METALLIZATION OF TEFLON PFA .1. INTERACTIONS OF EVAPORATED CR AND AL MEASURED BY X-RAY PHOTOELECTRON-SPECTROSCOPY

Cr and Al were evaporated onto Teflon PFA (polytetrafluoroethylene-co-perfluoroalkoxy vinyl ether) substrates by electron beam evaporation. In situ x-ray photoelectron spectroscopy revealed that Cr deposition leads to defluorination and the formation of fluoride and carbide species. The concentrations of fluoride and carbide increased with deposited Cr thickness, slowly at the initial stages of deposition but more rapidly afterwards. Al deposition was qualitatively similar to that of Cr, although the concentrations of fluoride and carbide formed were much lower. The sticking coefficients of both metals, low at the outset of metal deposition, were enhanced after initial deposition, with simultaneous increases in interfacial reactions. Oxygen contaminants in the form of metal oxides were observed, particularly in the case of Al.