Composition and chemical structure of ultra-thin a-C:F films deposited by RF magnetron sputtering with high pulsed bias

Abstract

By applying a negative high pulsed voltage to Si (111) substrates, ultra-thin fluorine carbon films of about 3 nm thick are deposited and completely covered on the samples by RF magnetron sputtering with PTFE target. Angle resolved X-ray photoelectron spectroscopy analysis indicates that the surface of the deposited films is rich in fluorine, and C–F 2, CF–CF and C–F groups in the outmost surface layer are much more than those in the inner layer of the films. The reason for this forming fluorine-rich phenomenon is explained and a two-layer model is proposed.