STRUCTURAL AND OPTOELECTRONIC PROPERTIES OF CARBON-RICH HYDROGENATED AMORPHOUS SILICON-CARBON FILMS

In this paper we present a study on a-SiC:H films with energy gap in t he range 2.2-3.5 eV grown by plasma-enhanced CVD from CH4 + siH(4) mix tures, with and without H-2 dilution. The compositional, structural an d optoelectronic properties of the films were characterized using Ruth erford backscattering and elastic recoil detection analysis, IR absorp tion spectroscopy, transmittance-reflectance and electron spin resonan ce measurements. As H-2 is added to the plasma, an evolution of IR pro perties and changes in the atomic composition and in the density of th e films were observed. The structure of the films evolves towards a mo re compact network, with increased incorporation of carbon atoms and p romotion of CH2 bonding. This is accompanied by an increase in spin de nsities up to 10(19) cm(-3).