Mechanical and electrical properties of micron-thick nitrogen-doped tetrahedral amorphous carbon coatings

• Published in: Diamond and related materials Vol. 69; pp. 121 - 126
• Main Authors: Jang, Young-Jun, Kang, Yong-Jin, Kitazume, Kazutaka, Umehara, Noritsugu, Kim, Jongkuk
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-10-2016
• Subjects: Coatings; Electrical conductivity; Filtered cathode vacuum arc (FCVA); Hardness; Tetrahedral amorphous carbon (ta-C); Tetrahedral amorphous carbon (ta-C); Electrical conductivity; Filtered cathode vacuum arc (FCVA); Hardness; Coatings
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2016.08.001

The effect of nitrogen doping on the mechanical and electrical performance of single-layer tetrahedral amorphous carbon (ta-C:N) coatings of up to 1μm in thickness was investigated using a custom-made filtered cathode vacuum arc (FCVA). The results obtained revealed that the hardness and electrical resistance of the coatings decreased from 65±4.8GPa (3kΩ/square) to 25±2.4GPa (10Ω/square) with increasing nitrogen gas ratio, which indicates that nitrogen doping occurs through substitution in the sp2 phase. Subsequent AES analysis showed that the N/C ratio in the ta-C:N thick-film coatings ranged from 0.03 to 0.29 and increased with the nitrogen flow rate. Variation in the G-peak positions and I(D)/I(G) ratio exhibit a similar trend. It is concluded from these results that micron-thick ta-C:N films have the potential to be used in a wide range of functional coating applications in electronics.
Improved electrical resistance and high hardness of thick ta-C:N coating with nitrogen gas doping (20sccm) using filtered cathode vacuum arc technique. [Display omitted]
•One micron thick ta-C:N coatings were successfully deposited by FCVA.•The hardness of these coatings was controllable from 65 to 25GPa.•Their electrical resistance after nitrogen gas doping was 10Ω/square.•Nitrogen doping creates CC bonds with CNC groups.•Higher nitrogen concentrations reduce hardness but improve electrical resistance.