The effect of buffer layer on the structural and electrical properties of (BaSr)TiO3 thin films deposited on indium tin oxide-coated glass substrate by using a rf magnetron sputtering method

Abstract

Y2O3 and Si3N4 layers of 50–60 nm thickness were employed as a buffer layer to improve the electrical characteristics between (BaSr)TiO3 thin film and ITO-coated glass substrate. Films were deposited by a rf magnetron sputtering method. In order to investigate the influence of the buffer layer on the structural and electrical properties, XRD, SEM, and SIMS analysis were conducted, and dielectric constant (ε′), dissipation factor (tan δ), voltage-current (V-I), and breakdown fields were measured as a function of (BaSr)TiO3 film thickness. From the results of the SEM and SIMS measurements, it was observed that the buffer layers reduced the influences of the substrate on grown films. Even though the dielectric constant of (BaSr)TiO3 film (440 nm in thickness) was lowered from 238–249 (nonbuffered) to 73–81 (Y2O3 buffered) and 37–43 (Si3N4 buffered) by adopting a buffer layer, the dissipation factor and leakage currents were significantly reduced, which could be explained by the decrease of oxygen diffusion due to the buffer layer. It was also shown that the shift of the breakdown field maximum toward thinner film and the increase of breakdown field occurred by adopting a buffer layer.