Diffusion properties of point defects in barium strontium titanate thin films.

The relationship between the diffusion behavior of hydrogen and the electrical properties of (Ba, Sr)TiO3 (BST) thin-film capacitors was investigated using thermal desorption spectroscopy and secondary ion mass spectroscopy analyses. It has been clearly shown that the frequency dependence of the complex impedance profile of the BST thin-film capacitors could be successfully represented by two parallel resistor-capacitor (RC) electrical equivalent networks in series correlated with the distribution of the hydrogen, namely, the Pt/BST interface region with the influence of hydrogen and the BST bulk region without the influence of hydrogen. However, the I-V properties of the BST thin-film capacitors could be determined almost from the hydrogen atoms existing at the Pt/BST interface.