Processing, crystallization behaviour and dielectric properties of metallorganic deposited Nb doped PZT thin films on highly textured 111-Pt

Nb5+ doped PZT thin films of a nominal stoichiometry of Pb-1.1(Zr-0.47, Ti- 0.47, Nb-0.05)O-3 have been processed via metallorganic deposition on (111) -Pt/TiO2/SiO2/Si. The crystallization textures and crystallization kinetics have been investigated in the temperature range from 550 to 700 degreesC, starting from a common pre-firing condition at 500 degreesC. The dielectric and ferroelectric properties are also reported. It is shown that crystalli zation proceeds from the nanocrystalline pyrochlore phase with the formatio n of specific textures. From 550 to 650 degreesC (100)/(111) and (111)/100 textures predominate whereas at 700 degreesC highly textured (100) films we re obtained. The crystallization kinetics follow a parabolic law of the Avr ami-type with an exponent of 1.5 at 550 degreesC and approx. 0.5 in the tem perature range from 600 to 650 degreesC. This is interpreted in terms of di fferent growth mechanisms. The ferroelectric and dielectric properties are shown to depend on firing conditions and micro structure. Dielectric consta nts in the range from 800 to 2200 are obtained. The results are discussed i n comparison to non-doped PZT. (C) 2001 Elsevier Science B.V. All rights re served.