MICROSTRUCTURE PROCESS RELATIONS IN SOL-GEL-PREPARED KNBO3 THIN-FILMS ON (100) MGO

Epitaxial (110) orthorhombic KNbO3 thin films were prepared using alkoxide solutions. Single-phase films were produced with stoichiometric sols while slight variations in stoichiometry (52/48 Nb/K or 48/52 Nb/K) created residual second phases. Nucleation and growth of KNbO3 as a function of process conditions were monitored by observing the KNbO3 rosettes produced from niobium-rich solutions. Methanolic solutions produced films with the highest rosette density and the highest amount of KNbO3. Hydrolysis of the sol aided the crystallization of the KNbO3 phase but also promoted the formation of second phases. Hydrolysis at 0-degrees-C reduced second-phase formation.