Phase transformation of hydrogen free amorphous carbon films under ion beam bombardment Original Research Article

The features of hydrogen free tetrahedral amorphous carbon films (ta-C) prepared by radio frequency (RF) magnetron sputtering at room temperature, with a high portion of sp3 bonds, were examined by transmission electron microscopy. As grown specimens, presenting characteristic amorphous rings, were easily transformed to microcrystalline by low energy 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 SiC crystallites were detected in several specimens treated under similar bombardment conditions.