Structural features of thick c-boron nitride coatings deposited via a graded B-C-N interlayer

K. Yamamoto, M. Keunecke, K. Bewilogua, Zs Czigany, L. Hultman

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

Thick c-BN films (up to 2.7 μm) were deposited onto Si substrates by an r.f. diode apparatus using boron carbide (B4C) targets. The c-BN films were deposited on a compositionally graded interlayer, which consisted of B, C and N. A thin B4C layer (~200 nm) had been initially deposited onto Si substrate in a pure Ar gas discharge. The following formation of the graded interlayer was conducted by the step-like or smoothly replacing Ar with N2 gas. Depending on the method implemented, the secondary ion mass spectroscopy (SIMS) depth profile showed relatively smooth or step-like changes in the elemental concentration of B, C and N. The primary analysis on the chemical bond of the graded interlayer was conducted by measuring the chemical shift of B1s, C1s and N1s spectra by X-ray photoelectron spectrometry (XPS). It is shown that the B-C bond, which was a major bonding component in the B4C layer, was gradually replaced by a mixture of B-N and C-C bond as the N2 fraction was increased. Transmission electron microscopy (TEM) images of the gradient layer showed that (0002) oriented turbostratic BN (t-BN) structure started to appear after the N2 concentration was increased by more than 2%. It was also observed that the c-BN phase nucleated non-uniformly in the gradient layer at 10% of N2 fraction.

Original languageEnglish
Pages (from-to)881-888
Number of pages8
JournalSurface and Coatings Technology
Volume142-144
DOIs
Publication statusPublished - Jul 1 2001

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Keywords

  • Graded interlayer
  • Si substrate
  • Structural features
  • c-Boron nitride films

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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