Optimization of Ultrathin Carbon Overcoats on Hard Disk Media

Part of the Springer Theses book series (Springer Theses)


Reduction of the protective carbon overcoat (COC) thickness down to ≤2 nm on hard disk media is essential based on current perpendicular magnetic recording technology, in order to achieve areal densities of >1 Tb/in2. Because of its potential to achieve comparably higher sp3 carbon bonding and a denser carbon network, hence better film coverage at lower overcoat thicknesses, the filtered cathodic vacuum arc (FCVA) technique is a promising option for COC fabrication on future media. In addition, the ability to tune the energy of the incoming C+ ions is advantageous for optimizing the functional properties of the COC. In this chapter, the effects of C+ ion energy, thickness and the extent of atomic mixing on the microstructural and functional properties of ultrathin COCs are discussed, and how the FCVA process can be optimized to achieve the most desirable functional properties for the media.


  1. 1.
    M.A. Samad, E. Rismani, H. Yang, S.K. Sinha, C.S. Bhatia, Overcoat free magnetic media for lower magnetic spacing and improved tribological properties for higher areal densities. Tribol. Lett. 43, 247 (2011)CrossRefGoogle Scholar
  2. 2.
    M.A. Samad, S.M. Xiong, L. Pan, H. Yang, S.K. Sinha, D.B. Bogy, C.S. Bhatia, A novel approach of carbon embedding in magnetic media for future head/disk interface. IEEE Trans. Magn. 48, 1807 (2012)CrossRefGoogle Scholar
  3. 3.
    M. Abdul Samad, E. Rismani, W.M. Kwek, C.S. Bhatia, Energy gradient carbon embedding in the magnetic media for improved tribological performance. Surf. Coat. Technol. 242, 152 (2014)Google Scholar
  4. 4.
    S.N. Piramanayagam, C.T. Chong, Developments in data storage: materials perspective, 1st edn. (Wiley, New Jersey, NJ, USA, 2012)Google Scholar
  5. 5.
    E. Rismani, S.K. Sinha, S. Tripathy, H. Yang, C.S. Bhatia, Effect of pre-treatment of the substrate surface by energetic C+ ion bombardment on structure and nano-tribological characteristics of ultra-thin tetrahedral amorphous carbon (ta-C) protective coatings. J. Phys. D Appl. Phys. 44, 115502 (2011)CrossRefGoogle Scholar
  6. 6.
    R.J. Yeo, N. Dwivedi, L. Zhang, Z. Zhang, C.Y.H. Lim, S. Tripathy, C.S. Bhatia, Durable ultrathin silicon nitride/carbon bilayer overcoats for magnetic heads: the role of enhanced interfacial bonding. J. Appl. Phys. 117, 045310 (2015)CrossRefGoogle Scholar
  7. 7.
    J. Robertson, Ultrathin carbon coatings for magnetic storage technology. Thin Solid Films 383, 81 (2001)CrossRefGoogle Scholar
  8. 8.
    G.M. Pharr, D.L. Callahan, S.D. McAdams, T.Y. Tsui, S. Anders, A. Anders, J.W. Ager, I.G. Brown, C.S. Bhatia, S.R.P. Silva, J. Robertson, Hardness, elastic modulus, and structure of very hard carbon films produced by cathodic-arc deposition with substrate pulse biasing. Appl. Phys. Lett. 68, 779 (1996)CrossRefGoogle Scholar
  9. 9.
    D.G. Enos, L.L. Scribner, The potentiodynamic polarization scan. Solartron Analytical, Hampshire, UK, Technical Report 33, Jan 1997Google Scholar
  10. 10.
    Y. Wang, H. Li, L. Ji, F. Zhao, X. Liu, Q. Kong, Y. Wang, W. Quan, H. Zhou, J. Chen, The effect of duty cycle on the microstructure and properties of graphite-like amorphous carbon films prepared by unbalanced magnetron sputtering. J. Phys. D Appl. Phys. 43, 505401 (2010)CrossRefGoogle Scholar
  11. 11.
    S. Anders, A. Anders, I.G. Brown, B. Wei, K. Komvopoulos, J.W. Ager Iii, K.M. Yu, Effect of vacuum arc deposition parameters on the properties of amorphous carbon thin films. Surf. Coat. Technol. 68–69, 388 (1994)Google Scholar
  12. 12.
    N. Dwivedi, N. Satyanarayana, R.J. Yeo, H. Xu, K.P. Loh, S. Tripathy, C.S. Bhatia, Ultrathin carbon with interspersed graphene/fullerene-like nanostructures: a durable protective overcoat for high density magnetic storage. Sci. Rep. 5, 11607 (2015)CrossRefGoogle Scholar
  13. 13.
    D.J. Li, M.U. Guruz, C.S. Bhatia, Y.-W. Chung, Ultrathin CNx overcoats for 1 Tb/in2 hard disk drive systems. Appl. Phys. Lett. 81, 1113 (2002)CrossRefGoogle Scholar
  14. 14.
    N.W. Khun, E. Liu, M.D. Krishna, Structure, adhesive strength and electrochemical performance of nitrogen doped diamond-like carbon thin films deposited via DC magnetron sputtering. J. Nanosci. Nanotechnol. 10, 4752 (2010)CrossRefGoogle Scholar
