Influence of selected process parameters on the deposition of polymer-like amorphous hydrogenated carbon films in glow discharges

Abstract

In the present work the deposition conditions for the production of amorphous hydrogenated carbon films on aluminium substrates were investigated in a benzene and a chlorobenzene discharge. With experimental design and evaluation by the analysis of variance, in the fixed experimental range the power, plasma treatment time, evaporator temperature and the type of plasma discharge substance have been shown to exercise a significant influence on the deposition rate as response. By choosing an appropriate selection of these significant parameters, an increase in the deposition rate of more than the seventeenfold has been observed. The characterization by means of electron energy loss spectroscopy in connection with IR and Raman spectroscopic data has revealed a polymer-like composition of the deposited films; however, in films produced in a chlorobenzene discharge the polymer content was higher than in those from benzene. The small differences in the position of the plasmon resonance peaks have indicated similar values for density and hydrogen content, in spite of variation of the experimental variables. The results of the electron probe microanalysis have shown that during the deposition in a chlorobenzene discharge chlorine was incorporated in the films which was very inhomogeneously distributed over the analysed film cross-section. Thus the chlorine species present in a chlorobenzene discharge appear to exercise an important influence on both the deposition process and the film properties.