The present invention provides a high-performance silicon oxide film as a gate insulation film and a semiconductor device having superior electric characteristics. The silicon oxide film according to the present invention includes CO2 in the film, wherein, when an integrated intensity of a peak is expressed by (peak width at half height)×(peak height) in an infrared absorption spectrum, the integrated intensity of a CO2-attributed peak which appears in the vicinity of a wave number of 2,340 cm−1 is 8E-4 times or more with respect to the integrated intensity of an SiO2-attributed peak which appears in the vicinity of a wave number of 1,060 cm−1.