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

摘要

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℃. 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℃. The resistivity of IrO_2 films correlated well with the corresponding film morphology changes.