Synthesis and Electrical Characterization of Thin Films of PT and PZT Made from a Diol‐Based Sol‐Gel Route

Abstract

Lead titanate (PT) sols were prepared using propanediol, butanediol, or pentanediol solutions of lead acetate trihydrate and titanium diisopropoxide bis(acetylacetonate). Precursor sols for PbZr 0.53 Ti 0.47 O 3 (PZT) films were prepared from propanediol solutions, with zirconium tetrapropoxide being used as the zirconium source. Films were formed by spin‐coating the sols onto silicon and platinized silicon substrates; the resulting gel layers were converted to ceramic films by adopting a two‐stage heating schedule with final firing temperatures of 600–700°C. Information on film crystallization, microstructure development, and electrical properties is presented for both compositions. The limiting thickness of surface‐smooth crack‐free single‐layer films was ∼1 μm. The PT films exhibited a “linear” polarization‐electric field ( P‐E ) response, while the PZT films gave rise to characteristic ferroelectric P‐E hysteresis loops. A 0.5 μm thick single‐layer PZT film exhibited remanent polarization (P r ) values of ∼34 μC·Cm −2 , with a coercive field ( E c ) of ∼45 kV·Cm −2 ; the relative permittivity (ɛ r ) and the dissipation factor ( D ) were ∼1250 and 0.07. For a 1 μm single‐layer PZT film, the respective values were P r ∼19 μC∼Cm −2 , E c ∼40 kV∼Cm −2 , ɛ r ∼750, and D = 0.03.