Preparation and properties of IrO₂ thin films grown by pulsed laser deposition technique

Abstract

Highly conductive IrO₂ thin films were prepared on Si (100) substrates by means of pulsed laser deposition technique from an iridium metal target in an oxygen ambient atmosphere. Emphasis was put on the effect of oxygen pressure and substrate temperature on the structure, morphology and resistivity of IrO₂ films. It was found that the above properties were strongly dependent on the oxygen pressure and substrate temperature. At 20 Pa oxygen ambient pressure, pure polycrystalline IrO₂ thin films were obtained at substrate temperature in the 300–500 °C range with the preferential growth orientation of IrO₂ films changed with the substrate temperature. IrO₂ films exhibited a uniform and densely packed granular morphology with an average feature size increasing with the substrate temperature. The room-temperature resistivity variations of IrO₂ films correlated well with the corresponding film morphology changes. IrO₂ films with the minimum resistivity of (42±6) μΩ·cm was obtained at 500 °C.

Keywords

iridium oxide thin films / pulsed laser deposition / resistivity / microstructure

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