Surface and nanomechanical properties of Si:C:H films prepared by RF plasma beam CVD

Abstract

Si-, SiO x- and SiN x-containing a-C:H films (denoted as DLCSi, DLCSiO and DLCSiN) were deposited respectively from tetramethylsilane, hexamethyldisiloxane and hexamethyldisilazane precursors onto silicon wafer and aluminium substrates, using electron cyclotron wave resonance (ECWR) plasma beam CVD. Surface chemical analysis was performed by X-ray photoelectron spectroscopy and X-ray induced Auger electron spectroscopy. Nanomechanical properties like hardness and reduced modulus were determined by the nanoindentation method. For the DLCSi layers the C/Si ratio increased with the increase of the self-bias. Nanohardness and reduced modulus had a strong tendency to increase with increasing C/Si. The modified Auger parameter for silicon (Si α) and the bulk plasmon loss energy of the C 1s peak ( E p) also increased with C/Si. For the whole set of Si-containing a-C:H film samples a correlation has been established between Si α and E p.