Study on FN-DLC thin films：(Ⅲ) hydrophobic nature analysis

Abstract

Nitrogen doping of fluorinated diamond-like carbon (FN-DLC) films were deposited on p-type (100) silicon wafers at different deposition condition. The contact angle of water on the FN-DLC films surfaces was measured by a sessile-drop method. The surface morphology of films was characterized by atomic force microscopy (AFM). The Raman spectrum, infrared spectrum and X-ray photoelectron spectrum (XPS) demonstrate that the hydrophobic nature of FN-DLC films lies on chemistry structure, polarization intensity and roughness of films surface. As the ratio of sp3/sp2 decreases, the quantity of CF2 and roughness of film surface increases, thus contact angle increases. Otherwise, contact angle decreases. The contact angle is correlated with the deposition condition, which low temperature, low radio frequency power and high flux ratio r(r=CF4/［CF4+CH4］) brings the contact angle to ascend.