Impact of microstructure on the electrical properties of zirconium titanate thin films in MOS configuration

摘要

Zirconium titanate thin films were deposited on p - type Si substrate by pulsed excimer laser ablation technique. The thin films were highly oriented along (020) and polycyrstalline depending on the deposition parameters. A correlation of the microstructure with the electrical properties has been studied in detail. C -V, G -V and DC leakage current studies were done on both types of the films. The higher dielectric constant and higher leakage current were observed on the highly oriented thin films than the polycrystalline thin films. The C -V and G -V measurements were carried at higher frequency ranging from 1kHz to 100 kHz in elevated temperatures and the activation energy calculated from arrhenius plot were approximately half the silicon band gap. This suggests that generation recombination mechanism is taking place in the depletion region of Si substrate through bulk traps. The interface states were calculated using high frequency method and it were higher for the polycrystalline than highly oriented thin films. The electronic conduction mechanism is analysed on both the types of films in detail, applying different kinds of mechanism like poolefrenkel, schottky and Space charge limited conduction