Structure and mechanical properties of nitride-based superlattices with immiscible layers

Scott A Barnett*, Anita Madan, Ilwon W. Kim

*Corresponding author for this work

Research output: Contribution to conferencePaperpeer-review

Abstract

This paper reviews recent results on epitaxial Mo/NbN and AlN/TiN superlattices, deposited on MgO(001) using ultra-high vacuum reactive d.c. magnetron sputtering. A primary motivation for developing these new materials was to investigate nitride-based superlattices with immiscible layers, which should lead to more-stable structures with sharper interfaces than previously-studied superlattices, e.g. TiN/NbN. The high-pressure rocksalt structure of AlN was stabilized in epitaxial AlN/TiN(001) superlattices with AlN layer thickness ≤2.0 nm. The stable hexagonal phase was observed for AlN layer thickness >2 nm. The rocksalt structure formed at small layer thicknesses since it provided lower AlN/TiN interfacial energy than the hexagonal or zincblende structures. The epitaxial relationship between BCC Mo and rock-salt-NbN is Mo(001) ∥NbN(001), Mo[110]∥NbN[010], and the lattice mismatch is 1.4% given the 450 rotation about the (001). Kinematical model fits to x-ray diffraction data suggest that the interface widths were only ≈0.3 nm, presumably because of the immiscibility of Mo and NbN. Initial nanoindentation results indicate hardness values of ≈30 GPa, about 3 times the rule-of-mixtures value.

Original languageEnglish (US)
Pages189-201
Number of pages13
StatePublished - Jan 1 1998
EventProceedings of the 1998 TMS Annual Meeting - San Antonio, TX, USA
Duration: Feb 15 1998Feb 19 1998

Other

OtherProceedings of the 1998 TMS Annual Meeting
CitySan Antonio, TX, USA
Period2/15/982/19/98

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys

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