Hydrogen plasma etching of diamond films deposited on graphite

Poly- and nanocrystalline diamond films have been deposited using microwave plasma enhanced CVD with gas mixtures of x%CH(4)/15%H(2)/Ar (x= 0.5,1, 3, and 5). After deposition the resulting films were exposed to a hydrogen plasma etching for 30 min. The hydrogen plasma produced preferential etching of non-diamond carbon on the surface of the samples and the development of steps and pits. Raman spectroscopy and X-ray photoelectron spectroscopy analyses on the etched films showed increased sp(3)/sp(2) ratio and decreased surface oxygen. The etch mechanism proposed is regression of pre-existing steps and step flow. (C) 2011 Elsevier B.V. All rights reserved.