Nanoindentation study of niobium nitride thin films on niobium fabricated by reactive pulsed laser deposition


Al Mamun M. A. , Farha A. H. , UFUKTEPE Y. , ELSAYED-ALI H. E. , Elmustafa A. A.

APPLIED SURFACE SCIENCE, cilt.330, ss.48-55, 2015 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 330
  • Basım Tarihi: 2015
  • Doi Numarası: 10.1016/j.apsusc.2014.12.144
  • Dergi Adı: APPLIED SURFACE SCIENCE
  • Sayfa Sayıları: ss.48-55

Özet

Nanomechanical and structural properties of NbNx films deposited on single crystal Nb using pulsed laser deposition for different substrate temperature were previously investigated as a function of film/substrate crystal structure (Mamun et al. (2012) [30]). In this study we focus on the effect of laser fluences and background nitrogen pressure on the nanomechanical and structural properties of NbNx films. The crystal structure and surface morphology of the thin films were tested by X-ray diffraction, scanning electron microscopy, and atomic force microscopy. Using nanoindentation, the investigation of the nanomechanical properties revealed that the hardness of the NbNx films was directly influenced by the laser fluence for low background nitrogen pressure, whereas the nanomechanical hardness showed no apparent correlation with laser fluence at high background nitrogen pressure. The NbNx film hardness measured at 30% film thickness increased from 14.0 +/- 1.3 to 18.9 +/- 2.4 GPa when the laser fluence was increased from 15 to 25 J/cm(2) at 10.7 PaN2 pressure. X-ray diffraction showed NbN, films with peaks that correspond to delta-NbN cubic and beta-Nb2N hexagonal phases in addition to the delta'-NbN hexagonal phase. Increasing the laser fluence resulted in NbN, films with larger grain sizes. (C) 2014 Elsevier B.V. All rights reserved.