Surface morphology of sputtered Ta₂O₅ thin films on Si substrates from X-ray reflectivity at a fixed angle

The temporal variation of the surface morphology of Ta₂O₅ films on Si substrates has been measured using X-ray reflectivity at a fixed angle during radio-frequency magnetron sputtering. During an early stage of growth of polycrystalline Ta₂O₅, the variation of surface roughness revealed a morphology of island nucleation and island coalescence.