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

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 DG 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 DG 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 mm thick with diamond-like properties have been successfully grown. © 1999 Elsevier Science S.A. All rights reserved.