Sol-gel processing has proven to be a commercially viable process for the production of certain ferroelectric films, most notable Pb(Sr, Ti)O3 (PZT) and related compounds. The extension of this process to other ferroelectric oxide systems is still in the developmental stages because much is not yet understood about how the specific sol-gel chemistry influences microstructural development. In the PZT system, optimization of the sol-gel chemistry and the resultant microstructure were key developments in obtaining optimal ferroelectric properties. In this talk, the role of analytical TEM in studying microstructural development in sol-gel derived ferroelectric oxide thin films will be discussed. Examples will be drawn from LiNbO3, KNbO3, (Sr, Ba)NbO3 (SBN), and BaTiO3.Mixed alkoxide precursors were used as sols and all films were spin coated onto substrates. Substrate choices ranged from (100) MgO for SBN, BaTiO3 , and KNbO3 and (0001) Al2O3 for LiNbO3 as well as (100) and (111) Si and Pt coated Si. Films were pyrolized after each coating at temperatures from 300-400°C.
Enhancement of the switchable diode effect by the surface hydroxylation of ferroelectric oxide thin films
