抄録
Micromachining of polytetrafluoroethylen (PTFE) and formation of crystalline thin PTFE films were carried out by direct synchrotron irradiation of a PTFE target in vacuum. The microstructures made in PTFE had the smallest surface detail down to less than ten microns and the largest structural height up to thousand microns. The maximum aspect-ratio was more than 20. The PTFE films which can preserve the chemical compositions, crystalline features and surface morphologies of the starting material, could be produced at low substrate temperatures with high deposition rates (200 Å/s). In situ mass spectrometric analysis of gaseous species evolved during the irradiation shows that, different from the laser ablation of PTFE for the deposition, the SR-induced reactions should be ablative photochemical decomposition (APD) rather than photothermal unzipping, yielding saturated fluorocarbons rather than monomers as the main gaseous products. Detection of a trace of CF3 in the deposited films by XPS and FTIR was consistent with our APD mechanism.
