Microstructure and properties of tetrahedral amorphous carbon films deposited by filtered arc with accelerating at different energetic grades

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