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-F2, 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. © 2007 Elsevier B.V. All rights reserved.