Abstract
A mask-free plasma etching process is described to fabricate 6 μm long submicron diamond rods (SDRs) in long conical shape. Polished polycrystalline diamond is etched in oxygen plasma ignited at a pressure of 10 mTorr by radio-frequency power of 100 W at 13.56 MHz. Each SDR is a bi-crystal, consisting of two diamond crystallites of micron size. The SDR is coated with a Fe 2 O 3 layer, as characterized by Auger electron spectroscopy, X-ray photoemission microscopy, and transmission electron microscopy. We propose that a "self-forming" mask of Fe 2 O 3 is generated during the etching process in which iron atoms sputtered from the substrate holder are deposited and oxidized on the diamond surface forming "micromask" that protects the underlying diamond and promotes the formation of SDRs. © 2011 Elsevier B.V. All rights reserved.