THE INFLUENCE OF STARVING PLASMA REGIME ON CARBON CONTENT AND BONDS IN A-SI1-XCX-H THIN-FILMS

Differences on carbon content and chemical bonds in a-Si1-xCx:H were o bserved and analyzed in carbon rich and silicon rich films, deposited by plasma enhanced chemical vapor deposition from mixtures of silane a nd methane. The influence of the radio frequency low power density reg ime on the film's properties was investigated. The content of Si, C, H in the solid phase was obtained by Rutherford back scattering and for ward recoil spectrometry. The bondings were analyzed by Fourier transf orm infrared spectroscopy. Quantitative analysis on the film's chemica l composition was performed combining the vibrational spectra with the stoichiometry data. The results showed that under ''silane starving p lasma'' conditions, a carbon content as high as 70 at. % is achieved a nd the main carbon bonds are tetragonal C-H, C-H-2, and Si-C. (C) 1998 American Institute of Physics. [S0021-8979(98)05717-X].