Investigation of temperature dependent current-voltage characteristics of Ba0.5Sr0.5TiO3 thin films

Abstract

The Ba0.5Sr0.5TiO3 (BST) thin films were deposited via radio frequency cathode sputtering on sapphire (α-Al2O3) and gadolinium gallium garnet (GGG) substrates. The effect of substrate material on the leakage current and mechanism of conductivity in BST stacks has been studied by tempera-ture dependent (300…400 K) current-voltage characteristics. Lower leakage currents of BST/α-Al2O3 thin films were achieved compared with that of BST/GGG thin films, especially in the high field re-gion. The conduction mechanism of the deposited films is found to be of Schottky emission type for a wide range of applied fields on both substrates. Schottky barrier height, effective Richardson con-stant, effective mass of conduction electrons in dielectric, and dynamic dielectric constant within the bounds of thermionic emission theory were found.

Keywords

• transport phenomenon
• dielectric
• conduction mechanisms
• schottky emission