Alternative cleaning technique for the removal of carbon deposits

High efficiency for the removal of carbon coatings in narrow (1 mm) gaps and carbon films directly exposed has been found in He/O2 discharges, corresponding to >70% of the yield of directly exposed surfaces. Moreover, the absolute removal rate for the naked films was found to be 12 nm min [J.A. Ferreira, F.L. Tabarés, D. Tafalla, in: 12th ICFRM Conference, Santa Barbara, USA]. This has been associated to the different wall scenarios in the present work, leading to enhanced atomic recycling, of positive effect in the cleaning rate of the carbon films. Also, an alternative cleaning technique was studied, based on glow discharges in H2/N2. This is compared with He/O2. A high cleaning efficiency is also seen, based on the formation of high stable, N–C containing products. Finally, changes in carbon film composition by the addition of B have been identified as responsible for the much higher resistance of doped films against both types of cleaning plasmas.