Carbon nitride films were grown on Si substrates by a microwave plasma chemical vapor deposition method, using mixture of N-2, CH4 and H-2 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 gm. The X-ray photoelectron spectroscopy suggests that nitrogen and carbon in the films are bonded through hybridized sp(2) and spa configurations. The X-ray diffraction pattern indicates that the major part of the films is composed of alpha-, beta-, pseudocubic C3N4 and graphitic C3N4. The Raman peaks match well with the calculated Raman frequencies of alpha- and beta-C3N4, revealing the formation of the alpha- and beta-C3N4 phase.