Influence of heat treatment on LiNbO₃ thin films prepared on Si(111) by the polymeric precursor method

The effects of heat-treatment temperature on LiNbO₃ thin films prepared by the polymeric precursor method were investigated. The precursor solution was deposited on Si(111) substrates by dip coating. X-ray diffraction and thermal analyses revealed that the crystallization process occurred at a low temperature (420 °C) and led to films with no preferential orientation. High-temperature treatments promoted formation of the LiNb₃O₈ phase. Scanning electron microscopy, coupled with energy dispersive spectroscopy analyses, showed that the treatment temperature also affected the film microstructure. The surface texture—homogeneous, smooth, and pore-free at low temperature—turned into an “islandlike” microstructure for high-temperature treatments.