Silicon and fused-silica targets are used as the starting materials for depositing silicon oxide \left({\text{SiO}}_{\text{2}}\right) films. The {\text{SiO 2}}_{} films are prepared by a dual ion beam sputtering deposition system with a main ion source and an ion-assisted source with different working gases. The films deposited are then examined and compared by using a visible spectrophotometer, a Fourier-transform IR spectrophotometer, an atomic force microscope, and contact angle instruments. A Twyman–Green interferometer is employed to study the film stress by phase-shift interferometry. All the {\text{SiO 2}}_{} films show excellent optical properties with extra-low extinction coefficients (below 2\times {10}^{-5}) and have no water absorption. When the working gas is {\text{O 2}}_{} for the ion-assisted source, the deposited {\text{SiO 2}}_{} films show good properties in terms of stress and roughness and with a good molecular bonding structure order for both targets. However, {\text{SiO 2}}_{} films deposited from the fused-silica target had a larger contact angle, while those deposited from the silicon target had 2.5 times the deposition rate.