New technology for PACVD

Abstract

Plasma-assisted chemical vapour deposition (PACVD) has many advantages for the deposition of thin films. The use of ions for the energetic bombardment of the film during growth is an important technique for producing dense structures. This paper discusses recent progress in the understanding of the effects of energetic bombardment on the stress levels and structure of films produced by plasma deposition processes. Diagnostic equipment, such as the in situ ellipsometer, energy selecting mass spectrometer and residual gas analyser, enables the PACVD process to be closely monitored so that conditions at the growth surface can be accurately controlled. New plasma sources, such as the helicon plasma source, give increased ion fluxes. The cathodic arc source is also an intense source of highly ionized plasma which can be used for PACVD. The deposition of rugate optical structures based on SiO x N y can be carried out using a PACVD process in which the refractive index profile is created by the computer control of gas flows. The helicon plasma source is useful for the deposition of SiO 2 films and has been adapted for use in an ion plating process for the deposition of cubic phase BN. The deposition of amorphous hydrogenated carbon films by PACVD of acetylene in a cathodic arc has been shown to be possible and demonstrates the effect of using a highly ionized plasma for PACVD.