BNx-SiNy composite films were deposited by a multisource plasma chemical vapor deposition (PCVD). Two plasma generators, A and B, were implemented. BF3 and NH3 gases introduced to plasma generator A were separately decomposed by two rf electrodes, respectively. SiH4 and NH3 gases were also separately decomposed in the plasma generator B. Widely spread sheet-like plasma generated by a dc arc plasma gun above the substrate and under a magnetic field also excited the gas in front of the substrate. By this CVD system, the composition of the BNx-SiNy films can be controlled, and the BNx-SiNy films with several atomic percent of silicon are found to have higher hardness and higher electrical resistivity than BNx film.