Processing and properties of sol-gel derived lithium niobate thin-layers

Sol-gel processing was investigated as a method of deposition for lithium niobate thin layers on a variety of substrates, including silicon, platinum, and sapphire. The influence of solution chemistry and thermal processing conditions on microstructure developed was studied especially for the integration of LiNbO₃ on Si. An ethanol-based system gave dense layers with grain sizes ranging between 0.1 and 0.2 μm. Methoxyethanol-based systems also produced dense layers, but the grain sizes were somewhat larger, approaching 0.5 μm. Electrical properties are reported for LiNbO₃ on Pt. The layers had preferred orientation, with values of dielectric constant and loss tangent of 22 and 0.005, respectively, at 25°C and 1 MHz