Temperature dependence of the chemical sputtering of amorphous hydrogenated carbon films by hydrogen

The temperature dependence of chemical erosion and chemical sputtering of amorphous hydrogenated carbon films due to exposure to hydrogen atoms (H-0) alone and combined exposure to argon ions and Ho was measured in the temperature range from 110 to 950 K. The chemical erosion yield for Ho alone is below the detection limit for temperatures below about 340 K. It increases strongly with increasing temperature, goes through a maximum around 650-700 K and decreases again for higher temperatures. Combined exposure to Ar+ and H-0 results in substantial chemical sputtering yields in the temperature range below 340 K. In this range the yield does not depend on temperature, but it increases with energy from about I (eroded carbon atoms per impinging Ar+ ion) to about 4 if the ion energy is increased from 50 to 800 eV. For temperatures above 340 K the measured erosion rates show the same temperature dependence as for the H-0-only case, but they are higher than for H-0-only. The difference between the Ar+ and H-0 and the H-0-only cases increases monotonically with increasing ion energy. (C) 2008 Elsevier B.V. All rights reserved.