Orientation dependence of electrical properties for Bi4−xNdxTi3O12 (x = 0.85) thin film deposited on p-type Si(1 0 0) substrate

Neodymium-substituted Bi4Ti3O12 ((Bi4−xNdx)Ti3O12, x = 0.85, BNdT) thin films have been deposited on p-type Si(1 0 0) substrates by a chemical solution deposition method. By changing the film preparation process, the preferred orientations of the BNdT films exhibit a dramatic differences: randomly oriented or predominantly c-axis-oriented thin films. The well-characterized C-V curves were demonstrated to prove the ferroelectricities of both BNdT thin films prepared by different processes. The frequency-dependent C-V curves of the BNdT thin films show that the high frequency stability from 102 to 107 Hz, which can be adapted for microwave and high-speed memory applications. Dielectric constant and fixed charge density of the randomly orientated and the predominantly c-axis-oriented BNdT thin films were calculated as 340, 410 and 2.6 × 1011 cm−2, 2.9 × 1011 cm−2, respectively. From the leakage current analysis, the dominant current conduction mechanisms of both BNdT thin films on p-type Si(1 0 0) substrates were found to be the Schottky emission with barrier heights of 0.05-0.1 eV at high voltage region.