Abstract
There are some related issues in the polytetrafluoroethylene (PTFE) coating techniques at
room temperature, such as poor adhesion of the coated films. Fluorocarbon (CxFy) films with
similar properties to PTFE such as high water repellency and low friction are obtained using the
sputtering deposition with a PTFE target. In this paper, the film-substrate adhesion of CxFy films
formed by RF unbalanced magnetron sputtering (RF-UBMS) method with a PTFE target is investigated. CxFy films were fabricated on Si substrates under different substrate-bias voltage. Tape-peeling test was performed to evaluate film-substrate adhesion of the films. Results revealed that the application of the substrate-bias voltage slightly reduced the film deposition rate. While CxFy films formed by applying a DC substrate-bias voltage of -50 V showed water repellency close to that of PTFE used as the target with excellent film-substrate adhesion. However, carbon-rich CxFy films were formed under an excessively high substrate-bias voltage of -100 V, exhibiting a decrease in water repellency of the film. This work proves that the application of an appropriate substrate-bias voltage could improve the adhesion between the formed film and the substrate in the sputtering deposition using a PTFE target.
