Nanocrystalline Diamond Films Deposited by Two-Step Approach from CH₄/H₂ Microwave Plasma: The Influence of Reactor Pressure

Abstract:

The morphology, growth rate and atomic-bonding structure of nanocrystalline diamond films deposited on Si substrates were investigated under various pressures of the reactor. The films were deposited by CH₄/H₂ microwave plasma with two-step deposition and H₂-plasma cleaning processes. The pressures of 1, 2, 5, 9, and 25 kPa were used for deposition. In situ gas-phase species, including electron density, were monitored by an optical spectrometer and impedance analyzer. The films were characterized by SEM, Raman microscope, and white light reflectrometer. When the pressure increased, the surface smoothness and diamond grain size increased, amorphous carbon content decreased, and the intensity ratio of CH/H_β for the growth step increased. The growth rate was in proportional to the ratio of CH/H_β for the nucleation step but in inverse proportion to the electron density. The growth rates decreased from 370 nm/h for 1 kPa to 320 nm/h for 2 kPa. After that, the growth rate rapidly increased to 460 nm/h for 9 kPa, but it gradually decreased to 450 nm/h for 25 kPa. The film refractive indices were 2.16 for 5 kPa, 2.21 for 9 kPa, and 2.38 for 25 kPa. The films grown under 1 and 2 kPa showed highly light absorption.

• Periodical: Applied Mechanics and Materials (Volume 339)
• Pages: 657-664
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.339.657
• Online since: July 2013
• Authors: S. Tipawan Khlayboonme, W. Thowladda
• Keywords: Chemical Vapor Deposition (CVD), Nanocrystalline Diamond Film, Nanostructure, Plasma Impedance

References

[1] O.A. Williams: Diamond Related. Mater. Vol. 20 (2011), p.621

[2] S. Mitura, K. Mitura, P. Niedzielski, P. Louda and V. Danilenko: Journal of Achievements in Materials and Manufacturing Engineering Vol. 16 (2006), p.9

[3] O. Shenderova and G. McGuire, in: Nanocrystalline Diamond, edited by Y. Gogotsi CRC Press, New York (2006)

[4] H. Ye, C. Q. Sun, P. Hing, H. Xie, S. Zhang and J. Wei: Surf. Coat. Technol. Vol. 123 (2000), p.129

[5] P. W. May and Y. A. Mankelevich: J. Phys. Chem. C Vol. 112 (2008), p.12432

[6] A.C. Ferrari and J. Robertson: Phil. Trans. R. Soc. A Vol. 10 (2004), p.1098

[7] T. Sharda, T. Soga and T. Jimbo: J. Appl. Phys. Vol. 93 (2003), p.101

[8] F. Klauser, D. Steinmuller-Nethl, R. Kaindl, E. Bertel and N. Memme: Chem. Vap. Deposition Vol. 16 (2010), p.127

[9] A. Heiman, E. Lakin, E. Zolotoyabko and A. Hoffman: Diamond Related. Mater. Vol. 11 (2002), p.601

[10] J. G. Buijnsters, L. Vázquez, G. W. G. van Dreumel, J. J. ter Meulen,W. J. P. van Enckevort and J. P. Celis: J. appl. Phys. Vol. 108 (2010), 103514

DOI: 10.1063/1.3506525

[11] M. Moisan and J. Pelletier: Microwave Excited Plasmas, Elsevier Inc, Amsterdam, (1999)

[12] Y. Zhang and G. Chen: J. Vac. Sci. Technol. A Vol. 13 (1995), p.183

[13] F. J. Kampas: J. Appl. Phys. Vol. 54 (1983), p.2276

[14] M. Ikeda, H. Ito, M. Hiramatsu, M. Hori and T. Goto: J. Appl. Phys. Vol. 82 (1997), p.4055