Nanoindentation studies of single-crystal (001)-, (011)-, and (111)-oriented TiN layers on MgO
- Thin Film Physics Division, Department of Physics, Linkoeping University, S-581 83 Linkoeping (Sweden)
- Division of Engineering Materials, Department of Mechanical Engineering, Linkoeping University, S-581 83 Linkoeping (Sweden)
- Department of Materials Science, the Coordinated Science Laboratory, and the Materials Research Laboratory, University of Illinois, 1101 West Springfield Avenue, Urbana, Illinois 61801 (United States)
The mechanical properties of (001)-, (011)-, and (111)-oriented MgO wafers and 1-{mu}m-thick TiN overlayers, grown simultaneously by dc magnetron sputter deposition at 700{degree}C in a mixed N{sub 2} and Ar discharge, were investigated using nanoindentation. A combination of x-ray-diffraction (XRD) pole figures, high-resolution XRD analyses, and Auger electron spectroscopy was used to show that all TiN films were single crystals with N/Ti ratios of 1.0{plus_minus}0.05. The nanoindentation measurements were carried out using a three-sided pyramidal Berkovich diamond indentor tip operated at loads ranging from 0.4 to 40 mN. All three orientations of MgO substrates, as-received, exhibited identical hardness values as determined using the Oliver and Pharr method. After a 1 h anneal at 800{degree}C, corresponding to the thermal treatment received prior to film growth, the measured hardness of MgO(001) was 9.0{plus_minus}0.3 GPa. All TiN films displayed a completely elastic response at low loads. Measured hardness values, which decreased with increasing loads, increased in the order (011){lt}(001){lt}(111). After a 30 s postdeposition anneal at 1000{degree}C, however, hardness was found to be independent of load except at displacements {gt}100 nm where substrate effects were apparent. TiN(001) and (111) films had hardnesses of 20{plus_minus}0.8 and 21{plus_minus}1 GPa, respectively, while data obtained from (011) layers exhibited large scatter due to surface roughness effects. Young{close_quote}s moduli for annealed samples, calculated from the elastic unloading curves, were found to be 307{plus_minus}15 GPa for MgO (001) and 445{plus_minus}38 and 449{plus_minus}28 GPa for TiN (001) and TiN (111), respectively. {copyright} {ital 1996 American Institute of Physics.}
- OSTI ID:
- 397420
- Journal Information:
- Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 12 Vol. 80; ISSN JAPIAU; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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