Excimer Laser Interactions with Ptfe Relevant to thin Film Growth

Abstract

AbstractRecently, thin films of polytetrafluroethylene (PTFE) have been grown using pulsed laser ablation of TeflonTM at 266 nm.1,2 To provide further insight into the growth mechanisms we have examined the neutral and charged particle emissions generated in vacuum by 0 - 3 J/cm2 pulses of 248 nm radiation incident on solid PTFE. Measurements include quadrupole and time-of-flight mass spectroscopy. We find in addition to the neutral monomer (C2F4), copious emissions of highly reactive neutral and charged radicals, e.g., CF2, CF3, CF, F, and Cx. A careful analysis of the fluence dependence of these products provides definitive evidence that their precursors are generated by a thermally driven unzipping reaction. Models for the production of the radical species with the observed energies (several eV) involving gas phase processes are presented. Implications for improving PTFE thin film growth will be discussed.