Rapid deposition of (K,Na)NbO₃thick films using microwave-assisted hydrothermal technique

Rapid processing for hydrothermal deposition of (K,Na)NbO3 (KNN) thick films was proposed with the assistance of microwave (MW) heating, for short-time fabrication of ferroelectric/piezoelectric films with thicknesses of several micrometers within 1 h. MW irradiation raised the temperature of water medium up to 240 ?C within 10 min, whereas conventional heating using hot-air convection required more than 2 h. Epitaxial KNN films were successfully deposited on single-crystal substrates of (100)SrTiO3:Nb and (100)SrRuO3//(100)SrTiO3 at reaction temperature of 180 ?C-240 ?C within 1 h; especially, the films with thicknesses over 10 μm could be obtained on at 220 ?C for 40 min. The resulting film exhibited domain structure and dielectric/ferroelectric properties comparable with the KNN films derived from conventional hydrothermal deposition.