Effects of plasma etching on DLC films

Magnetron sputtered diamond like carbon (DLC) films were etched in oxygen reactive ion etching (RIE) plasmas. The hydrogenated films etch 35% slower than the non-hydrogenated films. Etch rates increase with power. The anisotropy decreases with both pressure and power. Processes at 6.5 Pa yield anisotropies of over 0.9, with etch rates up to 185 nm/min for the hydrogenated films. Raman analysis indicates that these oxygen RIE processes etch preferentially non-crystalline carbon atoms in the hydrogenated films, the remaining film has more sp bound carbon atoms than the original DLC film. This phenomenon occurs in a much lesser degree for the non-hydrogenated films, and Raman analysis indicates that the sp(2)-bound carbon atoms etch at approximately the same rate as the non-crystalline bound atoms. (C) 1999 Elsevier Science S.A. All rights reserved.