PHASE-TRANSFORMATION OF HYDROGEN FREE AMORPHOUS-CARBON FILMS UNDER ION-BEAM BOMBARDMENT

The features of hydrogen free tetrahedral amorphous carbon films (ta-C ) prepared by radio frequency (RF) magnetron sputtering at room temper ature, with a high portion of sp(3) bonds, were examined by transmissi on electron microscopy. As grown specimens, presenting characteristic amorphous rings, were easily transformed to microcrystalline by low en ergy Ar ion beam bombardment. Characteristic polycrystalline rings on electron diffraction patterns, identified with a very good accuracy to the diamond reflections, revealed the phase transformation that takes place without any heating treatment under room temperature conditions . The crystallite grains size found to be up to 40 nm together with Si C crystallites were detected in several specimens treated under simila r bombardment conditions. (C) 1998 Elsevier Science Ltd. All rights re served.