Preparation of ferroelectric lead zirconate titanate thin films using high molarity precursor sols

Ferroelectric PZT thin films were successfully prepared using an organometallic deposition procedure. The precursor sol with composition near the morphotropic phase boundary (Zr/Ti = 53/47) consisted of lead acetate trihydrate, zirconium and titanium n- propoxide stabilized with acetylacetone and 1,3 propanediol as solvent. No protecting atmosphere was necessary and the sol was stable for more than 100d. Films on Si-wafers, covered with Pt as electrode material were produced by spin coating. A fast heat treatment to remove organic moieties and to promote the densification was found to be suitable to improve the quality of the films. The presence of the perovskite phase was detected by X-ray diffraction after a heat treatment at temperatures as low as 500 degree. Due to the high molarity of the precursor solution (bigger 2M) polycrystalline, dense, smooth and crackfree films with a thickness up to 1 mym could be produced with a single coating step. The films had good dielectric properti es and well developed ferroelectric hysteresis loops. A typical 0,7 mym thick film of the composition Pb1Zro,53Ti0.4703 annealed at 700 degree exhibited remanent polarization of 14myC/square cm, a coercive force of 7kV/mm, an eps r of 950(5kHz, 25 degree) and a resistance higher than 10 MOhm.