   Process Dependent Electrical Characteristics and Equivalent Circuit Model of SOL-GEL Based PZT Capacitors,

Corporate Author : COLORADO UNIV AT COLORADO SPRINGS

Personal Author(s) : Mihara, Takashi ; Watanabe, Hitoshi ; Yoshimori, Hiroyuki ; Paz De Araujo, C. A.

Report Date : 05 APR 1991

Pagination or Media Count : 23

Abstract : Studies of electrical properties and an equivalent circuit model is developed for ferroelectric PZT(Ti = 60%) thin film capacitors made by sol-gel spin coating with Pt electrodes. The equivalent circuit consists of two major parts: serial space charge capacitors demonstrating surface effects and parallel elements modeling the inner polycrystalline ferroelectric regions. This model is based on device physics which can demonstrate both the measured capacitance voltage characteristics and hysteresis curves. From the model fit to the data, an estimate of the space charge concentration at the surface and inner grain boundary region of 5x10(20) cm(-3) and 1x10(18) cm(-3) respectively is made. Further electrical characterizations such as pulse switching and polarization degradation (fatigue) have also been studied. Using the equivalent circuit, other characteristics such as the switching time can be studied showing its dependence on applied voltage and capacitor area. The applied voltage dependence of fatigue is shown via an empirical equation where the degradation rate is electric field activated.

Descriptors :   *EQUIVALENT CIRCUITS, *THIN FILM CAPACITORS, *FERROELECTRIC MATERIALS, BOUNDARIES, CAPACITANCE, COATINGS, DEGRADATION, ELECTRIC FIELDS, ELECTRICAL PROPERTIES, ELECTRODES, EQUATIONS, ESTIMATES, FATIGUE, GELS, GRAIN BOUNDARIES, HYSTERESIS, MODELS, POLARIZATION, POLYCRYSTALLINE, PULSES, RATES, SPACE CHARGE, SURFACES, VOLTAGE, LEAD TITANATES, ZIRCONATES, ELECTRIC SWITCHES.

Subject Categories : Electricity and Magnetism
      Electrical and Electronic Equipment
      Ceramics, Refractories and Glass

Distribution Statement : APPROVED FOR PUBLIC RELEASE