The stress reduction effect by interlayer deposition or film thickness for diamond like carbon on rough surface

• Published in: Diamond and related materials 2010-05, Vol.19 (5), p.518-524
• Main Authors: Wei, Chehung, Yang, Jui-Feng, Tai, Fong-Cheng
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition; Diamond like carbon; Diamond-like carbon films; Exact sciences and technology; Film thickness; Finite element; Fullerenes and related materials; diamonds, graphite; Interlayer; Interlayers; Materials science; Physical properties of thin films, nonelectronic; Physics; Reduction; Specific materials; Stress reduction; Stresses; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thermal stability; thermal effects; Thermal stresses; Thin film structure and morphology
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2010.01.015

The effects of thermal stress resulting from thermal cooling for diamond like carbon (DLC) films on a rough surface are investigated by a finite element analysis. Two different schemes, interlayer deposition (metallic interlayer, multi-interlayer, grade interlayer) and film thickness increase are proposed to relieve the stress. The results show that the film thickness and coefficient of thermal expansion (CTE) are critical in stress reduction for a single interlayer. The metallic interlayer is effective in stress reduction only if the CTE of the interlayer is between that of the substrate and the film. Grade interlayer can further reduce the stress if the plasticity is graded in the interlayer. The increase of film thickness can also reduce the thermal stress, even though it is not as effective as the interlayer approach.