Structural and electrical properties of co-sputtered fluorinated amorphous carbon film

Fluorinated amorphous carbon (a-C:F) films were deposited by co-sputtering process using polytetrafluoroethylene and graphite targets. The deposition characteristics, bonding configuration, structure, and electrical properties of a-C:F films were investigated as a function of fluorine content in the range of 0-62 at.%. As the fluorine content increased, transformation of bonding configuration and micro-structure were observed. For the fluorine content below 22 at.%, fluorine in amorphous carbon did not significantly affect hybrid bonding configuration. However, with increasing fluorine content, C - CF_x and C - CF₁ bonds were dominated and a further increase in fluorine content resulted in the formation of C - CF₂ and C - CF₃ bonds and then dielectric constant decreased from 10 to 2.7. Based on these results, correlations among bonds' distribution, micro-structure and dielectric property of a-C:F films were established.