Tungsten oxide films containing silicon oxide (SiWOx) as solar control materials were deposited by rf sputtering using Si10W90 and Si50W50 targets. The resistivity and transmittance in the near-infrared region of all the films increased as the O-2/Ar ratio increased. Resistivities from 0.86 Omega cm to 2.27x10(4) Omega cm were obtained depending on the target used and O-2/Ar ratio. The oxidation states of tungsten in the films were estimated by curve fitting XPS spectra. When the films were deposited using a target with a smaller amount of Si (Si10W90), the chemical state of W was similar to that in WO, films. However, lower and novel chemical states of W (W5+, W4+, and W3+) were present when the films were deposited using a target with a larger amount of Si (Si50W50).