Nano-mechanical Behaviour and Microstructural Evolution of Cu/Si Thin Films at Different Annealing Temperatures


  • Woei-Shyan Lee
  • Tao-Hsing Chen
  • Chi-Feng Lin
  • Yu-Liang Chuang


Nanoindentation, Silicon, Microstructural evolution, Annealing temperature


This study investigates the nano-mechanical properties of as deposited Cu/Si thin films indented to a depth of 2000 nm using a nanoindentation technique. Cu films with a thickness of 1800 nm are deposited on (100) silicon substrates and the indented specimens are then annealed at temperatures of 160℃ and 210℃, respectively, using rapid thermal annealing (RTA) technique. The results show that the hardness and Young’s modulus of the Cu/Si thin films have maximum values of 0.82 GPa and 95 GPa, respectively. The TEM observations show that the specimens annealed at a temperature of 160℃, the amorphous nature of the microstructure within the indented zone is maintained. However, annealed at a higher temperature of 210℃, the indentation affected zone consists of Copper silicide (η-Cu3Si) precipitates are observed in the annealed specimens. Overall, the results presented in this study confirm that the annealing temperature has a significant effect on the formation of η-Cu3Si in nanoindented Cu/Si thin-film systems.


Y. Cao, C. Kim, S. R. Forrest and W. O. Soboyejo, “Patterning of active organic materials by direct transfer for organic electronic devices,” Journal of applied physics, vol. 98, pp. 033713, May 2005.

S. Majumder, N. E. McGruer, G. G. Adams, P. M. Zavracky, R. H. Morrison and J. Krinm, “Study of contacts in an electrostatically actuated microswitch,” Sensors and Actuators A: Physical, vol. 93 pp. 19-26, July 2001.

J. Plummer, M. Deal and P. Griffin, Silicon VLSI Technology: Fundamental, Practice and Modeling, New Jersey: Prentice Hall, 2000.

R. Saha and W. D. Nix, “Effects of the substrate on the determination of thin film mechanical properties by nanoindentation,” Acta Materialia, vol. 50, pp. 23-28, 2002.

J. Lou, P. Shrotriya, T. Buchheit, D. Yang, W. O. Soboyejo, “Nanoindentation study of plasticity length scale effects in LIGA Ni microelectromechanical systems structures,” Journal of Materials Research, vol. 18, pp 719-728, 2003.

A. C. Fischer-Cripps, Nanoindentation, Berlin: Springer-Verlag, 2002.

W. S. Lee and F. J. Fong, “Eutectic and Amorphous Phase Formation at Au/Cr/Si Thin Film Interface by Nanoindentation and Annealing,” Materials Transactions, vol. 48, pp. 2650-2658, 2007.

W. S. Lee and T. Y. Liu, “The effect of annealing temperature on the microstructure of nanoindented Au/Cr/Si thin films,” Nanotechnology, vol. 18, pp. 335701, 2007.

J. E. Bradby, J. S. Williams, J. Wong-Leung, M. V. Swain and P. Munroe, “Mechanical deformation in silicon by micro-indentation,” Journal of Materials Research, vol. 16, pp. 1500-1507, 2001.

V. Domnich and Y. Gogotsi, “Phase transformations in silicon under contact loading,” Reviews on Advanced Materials Science, vol. 3, pp. 1-36, 2002.

W. S. Lee and F. J. Fong, “Microstructural study of annealed gold–silicon thin films under nanoindentation,” Materials Science and Engineering A, vol. 475 pp. 319-327, 2008.

A. Cros, M. O. Aboelfotoh and K. N. Tu, “Formation, oxidation, electronic, and electrical properties of copper silicides,” Journal of applied physics, vol. 67, pp. 3328-3336, 1990.

R. J. Gutmann, T. P. Chow, A. E. Kaloyeros, W. A. Lanford and S. P. Muraka, “Thermal stability of on-chip copper interconnect structures,” Thin Solid Films, vol. 262, pp. 177-186, 1995.

M. Y. Park, J. H. Son and S. W. Rhee, “Chemical Vapor Deposition of Copper Thin Films with (hexafluoroacetylacetonate) Cu (allyltrimethylsilane),”Electrochemical and solid-state letters, vol. 1, pp. 32-33, 1998.

D. K. Kwak, H. B. Lee, J. W. Han and S. W. Kang, “Metalorganic chemical vapor deposition of copper on ruthenium thin film,” Electrochemical and solid-state letter, vol. 9, pp. C171-C173, 2006.

O. Azzaroni, M. Fonticelli, P. L. Schilardi, G. Benitez, I. Caretti, J. M. Albella, R. Gago, L. Vazquez and R. C. Salvarezza, “Silver electrodeposition on nanostructured gold: from nanodots to nanoripples,” Nanotechnology, vol. 15, pp. S197-S200, 2004.

M. F. sharin, A. Razak and Z. Zainal, “Electrophoretic deposition and characterization of copper selenide thin films,” The Malaysian Journal of Analytical Science, vol. 11, pp. 324-330, 2007.

W. C. Oliver and G. M. Pharr, “Improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments,” Journal of Materials Research, vol. 7, pp. 1564-1580, 1992.

R. E. Bouayadi, G. Regula, B. Pichaud, M. Lancin, C. Dubois and E. Ntsoenzok, “Gettering of diffused Au and of Cu and Ni contamination in silicon by cavities induced by high energy He implantation,” Physica Status Solidi B, vol. 222, pp. 319-326, 2000.

D. Christopher, R. Smith and A. Richter, “Atomistic modelling of nanoindentation in iron and silver,” Nanotechnology, vol. 12, pp. 372-383, 2001.

A. J. Leistner, A. C. Fischer-Cripps, J. M. Bennett, “ Indentation hardness and modulus of the surface of a large super-polished single crystal silicon sphere,” Proc. Int. Soc. Opt. Eng. (SPIE), Bellingharw, 5179 Optical Materials and Structures Technologies, 2003, pp. 215-222.

S. H. Hong, K. S. Kim, Y. M. Kim, J. H. Hahn, C. S. Lee, and J. H. Park, “Characterization of elastic moduli of Cu thin films usingnanoindentation technique”, Composites Science and Technology, vol. 65, pp. 1401-1408, 2005.

J. Wang-Leung, E. Nygren and J. S. Williams, “Gettering of Au to dislocations and cavities in silicon,” Applied Physics Letters, vol. 67, pp. 416-418, 1995.




How to Cite

W.-S. Lee, T.-H. Chen, C.-F. Lin, and Y.-L. Chuang, “Nano-mechanical Behaviour and Microstructural Evolution of Cu/Si Thin Films at Different Annealing Temperatures”, Int. j. eng. technol. innov., vol. 2, no. 3, pp. 207–215, Jul. 2012.