The relations among the process, microstructure, and nanomechanical properties of cosputtered Ta–Si–N thin films have been investigated. The microstructure evolution and varied hardness and elastic modulus property of Ta–Si–N were influenced by nitrogen flow ratios [FN2% = FN2/(Far + FN2) × 100%] during cosputtering together with phase formation and the composition of films. The microstructure of Ta–Si–N formed at a low 2–10 FN2% was an amorphous-like phase with nanocrystalline grains embedded in an amorphous matrix, while polycrystalline Ta–Si–N was obtained at a high 20–30 FN2%. The cubic TaN phase or (Ta1–x,Six)N solid solution is much easier to form polycrystallites than noncubic Ta5Si3, Ta2Si, and Ta2N phases from grazing incidence x-ray diffractometry results. Amorphous-like Ta–Si–N films had much higher nanohardness, stiffness, elastic recovery percentage, and a closer boundary compared to polycrystalline films. A maximum nanohardness of 15.2 GPa was obtained at 3 FN2%. An increased hardness of polycrystalline films at 20–30 FN2% is attributed to the higher amount of the hard TaN phase.
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This work was partially sponsored by the National Science Council under Grant Nos. NSC 95-2221-E-006-047-MY3 and NSC 96-2628-E-006-080-MY3. We would like to express our sincere thanks to the microelectronic thin films laboratory for access to sputtering equipment. We also give great thanks to the Center for Micro/Nano Science and Technology (CMNST) and the Center for Precious Instruments at National Cheng Kung University, Tainan, Taiwan, for access to analysis equipment and technical support.
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Chung, C., Chen, T. Effect of nitrogen flow ratio on the microstructure evolution and nanoindented mechanical property of the Ta–Si–N thin films. Journal of Materials Research 23, 494–499 (2008). https://doi.org/10.1557/JMR.2008.0065