Synthesis of boron nitride (BN) films are attempted by plasma-assisted chemical vapor deposition using BCl3 and N-2 as source gases. BN films are characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared absorption (FTIR) measurements. Capacitance-voltage (C-V) characteristics are measured for Au/BN/p-Si samples. The dielectric constant is estimated from the capacitance in the accumulation region and the film thickness. A dielectric constant as low as 2.2 is achieved for the BN film. It is found that incorporation of carbon atoms into BN films is effective in reducing the dielectric constant. (C) 2001 Elsevier Science B.V. All rights reserved.