XPS AND IR ANALYSIS OF THIN BARRIER FILMS POLYMERIZED FROM C2H4 CHF3 ECR-PLASMAS/

Thin fluorocarbon polymer films are prepared on PE-foils in low-pressu re electron cyclotron resonance plasmas using ethylene (C2H4) and trif luoromethane (CHF3) as monomers. The thin fluorinated hydrocarbon laye rs strongly reduces the permeability of polyethylene to alkanes. For e xample, the permeation of toluene was decreased by a factor of about 1 00 by a single, thin fluorocarbon layer. A further reduction of the pe rmeation down to a factor of 1600 can be obtained by a multilayer coat ing. X-ray photoelectron spectroscopy and Fourier transform IR spectro scopy are used to characterize the plasma polymerized films. It is sho wn that the addition of CHF3 to a C2H4 plasma leads to an increase of CF3-, CF2-, and CF- groups and to a decrease of CH3- and CH2- groups i n the film. The chemical composition of the polymer layers and their t oluene permeabilities are discussed. (C) 1997 John Wiley & Sons, Inc.