Epitaxial Growth of BaTiO3 Optical Thin Films by Pulsed KrF Laser Deposition and in situ Pulsed Laser Annealing

A simple, hybrid process of pulsed KrF laser deposition (PLD) with in situ pulsed laser annealing has been demonstrated. By this method, epitaxial BaTiO3 optical thin (relatively thick) films with a thickness of up to 2 µ m were successfully fabricated on a MgO substrate for the first time. By in situ pulsed KrF excimer laser irradiation of the surface of the growing film, i.e., in situ laser annealing, good smoothness of the film surface and annealing of the film were achieved, allowing the thick film fabrication. The substrate temperature for the fabrication of epitaxial BaTiO3 films was also reduced to 650° C by incorporating the in situ pulsed laser annealing. Refractive indices of the films were measured to be about 2.30–2.12, which is higher than for films without in situ laser annealing.