The Microstructure and Properties of Tetrahedral Amorphous Carbon Films Deposited by Filtered Arc Accelerated at Different Energetic Grades

Tetrahedral amorphous carbon films were deposited on single crystalline silicon substrate by the species with the different impinging energetic grades produced by the static-electricity pulse negative bias from 0 to 2000 V. The microstructure of the ta-C films is the amorphous sp3 hybridization skeleton enchased with sp2 clusters whose inplane correlation length is less than 1 nm in light of visible Raman spectroscopic measurement. At the low energetic grade, the sp3-rich energetic window, and the sub-high energetic grade, the more is the content of sp3 in the films, the smoother is the surface of the films. The dependence between the impinging energy of the species and the surface morphology can be illustrated perfectly according to subimplantation growth mechanism. Nevertheless at the high energetic grade, the impinging ions with appropriate energy and angle can sputter and smoothen the surface, the roughness is even lower than the one of the films with the richest sp3. The hardness and Young's modulus of the films deposited at the high energetic grade (-2000 V) are higher than those of the films prepared at the floating conditions. Simultaneously, the critical scratching load of the films deposited with the substrate bias of 2000 V is even larger than the one of the sp3-rich films.