Thin plasma polymer layers were produced employing feed gas of CHF₃(trifluoromethane) and SiH₄ in an rf-plasma reactor respectively. The CHF₃ and SiH₄ were plasma-polymerized to yield films containing both fluorine and silicon residues. The plasma polymer membrane was investigated by elemental analysis, FT-IR(infrared spectroscopy), SEM(scanning electron microscopy) and XPS (X-ray photoelectron spectra) for physico-chemical analysis. The elemental composition of the formed polymers depended on the composition of the starting gases.