  15. 15.
    C. Gao, Y.C. Lee, J. Chao, M. Russak, Dip-coating of ultra-thin liquid lubricant and its control for thin-film magnetic hard disks. IEEE Trans. Magn. 31, 2982 (1995)CrossRefGoogle Scholar
  16. 16.
    N.W. Khun, E. Liu, Investigation of corrosion behavior of nitrogen doped and platinum/ruthenium doped diamond-like carbon thin films in Hank’s solution. Mater. Sci. Eng. C 31, 1539 (2011)CrossRefGoogle Scholar
  17. 17.
    H.S. Zhang, K. Komvopoulos, Surface modification of magnetic recording media by filtered cathodic vacuum arc. J. Appl. Phys. 106, 093504 (2009)CrossRefGoogle Scholar
  18. 18.
    H.-S. Zhang, K. Komvopoulos, Synthesis of ultrathin carbon films by direct current filtered cathodic vacuum arc. J. Appl. Phys. 105, 083305 (2009)CrossRefGoogle Scholar
  19. 19.
    T.L. Barr, An ESCA study of the termination of the passivation of elemental metals. J. Phys. Chem. 82, 1801 (1978)CrossRefGoogle Scholar
  20. 20.
    M.C. Biesinger, B.P. Payne, A.P. Grosvenor, L.W.M. Lau, A.R. Gerson, R.S.C. Smart, Resolving surface chemical states in XPS analysis of first row transition metals, oxides and hydroxides: Cr, Mn, Fe, Co and Ni. Appl. Surf. Sci. 257, 2717 (2011)CrossRefGoogle Scholar
  21. 21.
    D. Briggs, M.P. Seah, Practical surface analysis by auger and X-ray photoelectron spectroscopy, 1st edn. (Wiley, Chichester, United Kingdom, 1983)Google Scholar
  22. 22.
    N.S. McIntyre, M.G. Cook, X-ray photoelectron studies on some oxides and hydroxides of cobalt, nickel, and copper. Anal. Chem. 47, 2208 (1975)CrossRefGoogle Scholar
  23. 23.
    V.I. Nefedov, D. Gati, B.F. Dzhurinskii, N.P. Sergushin, Y.V. Salyn, X-ray electron study of oxides of elements. Zh. Neorg. Khim. 20, 2307 (1973)Google Scholar
  24. 24.
    C.D. Wagner, W.M. Riggs, L.E. Davis, J.F. Moulder, Handbook of X-ray Photoelectron Spectroscopy, 1st edn. (Perkin-Elmer Corp. (Physical Electronics), Minnesota, 1979)Google Scholar
  25. 25.
    P. Marcus, J.M. Grimal, The anodic dissolution and passivation of NiCrFe alloys studied by ESCA. Corros. Sci. 33, 805 (1992)CrossRefGoogle Scholar
  26. 26.
    B. Stypula, J. Stoch, The characterization of passive films on chromium electrodes by XPS. Corros. Sci. 36, 2159 (1994)CrossRefGoogle Scholar
  27. 27.
    A.C. Ferrari, J. Robertson, Raman spectroscopy of amorphous, nanostructured, diamond-like carbon, and nanodiamond. Philos. Trans. R. Soc. Lond. Ser. A 362, 2477 (2004)CrossRefGoogle Scholar
  28. 28.
    P.M. Jones, J. Ahner, C.L. Platt, H. Tang, J. Hohlfeld, Understanding disk carbon loss kinetics for heat assisted magnetic recording. IEEE Trans. Magn. 50, 144 (2014)CrossRefGoogle Scholar
  29. 29.
    N. Wang, K. Komvopoulos, F. Rose, B. Marchon, Structural stability of hydrogenated amorphous carbon overcoats used in heat-assisted magnetic recording investigated by rapid thermal annealing. J. Appl. Phys. 113, 083517 (2013)CrossRefGoogle Scholar
  30. 30.
    A.C. Ferrari, Diamond-like carbon for magnetic storage disks. Surf. Coat. Technol. 180–181, 190 (2004)CrossRefGoogle Scholar
  31. 31.
    C.S. Bhatia, S. Anders, K. Bobb, R. Hsiao, I.G. Brown, D.B. Bogy, Ultra-thin overcoats for the head/disk interface tribology. J. Tribol. Trans. ASME 120, 795 (1998)CrossRefGoogle Scholar
  32. 32.
    B.K. Pathem, X.C. Guo, F. Rose, N. Wang, K. Komvopoulos, E. Schreck, B. Marchon, Carbon overcoat oxidation in heat-assisted magnetic recording. IEEE Trans. Magn. 49, 3721 (2013)CrossRefGoogle Scholar
  33. 33.
    S. Kundu, N. Dwivedi, N. Satyanarayana, R.J. Yeo, J. Ahner, P.M. Jones, C.S. Bhatia, Probing the role of carbon microstructure on the thermal stability and performance of ultrathin (<2 nm) overcoats on L10 FePt media for heat-assisted magnetic recording. ACS Appl. Mater. Interfaces. 7, 158 (2014)CrossRefGoogle Scholar
  34. 34.
    P.S. Goohpattader, N. Dwivedi, E. Rismani-Yazdi, N. Satyanarayana, R.J. Yeo, S. Kundu, C.S. Bhatia, Probing the role of C+ ion energy, thickness and graded structure on the functional and microstructural characteristics of ultrathin carbon films (<2 nm). Tribol. Int. 81, 73 (2015)CrossRefGoogle Scholar

Copyright information

© Springer Nature Singapore Pte Ltd. 2017

Authors and Affiliations

  1. 1.Department of Electrical and Computer EngineeringNational University of SingaporeSingaporeSingapore

Personalised recommendations