Abstract
The hardness and elastic modulus of ultra thin amorphous carbon overcoat (COC) films were measured using a recently developed sub-nm nanoindentation system. The carbon overcoat film thickness was varied to be 2.5 nm, 5 nm, and 10 nm on a glass substrate with a 2 nm titanium interlayer. A very sharp indenting tip, which was a cube corner tip with a radius of 44 nm, was used for the experiments. It was found that the mechanical properties of sub-10 nm film thicknesses can be reliably measured using the sub-nm indentation system and a sharp indenting tip. As the thickness of the carbon overcoat increased, so too did the surface roughness. For all three film thickness samples, the trends of hardness and elastic modulus values with the contact depth are very similar. When the contact depth is smaller than the film thickness, the measured values of hardness and elastic modulus are higher than those of the glass substrate, and gradually decrease and then approach the values of glass substrate. When the contact depth is larger than the film thickness, the measured values approximate those of the glass substrate. The thinner film shows higher values of hardness and elastic modulus near the surface, which indicates that mechanical properties do change with film thickness and that measurements made on thicker films and extrapolated to thinner films may lead to incorrect conclusions.
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References
T. Yamamoto, Y. Kasamatsu, and H. Hyodo: Advanced stiction-free slider and DLC overcoat. FUJITSU Sci. Tech. J. 37(2), 201 (2001).
P. Chaudhari: Information technology: A play of materials. MRS Bull. 27(7), 55 (2000).
B. Bhushan and X. Li: Nanomechanical characterization of solid surfaces and thin films. Int. Mater. Rev. 48(3), 125 (2003).
C. Charitidis and S. Logothetidis: Nanomechanical and nanotribological properties of carbon based films. Thin Solid Films 482, 120 (2005).
P. Lemoine, J.F. Zhao, J.P. Quinn, J.A. McLaughlin, and P. Maguire: Hardness measurements at shallow depths on ultra-thin amorphous carbon films deposited onto silicon and Al2O3-TiC substrates. Thin Solid Films 379, 166 (2000).
M.F. Doerner and W.D. Nix: A method for interpreting the data from depth-sensing indentation instruments. J. Mater. Res. 1, 601 (1986).
W.C. Oliver and G.M. Pharr: An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments. J. Mater. Res. 7, 1564 (1992).
Y. Cheng and C. Cheng: Scaling approach to conical indentation in elastic-plastic solids with work hardening. J. Appl. Phys. 84, 1284 (1998).
M. Kohzaki, A. Matsumuro, T. Hayashi, M. Muramatsu, and K. Yamaguchi: Preparation of carbon nitride thin films by ion-beam-assisted deposition and their mechanical properties. Thin Solid Films 308–309, 239 (1997).
T.W. Scharf, H. Deng, and J.A. Barnard: Nanowear/nanomechanical testing and the role of stress in sputtered CNx overcoats. J. Appl. Phys. 81(8), 5393 (1997).
Z. Xu and D. Rowcliffe: Finite element analysis of substrate effects on indentation behaviour of thin films. Thin Solid Films 447–448, 399 (2004).
H. Buckle: The Science of Hardness Testing and Its Research Applications (American Society for Metals, Metals Park, OH, 1973), pp. 453.
S. Logothetidis: Surface and interface properties of amorphous carbon layers on rigid and flexible substrates. Thin Solid Films 482, 9 (2005).
N. Yu, W.A. Bonin, and A.A. Polycarpou: High-resolution capacitive load-displacement transducer and its application in nanoindentation and adhesion force measurements. Rev. Sci. Instrum. 76, 045109 (2005).
E.V. Anoikin, M.M. Yang, J.L. Chao, and M.A. Russak: Magnetic hard disk overcoats in the 3–5 nm thickness range. J. Appl. Phys. 85(8), 5606 (1999).
K.J. Grannen, X. Ma, and R. Thangaraj: Ion beam deposition of carbon overcoats for magnetic thin film media. IEEE Trans. Magn. 36(1), 120 (2000).
