OPTICAL-EMISSION ANALYSIS OF A SI(CH3)(4)-ARGON RADIO-FREQUENCY PLASMA FOR SIC FILMS DEPOSITION

RF glow discharges from tetramethylsilane diluted in an argon flow hav e been investigated ina cold wall R.F. (2MHz) P.E.C.V.D. reactor. This reactor is used for fast deposition of adherent amorphous silicon car bide films (with Si/C approximate to 1.2) on steel. Optical emission f rom the plasma was sampled using a high resolution double monochromato r (2m focal length, 1800 grooves/mm) coupled with a multichannel CCD d etector. Only the lines corresponding to neutral or ionised Argon (Ar, Ar+), the broadened hydrogen Balmer (H alpha et H beta) and silicon i onised lines (Si+) were clearly pointed out perpendicularly or paralle l to the discharge axis. The different broadenings observed were due t o Doppler effects and connected with the movement of radical species. With TMS, the fine structure of the hydrogen line is deconvoluted in t hree gaussian like components, one of which denote high energy atoms c oming from a TMS derived species. Previous mechanisms for hot atom pro duction do explain our results, but the various experimental brodening s could be ascribed to gradients in the cathode sheath adjacent to the substrate, and the hot atoms could be produced by electron impact on intermediate fragments, one bearing silicon, the other bearing carbon.