The physics of sol-gel derived ferroelectric thin film PZT. [PZT (lead zirconate titanate)]

Miscellaneous · Wed Jan 01 00:00:00 EST 1992

OSTI ID:5430828

Melnick, B M

Initial examination of a simple Auger depth profile reveals that thin film, pure lead zirconate titanate (PZT) is a layered structure. Oxygen vacancies at the electrode interfaces create an n-type region in a normally p-type material by contributing electrons into the conduction band. Such measurable effects as the polarization versus applied field and the dielectric constant versus applied field are thickness dependent via a space charge effect on the surface of the material. M.E. Lines has suggested that the decay in switching polarization (fatigue) of barium titanate is linked to buildup of a space charge layer near the surface region. Although no specifics as to the source of the space charge layer are given, it is implied that the space charge layer inhibits switching due to an interaction with the domain nuclei. It is plausible that degradation of the remnant polarization in PZT may be connected with a surface layer. The implication is that thin film ferroelectric materials, such as sol-gel derived PZT, are intrinsically layered structures. This thesis studies ferroelectric PZT synthesized via a solution-gelation technique (sol-gel). Using a reproducible and stable liquid solution, thin films are made by spinning droplets of the metalorganic liquid onto a substrate. The thin layers are dried and annealed to form perovskite phase ferroelectric PZT capacitors. A methodology is presented to test the capacitors unambiguous of artifacts due to the integration process. Capacitance versus voltage (CV), true DC leakage current, switching curve and hysteresis curve data is analyzed. CV analysis indicates a depletion region exists near the surface of the ferroelectric capacitor. The depletion region dominates the switching portion of the CV curves. True DC leakage current measurements indicate that electronic transport within the ferroelectric oxide is space charge limited, displaying a quadratic dependence on the applied voltage according to a modified Childs law.

• Research Organization: Colorado Univ., Boulder, CO (United States)
• OSTI ID: 5430828
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
PZT
ELECTRICAL PROPERTIES
MAGNETIC PROPERTIES
SOL-GEL PROCESS
CAPACITANCE
DIRECT CURRENT
ELECTRIC POTENTIAL
FATIGUE
FERROELECTRIC MATERIALS
HYSTERESIS
INTERFACES
LEAKAGE CURRENT
PEROVSKITE
POLARIZATION
SPACE CHARGE
THIN FILMS
VACANCIES
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CURRENTS
ELECTRIC CURRENTS
FILMS
LEAD COMPOUNDS
MECHANICAL PROPERTIES
MINERALS
OXIDE MINERALS
OXYGEN COMPOUNDS
PEROVSKITES
PHYSICAL PROPERTIES
POINT DEFECTS
TITANATES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
ZIRCONATES
ZIRCONIUM COMPOUNDS
360201* - Ceramics
Cermets
& Refractories- Preparation & Fabrication
360204 - Ceramics
Cermets
& Refractories- Physical Properties