Barium strontium titanate (BST) thin films were grown directly on Si substrates by an in situ ultraviolet (UV)-assisted pulsed laser deposition (UVPLD) technique. With respect to films grown by conventional (i.e. without UV illumination) pulsed laser deposition (PLD), the UVPLD grown films exhibited improved structural and electrical properties. The dielectric constant of a 40-nm thick film deposited at 650 °C was determined to be 281, the leakage current density was approximately 4×10-8 A/cm2 at 100 kV/cm, and the density of interface states at the flat-band voltage was found to be approximately 5.6×1011 eV-1cm-2. X-ray photoelectron spectroscopy investigations found that the surface of the grown films exhibited an additional Ba-containing phase, besides the usual BST perovskite phase, which was likely caused by stress and/or oxygen vacancies. The amount of this new phase was always smaller and very superficial for UVPLD grown films, which can explain their better overall properties.
|Materials Research Society Symposium - Proceedings
|Published - 2000
|Laser-Solid Interactions for Materials Processing - San Francisco, CA, United States
Duration: 25 Apr 2000 → 27 Apr 2000