Low temperature synthesis and properties of lithium niobate thin films

Thin films of lithium niobate were deposited on silicon (100) by a sol-gel technique and were annealed in oxygen at 400 °C. The annealed films were characterized by x-ray diffraction and transmission electron microscopy which showed crystallization to LiNbO3, a preferred orientation of the films, and an average grain size of about 0.5 μm. Electrical characterization of the films in the metal-ferroelectric-semiconductor configuration showed evidence for ferroelectricity via the hysteresis loop. The dielectric constant and dissipation factor were measured at frequencies from 10 Hz to 10 MHz with a dielectric constant of 35 and dissipation factor of 0.004 at 100 kHz. The current-voltage characteristics of the films exhibited asymmetric behavior, indicating a possible Schottky barrier and showed a leakage current density of 1.1×10−4 A/cm2 at 3 V.