Carbon nitride films were grown on Si substrates by a microwave plasma chemical vapor deposition method, using mixture of N2, CH4 and H2 as precursor. Scanning electron microscopy shows that the films consisted of a large number of hexagonal crystallites. The dimension of the largest crystallite is about 3 µm. The X-ray photoelectron spectroscopy suggests that nitrogen and carbon in the films are bonded through hybridized sp2 and sp3 configurations. The X-ray diffraction pattern indicates that the major part of the films is composed of α-, β-, pseudocubic C3N4 and graphitic C3N4. The Raman peaks match well with the calculated Raman frequencies of α- and β-C3N4, revealing the formation of the α- and β-C3N4 phase.