Crystallization behaviour and electrical properties of wet-chemically deposited lead titanate zirconate thin films

A new one step deposition process for smooth and crackfree films with a thickness equal or bigger than 1 mym has been developed in the system Pb(Zr1-x Tix)O3 (PZT). Starting from lead acetate trihydrate, zirconium- and titanium-n-propoxide, high molarity (bigger than 2M) coating sols have been prepared that can handled at air. The sols are stable for more than 170 days. Films with compositions near the morphotropic phase boundary (x=47) and different lead contents were deposited by a spin-off method. The wet films could be dried and pyrolyzed with a fast heat treatment without cracking. The crystallization behaviour of the films was studied by normal and high temperature X-ray diffraction techniques. The crystallization of films deposited on Pt-coated Si- wafers and Al2O3-substrates in the desired perovskite structure started at comparatively low temperatures (ca. 530 centigrade) and proceeded very quickly at temperatures above 650 centigrade. A slight molar excess of lead and a fast h eating rate were found to produce the best electrical properties. The films showed device-worthy dielectric and ferroelectric properties with typical values for the Pr, Ec and epsr of 14 myC/cm2, 7kV/mm and 950 respectively.