Structural effect on electronic sputtering of hydrogenated amorphous carbon films

A large erosion (∼105 atoms/ion) of C and H from hydrogenated amorphous carbon films (a-C:H) is observed due to the bombardment of 150 MeV Ag13+ ions. The erosion rate is monitored on-line by elastic recoil detection analysis (ERDA) technique. From the set of four samples under study, two films show erosion of both C and H, whereas, only H depletion takes place from the other two films. The observed variation in sputtering yield in different films is explained on the basis of structure and chemical environment of the films. It is shown in the framework of thermal spike model that the thermal energy confinement due to smaller cluster or domain sizes of the film influences the erosion. Structure of the films is revealed by Raman spectroscopy and is discussed on the basis of their Raman G and D modes.