Surface smoothing of sputter deposited amorphous CNx films by silicon addition

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Original languageEnglish
Pages (from-to)3235-3240
Journal / PublicationJournal of Non-Crystalline Solids
Issue number27
Publication statusPublished - 1 Jun 2008


Amorphous carbon nitride (CNx) films with silicon addition up to 16 at.% are sputter deposited on Si(1 0 0) substrate, and the surface morphology is studied with scaling method based on atomic force microscopy. The surface roughness σ, the roughness exponent α, and the lateral correlation length ξ decrease with silicon content of the films, reaching 0.33 nm, 0.80 and 50 nm, respectively, for the film with [Si] = 16 at.%. The addition of silicon in the films leads to additional Si-N, Si-C-N and C{triple bond, long}N bonds revealed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The films undergo a structural transition from columnar to smooth morphology in cross-section with silicon addition demonstrated by field emission scanning electron microscopy. Nano-sized clusters sparsely dispersed in amorphous matrix of the film with [Si] = 16 at.% are observed by high-resolution transmission microscopy. According to the surface growth mechanism in which surface diffusion and geometrical shadowing drive structural and morphological evolution of the sputter deposited films, surface smoothing of the amorphous CNx films by silicon addition is explained by the formation of Si-N and Si-C-N bonds that impede surface diffusion of the adsorbed species during film growth, which leads to the reduced size of the columnar structures. © 2008 Elsevier B.V. All rights reserved.

Research Area(s)

  • Atomic force and scanning tunneling microscopy, Diamond-like carbon, Sputtering, UPS/XPS