ELECTRICAL PROPERTIES OF HETEROPHASE PZT THIN FILMS WITH EXCESS LEAD OXIDE

ABSTRACT

Inclusions of lead oxide in ex-situ grown PZT thin films are known to give rise to a phenomenon of self-polarization. It is shown that dependence of self-polarization on thickness in the films deposited on glass ceramic/Pt substrate differ substantionally from that for ones deposited on Si/SiO₂/Pt substrate. Different behaviour of curves is discussed in terms of mechanical comprehensive or tensile stresses acting upon the films by the substrate. Two types of mesoscopic scale dielectric constant nonuniformity over the entire surface of the film samples are studied. One of them deals with a local broken texture of grains in self-polarized films and another one is observed in the films annealed at temperature range of phase transformation from perovskite polycrystalline disordered phase to perovskite <110>-textured phase. The role of lead oxide inclusions in the films is discussed.

Keywords:

• PZT thin films
• lead oxide inclusions
• self-polarization
• dielectric permittivity
• structural nonuniformity

ACKNOWLEDGMENTS

This study was supported by the Russian Foundation for Basic Research (project no. 08-02-01352) and ISTC Project 3743.