Substrate temperature dependent morphology and resistivity of pulsed laser deposited iridium oxide thin films

Abstract

Iridium oxide (IrO 2) thin films were deposited on Si (100) substrates by means of pulsed laser deposition technique at various substrate (deposition) temperatures ranging from 250 to 500 °C. Effects of substrate temperature on the crystalline nature, morphology and electrical properties of the deposited films were analyzed by using X-ray diffraction, Raman spectroscopy, Scanning electron microscopy and four-point probe method. It was found that the above properties were strongly dependent on the substrate temperature. The as-deposited films at all substrate temperatures were polycrystalline tetragonal IrO 2 and the preferential growth orientation changed with the substrate temperature. IrO 2 films exhibited fairly homogeneous thickness and good adhesion with the substrate, the average feature size increases with the substrate temperature. The room-temperature resistivity of IrO 2 films decreased with the increase of substrate temperature and the minimum resistivity of (42 ± 6) μΩ cm was obtained at 500 °C. The resistivity of IrO 2 films correlated well with the corresponding film morphology changes.