CHARACTERIZATION OF HYDROGENATED AMORPHOUS SILICON-CARBON FILMS DEPOSITED BY HYBRID-PLASMA CVD

We propose a new deposition process, hybrid-plasma CVD, to overcome the difference in decomposition of source gases. In this new process, SiH4 and CH4 are decomposed individually in a RF plasma and a microwave plasma, respectively, for the deposition of CH4 hydrogenated amorphous silicon-carbon. Efficient decomposition of CH4 by a microwave plasma reduces the excess hydrogenation of carbon atoms. Reactions in the hybrid-plasma CVD are investigated by quadrupole mass spectroscopy. Film structures are investigated by Fourier transform infrared absorption and X-ray photoelectron spectroscopy, and electrical properties are also examined. The films show low hydrogenation of the C atom compared to the films of glow discharge method. Moreover, the films with optical bandgap less than 2.2 eV show photoconductivities in the range of 10(-5) S/cm.