Structural, Morphological and Electrical Studies on Barium Strontium Titanate Thin Films Prepared by Sol-Gel Technique

Abstract

The crystal structure, surface morphology, compositional homogeneity and electrical properties of barium strontium titanate (BST) thin films are investigated. The films were deposited on bare silicon and platinum coated silicon substrates by spin coating process. The precursor solution with Ba/Sr ratio 70/30 was prepared by sol-gel synthesis using metal alkoxides. The crystalline nature and morphology of the films are found to be strongly influenced by the heating cycle adopted to form the Ba 0.7 Sr 0.3 TiO 3 layer. The elemental composition analysis on the surface and in-depth confirms the stoichiometry of the films. The dielectric constant at 100 kHz and dissipation factor at room temperature is found to be 120 and 0.0236 for the films with 400 nm thickness annealed at 700°C for 2 hrs. The leakage current density of the film is found to be 4x10 -8 A/cm 2 from I-V measurements.