Formation of carbon nitride films by reactive high-density plasma sputtering with excitation of m=0 mode helicon wave

The production of high-density plasmas with excitation of the m=0 mode heli con wave has been studied for the highly reactive sputter synthesis of carb on nitride films in N-2 and N-2+Ar mixtures in the pressure range of simila r to 0.1 Pa. High-density plasmas of 10(12)-10(13) cm(-3) were produced eve n in pure N-2 by using a helical antenna with an azimuthal mode number of m =0. The helicon-wave-excited plasmas have been investigated by wave-magneti c-field measurements and optical emission spectroscopy. The plasma density achieved in 0.26 Pa nitrogen was 4 x 10(12) cm(-3) at a radio frequency (RF ) power of similar to 3 kW and a static magnetic field strength of similar to 1000 Gauss. The wave-magnetic-field measurements confirmed excitation of the m=0 mode helicon wave to propagate in the plasmas at the onset of atta ining the high-density mode. Significant enhancement of line emissions of a tomic nitrogen (N I) and nitrogen ions (N II) was observed in the helicon-w ave-excited plasma, whereas the optical emission spectra in the induction m ode were dominated by those from the molecular bands of nitrogen. Carbon ni tride films have been deposited on a Si(100) substrate by using reactive sp uttering of a cylindrical carbon target with the wave-excited high-density plasmas in N-2 and N-2+Ar mixtures at around 0.1 Pa. Compositional and stru ctural characterization of the CN films was performed by X-ray photoelectro n spectroscopy (XPS) and Rutherford backscattering spectrometry (RBS), show ing that the N/C ratio in the CN films could be controlled up to 1.3. Chemi cal and structural analysis by XPS has been performed. The XPS analysis sho wed the existence of peaks indicating a C-C bond and two C-N bonds where ni trogen is bonded to carbon atoms in sp(2)- and sp(3)-hybridized states. Nan oindentation measurements showed that hardness values as high as similar to 20 GPa were attained at a substrate bias of -200 V. (C) 1999 Elsevier Scie nce S.A. All rights reserved.