Dense yttrium oxide film was prepared on a quartz substrate by the aerosol deposition process at the room temperature. The deposition rate was very high, 60 m/h. Thick film of 10 m was easily achievable on the quartz substrate. Transmission electron microscopy showed that the film was highly dense without voids and was composed of randomly oriented Y2O3 crystallites of sizes smaller than 20 nm. The interface between the film layer and the quartz substrate was homogeneous. The film (2-m thick) had a high transmittance (55-85%) in the wavelength region of 250-800 nm. The mechanical properties of the film were very good. The adhesion force of the interface between the Y2O3 layer and the quartz substrate was over 80 MPa. The Vickers hardness of the film was 7.7 GPa. The film also had an excellent plasma resistance in a gas mixture of CF4/O-2. Outstanding results were noted in eroded depth, surface roughness, nanostructure, and transmittance change after plasma exposure of the film.