Amorphous silicon carbon nitride (a-SiCN:H) films were synthesized using vapor transport-chemical vapor deposition technique. Poly(dimethylsilane) was used as a single source for both Si and C. NH3 gas diluted in Ar is used as a source for nitrogen. The composition and bonding states are uniquely characterized with respect to NH3/Ar ratio by Fourier transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS). Spectral deconvolution is used to extract the individual components of the FTIR and XPS spectra. For instance, the FTIR spectra show a remarkable drop in the intensity of SiC vibration accompanied by the formation of further bonds including SiN, CN, CN, CN, and NH with increasing NH3/Ar ratio. Moreover, the XPS spectra show the existence of different chemical bonds in the a-SiCN:H films such as SiC, SiN, CN, CN, and CC. Both FTIR and XPS data demonstrate that the chemical bonding in the amorphous matrix is more complicated than a collection of single SiC SiN, or SiH bonds.