Precipitation kinetics of LiNbO 3 and LiNb 3O 8 crystalline phases in thermally annealed amorphous LiNbO 3 thin films

Abstract

The pyrochlore (LiNb 3O 8) phase in lithium niobate crystal does not contribute to ferroelectric or electrooptic properties. We investigated a way to suppress the precipitation of this phase that was formed by thermally annealing amorphous LiNbO 3 films. The volume fraction of LiNb 3O 8 with respect to LiNbO 3 becomes higher during longer annealing periods and at higher annealing temperatures because of the evaporation of Li 2O units from the surface. Annealing in an O 2 atmosphere promotes the formation of the pyrochlore phase more than in a vacuum. We propose rapid thermal annealing of oxygen-rich LiNbO 3 film in a vacuum to provide the best solution to obtaining transparent, single LiNbO 3 phase film. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.