Synthesis and mechanical properties of amorphous carbon films by closed-field unbalanced magnetron sputtering

摘要

Amorphous hydrogen-tree carbon (a-C) films were synthesized by closed-field unbalanced magnetron sputtering (CFUBM). The deposition rate, structure, and mechanical properties of these films were studied as a function of applied bias voltage on substrate during deposition. The film structures were investigated in Raman spectroscopy, and surface roughness was analyzed by atomic force microscopy (AFM). The hardness and elastic modulus were evaluated by nanoindentation test. Raman analysis showed that sp~3/sp~2 ratio in a-C films increased with increasing substrate bias voltage. a-C films deposited at a bias of - 100 V exhibited a maximum hardness of 25 GPa.