Nanocrystalline silicon carbonitride thin films prepared by plasma beam-assisted deposition

Nanocrystalline silicon carbonitride thin films were prepared by reactive co-sputtering of graphite and silicon on Si(111) substrates. Asymmetrical RF biasing of the plasma served to sputter the target at high energy ( > 2 keV) and to simultaneously bombard the growing film at moderate energy (up to 180 eV). The films grown with pure nitrogen gas are exclusively amorphous. Nanocrystallites of 400-490 nm in size were observed by atomic force microscopy in films deposited with a mixture of N-2 + Ar. Film,, of greater carbon content were polymerized. displaying a lamellar morphology, A maximum Vickers hardness of 14.1 GPa Was Measured in crystalline specimens. The films were further characterized by X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy and X-ray diffraction. Quantification of the XPS data proceeded with relative sensitivity factors established on stoichiometric 4H-SiC and alpha -Si3N4 standards (S-S1/S-C( = 1: 1,37, S-S1/S-S = 1: 1.16). The results measured are briefly discussed with reference to the deposition parameters. (C) 2001 Elsevier Science B.V. All rights reserved.