T. Chudoba and F. Richter: Investigation of creep behaviour under load during indentation experiments and its influence on hardness and modulus results. Surf. Coat. Technol. 148, 191 (2001).
W.C. Oliver and G.M. Pharr: Measurement of hardness and elastic modulus by instrumented indentation: Advances in understanding and refinements to methodology. J. Mater. Res. 19(1), 3 (2004).
S. Butterworth: On the theory of filter amplifiers. Wireless Engineer. 7, 536 (1930).
K.J. Stout, P.J. Sullivan, W.P. Dong, E. Mainsah, N. Lou, T. Mathia, and H. Zahouani: The Development of Methods for the Characterization of Roughness in Three Dimension (Commission of the European Communities, Printed in Univ. of Birmingham, Report EUR 15178 EN, 1993).
A.Y. Suh and A.A. Polycarpou: Effect of molecularly thin lubricant on roughness and adhesion of magnetic disks intended for extremely high-density recording. Tribol. Lett. 15(4), 365 (2003).
G.W. Mbise, G.A. Niklasson, and C.G. Granqvist: Scaling of surface roughness in evaporated calcium fluoride films. Solid State Comm. 97(11), 965 (1996).
K.K. Nanda, S.N. Sarangi, and S.N. Sahu: Measurement of surface roughness by atomic force microscopy and Rutherford backscattering spectrometry of CdS nanocrystalline films. Appl. Surf. Sci. 133, 293 (1998).
H.N. Yang, Y.P. Zhao, G.C. Wang, and T.M. Lu: Noise-induced roughening evolution of amorphous Si films grown by thermal evaporation. Phys. Rev. Lett. 76(20), 3774 (1996).
Z.J. Liu, N. Jiang, Y.G. Shen, and Y.W. Mai: Atomic force microscopy study of surface roughening of sputter-deposited TiN thin films. J. Appl. Phys. 92(7), 3559 (2002).
F. Family and T. Vicsek: Scaling of the active zone in the Eden process on percolation networks and the ballistic deposition model. J. Phys. A 18, L75 (1985).
R.L. Schwoebel and E.J. Shipsey: Step motion on crystal surfaces. Appl. Phys. 37, 3682 (1966).
R.L. Schwoebel: Step motion on crystal surfaces. II. J. Appl. Phys. 40, 614 (1968).
J. Villain: Continuum models of crystal growth from atomic beams with and without desorption. J. Phys. (France) I 1, 19 (1991).
M. Siegert and M. Plischke: Slope selection and coarsening in molecular beam epitaxy. Phys. Rev. Lett. 73, 1517 (1994).
S.J. Bull and A.M. Korsunsky: Mechanical properties of thin carbon overcoats. Tribol. Int. 31(9), 547 (1998).
M. Lichinchi, C. Lenardi, J. Haugt, and K. Vitali: Simulation of Berkovich nanoindentation experiments on thin films using finite element method. Thin Solid Films 312, 240 (1998).
Z. Xu and D. Rowcliffe: Nanoindentation on diamond-like carbon and alumina coatings. Surf. Coat. Technol. 161, 44 (2002).
O.R. Monteiro: Thin film synthesis by energetic condensation. Annu. Rev. Mater. Res. 31, 111 (2001).
Y. Lifshitz: Diamondlike carbon—present status. Diamond Rel. Mater. 8, 1659 (1999).
S. Veprek and A. S. Argon: Mechanical properties of superhard nanocomposites. Surf. Coat. Technol. 146–147, 175 (2001).
D.C. Montgomery: Design and Analysis of Experiments, 5th ed. (John Wiley & Sons, New York, 2001), p. 96.
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Yeo, CD., Polycarpou, A.A., Kiely, J.D. et al. Nanomechanical properties of sub-10 nm carbon film overcoats using the nanoindentation technique. Journal of Materials Research 22, 141–151 (2007). https://doi.org/10.1557/jmr.2007.0007
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DOI: https://doi.org/10.1557/jmr.2007.0007