Pure and fluorine-doped silica glass were fabricated by plasma chemical vapour deposition (PCVD) and characterized using Raman and infrared spectrum. The change in Raman in-tensity of 945 cm-1 peak, relating to ≡Si-F stretching vibration, agrees with the change of F content. Compared with measured wavenumber in IR spectrum, the calculated absorption wavelength confirms the incorporation form of F into the glass, the detail of which is a tetrahedron with a Si atom in the center coupled with one F atom and three network O atoms. Such structure identification may be useful for explaining some properties of F-doping silica glass.