Stress relief of tetrahedral amorphous carbon films by post-deposition thermal annealing

• Published in: Surface & coatings technology Vol. 120; pp. 448 - 452
• Main Authors: Tay, B.K., Shi, X., Liu, E., Lau, S.P., Cheah, L.K., Sun, Z., Shi, J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.1999
• Subjects: Amorphous carbon; Cathodic arc; Raman spectroscopy; Stress relief; Cathodic arc; Amorphous carbon; Raman spectroscopy; Stress relief
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/S0257-8972(99)00465-X

The stress relief of tetrahedral amorphous carbon (ta-C) films by post-deposition thermal annealing was investigated. The films were subjected to rapid thermal annealing (RTA) for 2 min and conventional furnace annealing (CFA) for 30 min. In both cases, the films were annealed in vacuum with argon (4×10 −2 Torr) at successive higher temperatures ranging from 500 to 800°C. It was found that annealing by RTA achieved a greater stress reduction and a smaller change in the I D/ I G ratio (obtained from the Raman signal of the films) than annealing by CFA. For a ta-C film subjected to 700°C RTA, the stress decreases substantially by ∼90%, as compared to the ∼80% achieved by CFA. The I D/ I G ratio of the ta-C film subjected to 700°C RTA is 0.23 as compared to 0.27 for CFA. This suggests that a higher stress relief of ta-C films can be better achieved by a shorter annealing time without sacrificing much degradation in their diamond-like properties. Subsequent deposition and annealing steps to deposit thicker films were carried out. Films up to 0.8 μm thick with diamond-like properties have been successfully grown.