Effects of growth temperature on structure and electrical properties of dielectric (Ba,Sr)TiO3 capacitors with transparent conducting oxide electrodes

200 nm-thick BST thin films were grown on Zr-doped In2O3/SrTiO3 (1 0 0) substrates at 550–750 °C. X-ray diffraction results show that the as-deposited BST films were polycrystalline with random crystallographic orientations. X-ray diffraction patterns reveal that the BST film grown at 650 °C had the best crystalline quality of all the deposition temperatures. Atomic force microscopy and secondary ion mass spectrometry showed that the surface and interface structures of the BST films became rough as the growth temperature increased. The BST film grown at 650 °C showed the best electrical properties, with a dielectric constant of 420 at 1 MHz, dielectric tunability of 32.1%, dielectric loss of 0.015 at 300 kV/cm, and a mean optical transmittance in visible wavelength of 71.3%.

► High growth temperature results in more oxygen vacancies or defects in the Ba0.6Sr0.4TiO3 thin film.
► Serious interdiffusion between the Ba0.6Sr0.4TiO3 and Zr-doped In2O3 thin films might occur at a growth temperature of 750 °C.
► The BST film grown at 650 °C on the Zr-doped In2O3 electrode showed good dielectric properties and a mean optical transmittance above 70% in the visible wavelength regions.