Effect of substrate bias on microstructure andproperties of tetrahedral amorphous carbon films

摘要

The microstructure and properties of tetrahedral amorphous carbon (ta-C) films deposited by thefiltered cathodic vacuum arc technology has been investigated by visible Raman spectroscopy,AFM and Nano-indentor. The Raman spectra have been fitted with a single skewed Lorentzianlineshape described by BWF function defining coupling coefficient, which characterizes the degreeof asymmetry and is correlated with the sp~3 content. When the substrate bias is –80 V, the sp~3content is the most and simultaneously the coupling coefficient is the least, following with theminimum root mean square surface roughness (R_q=0.23 nm) and the highest hardness (51.49 Gpa),Young’s modulus (512.39 Gpa), and critical scratching load (11.72 mN). As the substrate bias isincreased or decreased, the sp~3 content and other properties lower correspondingly.