Nucleation and growth of Ti{sub 2}AlN thin films deposited by reactive magnetron sputtering onto MgO(111)

Journal Article · Mon Oct 01 00:00:00 EDT 2007 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2786871· OSTI ID:21062145

Beckers, M; Schell, N; Martins, R M. S.; Muecklich, A; Moeller, W; Hultman, L ^[1]

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1. Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf (FZD), P.O. Box 510119, 01314 Dresden (Germany)

The nucleation and growth of Ti{sub 2}AlN thin films on MgO(111) substrates during dual direct current reactive magnetron cosputtering from Ti and Al targets in an Ar/N{sub 2} atmosphere at a substrate temperature of 690 deg. C have been investigated. Time and thickness dependent in situ specular x-ray reflectivity and x-ray diffraction in combination with cross-sectional transmission electron microscopy and Rutherford backscattering spectroscopy reveal the formation of competing phases for slight N superstoichiometry with respect to Ti{sub 2}AlN. The stoichiometry deviations initiate the layer-by-layer growth of a {approx}380 A ring thick epitaxial N-substoichiometric cubic (Ti{sub 1-x}Al{sub x})N{sub y} layer. N-vacancy driven diffusion of Ti and Al leads to decomposition of this metastable solid solution into nanosized cubic TiN{sub y{sup '}} and AlN{sub y{sup ''}} domains as well as to a solid-state reaction with the MgO(111) by formation of a Mg{sub 2}(Al:Ti)O{sub 4} spinel, reducing the transformed (Ti{sub 1-x}Al{sub x})N{sub y} layer thickness down to {approx}60 A ring . Local AlN{sub y{sup ''}} domains serve as templates for Ti{sub 2}AlN nucleation at higher thicknesses. At the same time TiN{sub y{sup '}} and AlN{sub y{sup ''}} serve as a sink for excess gas phase N during the subsequent polycrystalline Ti{sub 2}AlN growth with random (Ti{sub 1-x}Al{sub x})N{sub y} renucleation as a tissue phase along Ti{sub 2}AlN grain boundaries. The individual Ti{sub 2}AlN grains with vertical sizes up to the total thickness retain local epitaxy to the substrate, with basal planes nonparallel to the substrate interface. Concurrently the (Ti{sub 1-x}Al{sub x})N{sub y} layer is further reduced by inward Ti{sub 2}AlN grain growth along the basal planes.

• OSTI ID: 21062145
• Journal Information: Journal of Applied Physics, Vol. 102, Issue 7; Other Information: DOI: 10.1063/1.2786871; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM NITRIDES
CRYSTAL GROWTH
DIRECT CURRENT
EPITAXY
GRAIN BOUNDARIES
GRAIN GROWTH
MAGNESIUM OXIDES
NANOSTRUCTURES
NUCLEATION
REFLECTIVITY
RUTHERFORD BACKSCATTERING SPECTROSCOPY
SOLID SOLUTIONS
SPUTTERING
STOICHIOMETRY
SUBSTOICHIOMETRY
THIN FILMS
TITANIUM NITRIDES
TRANSMISSION ELECTRON MICROSCOPY
VACANCIES
X-RAY DIFFRACTION