EVALUATION OF THE ION-BOMBARDMENT ENERGY FOR GROWING DIAMOND-LIKE CARBON-FILMS IN AN ELECTRON-CYCLOTRON-RESONANCE PLASMA-ENHANCED CHEMICAL-VAPOR-DEPOSITION

The amorphous hydrogenated carbon (a-C:H) films were deposited on (100 ) silicon substrates using a divergent Ar + CH4 electron cyclotron res onance plasma. During the deposition sequence, the rf bias was applied to the substrate to increase the ion bombardment energy. The results of the microhardness test and the Raman spectroscopy revealed that the se films showed abrupt changes in the mechanical properties and in the bonding characteristics from polymerlike to diamondlike when the rf s ubstrate bias (V-sub) was increased to - 40 V. Such changes were attri buted to the structural and compositional modifications of the growing film by the bombarding ions. In addition, the results of the plasma d iagnostics and calculation showed that the required ion energy for gro wing a hard diamondlike carbon film was about 65 eV or higher. The bom bardment by high energetic ions caused the a-C:H film to have diamondl ike properties with a strong three-dimensional carbon network by dislo dging hydrogen atoms from CH3 radicals on the growing surface, as was identified by Fourier transform infrared spectroscopy. (C) 1998 Americ an Vacuum Society. [S0734-2101(98)01304-9].