Physical properties of epitaxial ZrN/MgO(001) layers grown by reactive magnetron sputtering

Journal Article · Fri Nov 15 00:00:00 EST 2013 · Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films

DOI:https://doi.org/10.1116/1.4825349· OSTI ID:22224117

Mei, A. B.; Zhang, C.; Sardela, M.; Eckstein, J. N.; Rockett, A. ^[1]; Howe, B. M. ^[2]; Hultman, L. ^[3]; Petrov, I.; Greene, J. E. ^[4]

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1. Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 (United States)
2. Air Force Research Laboratory, Wright Patterson Air Force Base, Dayton, Ohio 45433-7817 (United States)
3. Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping (Sweden)
4. Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 and Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping (Sweden)

Single-crystal ZrN films, 830 nm thick, are grown on MgO(001) at 450 °C by magnetically unbalanced reactive magnetron sputtering. The combination of high-resolution x-ray diffraction reciprocal lattice maps, high-resolution cross-sectional transmission electron microscopy, and selected-area electron diffraction shows that ZrN grows epitaxially on MgO(001) with a cube-on-cube orientational relationship, (001){sub ZrN}‖(001){sub MgO} and [100]{sub ZrN}‖[100]{sub MgO}. The layers are essentially fully relaxed with a lattice parameter of 0.4575 nm, in good agreement with reported results for bulk ZrN crystals. X-ray reflectivity results reveal that the films are completely dense with smooth surfaces (roughness = 1.3 nm, consistent with atomic-force microscopy analyses). Based on temperature-dependent electronic transport measurements, epitaxial ZrN/MgO(001) layers have a room-temperature resistivity ρ{sub 300K} of 12.0 μΩ-cm, a temperature coefficient of resistivity between 100 and 300 K of 5.6 × 10{sup −8}Ω-cm K{sup −1}, a residual resistivity ρ{sub o} below 30 K of 0.78 μΩ-cm (corresponding to a residual resistivity ratio ρ{sub 300Κ}/ρ{sub 15K} = 15), and the layers exhibit a superconducting transition temperature of 10.4 K. The relatively high residual resistivity ratio, combined with long in-plane and out-of-plane x-ray coherence lengths, ξ{sub ‖} = 18 nm and ξ{sub ⊥} = 161 nm, indicates high crystalline quality with low mosaicity. The reflectance of ZrN(001), as determined by variable-angle spectroscopic ellipsometry, decreases slowly from 95% at 1 eV to 90% at 2 eV with a reflectance edge at 3.04 eV. Interband transitions dominate the dielectric response above 2 eV. The ZrN(001) nanoindentation hardness and modulus are 22.7 ± 1.7 and 450 ± 25 GPa.

• OSTI ID: 22224117
• Journal Information: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films, Vol. 31, Issue 6; Other Information: (c) 2013 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0734-2101
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ATOMIC FORCE MICROSCOPY
COHERENCE LENGTH
DIELECTRIC MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRON DIFFRACTION
ELLIPSOMETRY
EPITAXY
HARDNESS
MAGNESIUM OXIDES
MAGNETRONS
MONOCRYSTALS
REFLECTIVITY
SPUTTERING
THIN FILMS
TRANSITION TEMPERATURE
TRANSMISSION ELECTRON MICROSCOPY
X RADIATION
X-RAY DIFFRACTION
ZIRCONIUM NITRIDES