Boron carbon nitride films are synthesized in a horizontal quartz reactor by plasma-assisted chemical vapor deposition. Boron trichloride (BCl_3), nitrogen (N_2) and methane (CH_4) are used as source gases. Plasma of N_2 and CH_4 is produced by supplying RF power to the turn coil BCI3 is transported near the substrate by H_2 gas. The substrate temperature is kept at 730 deg C. The BCN film with B, C, N and O composition ratios of 43 percent, 30 percent, 24 percent and 3 percent is characterized. Thermal desorption spectroscopy (TDS) measurement is carried out for the BCN film treated with D_2O. Desorption of D_2O from the BCN film occurs at 230 deg C, 420 deg C and 730 deg C. Desorption of D_2 also occurs at 750 deg C. The impedance of the as-deposited and water-treated BCN films is investigated by ac measurement. The impedance of the as-deposited BCN film depends on the -0.9 power law of the frequency. On the other hand, the impedance of the water-treated BCN film decreases in the frequency range lower than 10~4 Hz. This is because another electrical conduction other than the quantum-mechanical tunneling hopping conduction becomes dominant due to water incorporation into the BCN film.
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