Unusual morphology of CVD diamond surfaces after RIE

Reactive ion etching of (100) CVD diamond films in 02 has been performed using a 13.56 MHz capacitively coupled reactor at pressures of 20 mTorr-100 mTorr and r.f. powers of 100 W-300 W. The formation of columnar structures was observed at the grain boundaries whereas the (100) facets were etched to yield a smooth surface under optimum conditions. For comparison, the RIE of single, isolated cubo-octahedral crystallites produced smooth (100) facets and roughened (111) surfaces reminiscent of the micro-columnar structures evident in the films. (C) 2008 Elsevier B.V. All rights reserved.