Effect of Si incorporation on corrosion resistance of hydrogenated amorphous carbon film

Abstract

Effect of silicon (Si) addition on the chemical corrosion resistance of hydrogenated amorphous carbon (a-C:H) was investigated. Hydrogenated amorphous carbon and Si-incorporated a-C:H (a-C:H:Si) films were deposited by plasma-enhanced chemical vapor deposition using C2H2 and tetramethylsilane as source materials. Etching rates of these films in HNO3 and NaOH solutions were evaluated using surface plasmon resonance. Evaluation of etching rate in the NaOH solution showed that no etching occurred on the a-C:H film, although the a-C:H:Si film was etched by NaOH solution. From these results, corrosion of a-C:H and a-C:H:Si films in nitric acid progresses by the oxidization of sp2-hybridized bonded carbon. Also, Si-incorporation to a-C:H films improved the corrosion resistance by decreasing the ratio of sp2-hybridized bonded carbon. Si-incorporation to a-C:H films improved their robustness against corrosion in HNO3 solution by the formation of SiOx structures, while it reduced the corrosion resistance against NaOH solution.