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. © 2001 American Vacuum Society.