Structural and mechanical properties of dc and pulsed dc reactive magnetron sputtered V₂O₅films

Abstract

Vanadium pentoxide (V2O5) thin films were deposited onto Si (1 0 0) substrates using dc and pulsed dc reactive magnetron sputtering at 26, 100 and 300 °C to investigate the influence of substrate temperature and sputtering mode on their structural and mechanical properties. X-ray diffraction, Raman spectroscopy and scanning electron microscopy revealed that the structural characteristics and the surface morphology of the V2O5 films depend on both sputtering mode and deposition temperature. With increasing deposition temperature, the films deposited by dc sputtering show a transition from amorphous at room temperature to polycrystalline growth with a preferred (2 0 0) orientation. This leads to an increase in hardness and elastic modulus of the films from 3.2 ± 0.1 GPa and 79.4 ± 3.2 GPa at 26 °C to 4.8 ± 0.6 GPa and 129.2 ± 6.4 GPa at 300 °C, respectively. In contrast, the films deposited by pulsed dc sputtering exhibit a polycrystalline α-V2O5 structure over the whole temperature range. The hardness of these films decreases with increasing deposition temperature while Young's modulus is almost unaffected.