The influence of substrate temperature and Al mobility on the microstructural evolution of magnetron sputtered ternary Ti-Al-N thin films

Journal Article · Tue Sep 15 00:00:00 EDT 2009 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3208065· OSTI ID:21361849

Beckers, M ^[1]; Hoeglund, C; Hultman, L ^[2]; Baehtz, C; Martins, R M. S.; Moeller, W ^[1]

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1. Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany)
2. Department of Physics, Chemistry and Biology (IFM), Thin Film Physics Division, Linkoeping University, Linkoeping SE-581 83 (Sweden)

Ternary Ti-Al-N films were deposited onto Al{sub 2}O{sub 3} (0001) substrates by reactive cosputtering from elemental Ti and Al targets and analyzed by in situ and ex situ x-ray scattering, Rutherford backscattering spectroscopy, transmission electron microscopy, and x-ray photoemission spectroscopy. The deposition parameters were set to values that yield Ti:Al:N ratios of 2:1:1 and 4:1:3 at room temperature. 2TiAlN depositions at 675 deg. C result in epitaxial Ti{sub 2}AlN growth with basal planes parallel to the substrate surface. Nominal 4TiAl3N depositions at 675 deg. C and above, however, yield domain growth of TiN and Ti{sub 2}AlN due to Al loss to the vacuum. Depositions at a lower temperature of 600 deg. C yield films with correct 4:1:3 stoichiometry, but Ti{sub 4}AlN{sub 3} formation is prevented, supposedly by insufficient adatom mobility. Instead, an incoherent Ti{sub n+1}AlN{sub n} structure with random twinned stacking sequences n is obtained that exhibits both basal plane orientations parallel and nearly perpendicular to the substrate interface. X-ray photoemission spectroscopy shows that in contrast to stoichiometric nitrides the Al is metallically bonded and hence acts as twinning plane within the Ti{sub n+1}AlN{sub n} stackings. Domains with perpendicular basal plane orientation overgrow those with parallel orientation in a competitive growth mode. The resulting morphology is a combination of smooth-surface parallel-basal-plane-oriented domains interrupted by repeated facetted hillocklike features with perpendicular basal plane orientation.

• OSTI ID: 21361849
• Journal Information: Journal of Applied Physics, Vol. 106, Issue 6; Other Information: DOI: 10.1063/1.3208065; (c) 2009 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
CRYSTAL GROWTH
EPITAXY
MICROSTRUCTURE
MORPHOLOGY
PHOTOEMISSION
RUTHERFORD BACKSCATTERING SPECTROSCOPY
SPUTTERING
STOICHIOMETRY
SUBSTRATES
TEMPERATURE RANGE 0273-0400 K
THIN FILMS
TITANIUM NITRIDES
TRANSMISSION ELECTRON MICROSCOPY
VACUUM COATING
X-RAY DIFFRACTION
X-RAY PHOTOELECTRON SPECTROSCOPY
ALUMINIUM COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
CRYSTAL GROWTH METHODS
DEPOSITION
DIFFRACTION
ELECTRON MICROSCOPY
ELECTRON SPECTROSCOPY
EMISSION
FILMS
MICROSCOPY
NITRIDES
NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
PNICTIDES
SCATTERING
SECONDARY EMISSION
SPECTROSCOPY
SURFACE COATING
TEMPERATURE RANGE
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS