STUDY OF BA1-XSRXTIO3 THIN-FILMS FABRICATED BY SOL-GEL METHOD

Thin Films of Barium Strontium Titanate (BST) - Ba0.65Sr0.35TiO3 and B a0.5Sr0.5TiO3 - were deposited on the Si substrate with 200 approximat ely 300nm thickness by sol-gel method. The precursor solution of BST w as prepared by mixing the 0.2 M precursor solutions of BaTiO3 and SrTi O3 with proper molar ratio. The x-ray diffraction (XRD) patterns showe d characteristic peaks with very weak intensities indicating that the BST film had polycrystalline structure. XRD results also imply that th e grain size may be very small. The grain size and the surface morphol ogy of the films were investigated by atomic forced microscope (AFM). Also the crystallinity of the films would be reported for various cond itions of deposition and heat treatment. The dielectric constants of t he films with MIS (metal - insulator - semiconductor) structure were f ound to be in the range of 40 approximately 100 which is smaller than that of the single crystal. We also measured the leakage currents of t he films up to 650 kV/cm where the breakdown occurred.