Sputtering of amorphous C:H and C/B:H layers by argon ions

A pulsed argon ion gun (with energies from 0.4 to 1.5 keV) was used to sputter (amorphous) a-C:H and a-C/B:H thin films. Velocity distributions of sputtered B, C, H and O atoms were measured by laser-induced fluorescence in the vacuum ultraviolet. Thompson distributions were fitted to these curves, giving surface energies of about 0.8 eV for H, 7.6 eV for C, and 5.6 eV for B atoms. The velocity distributions for atomic oxygen could not be fitted with a single value for the surface energy, but with the superposition of two Thompson distributions with different energies (0.5 and 4.8 eV). For H atoms, the sputtering yield shows a strong fluence dependence, which is considerably stronger for a-C:H than for a-C/B:H layers. (orig.)