B-C-N films were synthesized by using the chemical vapor deposition in which the starting material dimethylamineborane was transported onto a substrate with nitrogen gas, and analyzed with secondary electron microscopy, Raman scattering, infrared spectroscopy, x-ray photoelectron spectroscopy, transmission electron microscopy, electron diffraction, x-ray diffraction, and ultraviolet-visible-rays absorption spectroscopy. Effects of substrate temperature and deposition pressure on the solid-solutions of B-C-N films were investigated by changing substrate temperature between 700 and 1000 degreesC under deposition pressure between 100 and 760 Torr. It was found that a mixture of microcrystal glassy carbon and turbostratic-BN both with an apparent crystal size of about 10 Angstrom was deposited under the atmospheric pressure at 1000 degreesC. In deposition where the pressure was reduced from the atmospheric pressure to 600 Torr, BN gradually lost the stoichiometric compositions to form a mixed structure of BNx (x < 1) and glassy carbon. In deposition where the pressure was lowered than 600 Torr, BNxCy : H (x,y < 1) of which dangling bonds wereterminated with hydrogen was produced as a result of further decrease of the BNx nitriding rate and then substitution of carbon for nitrogen. This BNxCy : H (x,y < 1) showed character close to amorphous material and the composition ratio varied continuously for the deposition pressure change.