The properties of SiO2 thin films fabricated by dual ion assisted deposition in large coating chamber

Abstract

In this study, single layer SiO₂ thin films were prepared by dual ion assisted deposition (DIAD) on silicon and corning 7980 substrates in large coating chamber. The starting materials were granulated silicon dioxide, and the ion sources were Mark II with gridless end-hall design. Nine SiO₂ single layer samples (labeled S1 to S9) were manufactured by different parameters of ion sources. For the low anode voltage of the ion sources (180V), the refractive index of SiO₂ thin film increased with the rising anode current of the ion source. While for the middle level of anode voltage about 220V, the refractive index decreased with the increasing anode current. But for the high anode voltage (260V), the value of the refractive index decreased first and then increased with the anode current larger. And the SiO₂ thin films were confirmed all amorphous structure by the XRD measurement. The surface roughness and total integrated scattering (TIS) of the film increased as the anode voltage increased. The SEM analysis suggested that the films deposited with high anode voltage showed densely packed columnar microstructures. The XPS analysis indicated that the vast majority of Si on these surfaces is in an oxidized state. The absorption of the film deposited with DIAD increased as the anode voltage increased. All these results are useful to investigate the large-area coating processes.