BCN films on silicon substrates were deposited with two different PECVD techniques. A microwave plasma with RF-bias enhancement (MW-PECVD) and a direct current glow discharge plasma system (GD-PECVD) was used with N-trimethylborazine (TMB) and triethylamine borane (TEAB) as precursors and with benzene as an additional carbon source. Argon and nitrogen were used as plasma gases. Substrate temperature, substrate bias and gas composition were varied. ERDA (elastic recoil detection analysis) measurements yield information on the layer composition regarding the concentrations of the elements boron, carbon, nitrogen and hydrogen. Depth profiles are also available. The hydrogen content in the produced BCN layers strongly depends on the substrate temperature and increases up to 35 at.%. Depth profiles show a homogeneous distribution of the elements B, C, N and H over the entire layer thickness. Further, the layers were examined regarding their structure (FTIR spectroscopy) and their mechanical properties (nanoindentation measurements). (c) 2005 Elsevier B.V. All rights reserved.