Fig. 2 Cross-sectional microstructure of the as-deposited film. (A) Cross-sectional channeling contrast image showing the columnar microstructure of the deposited film. (B) Bright-field cross-sectional TEM micrograph. (C) Corresponding selected-area electron diffraction pattern indexed for matrix and twin orientations. (D) High-resolution TEM (HRTEM) image taken along the [011] zone axis and revealing high-density planar defects. (E) HRTEM image showing stacking faults and nanotwin lamellae on {111} planes. (F) Magnified view focusing on a few planar defects with better clarity (red, matrix; yellow, stacking fault; blue, twin).
Fig. 3 Tensile stress-strain curves of three Ni-Mo-W thin films from the current study compared with previously reported nanocrystalline Ni (11), nanocrystalline Ni-W alloy (12), nanotwinned Cu (13), and polysilicon thin films (14). The linear elastic response and ultrahigh strength are highly desirable for MEMS applications.
Fig. 4 Excellent thermal and mechanical stability of the Ni83.6Mo14W2.4 films. (A) Cumulative area fraction of the in-plane grain size of the Ni83.6Mo14W2.4 films annealed at various temperatures. (B) Cross-sectional TEM image of the film annealed for 1 hour at 600°C. FIB channeling contrast (C) and cross-sectional TEM image of a film that was loaded up to 3.1 GPa (D). No obvious changes in the columnar microstructure or twin size/spacing were observed.
- Table 1 Chemical composition, elastic modulus, tensile strength, hardness, and activation volume of the sputter-deposited Ni-Mo-W film obtained from WDS, microtensile, and nanoindentation tests.
Composition (at %) Elastic modulus (GPa) Tensile strength (GPa) Hardness (GPa) Activation volume (b3) 0.05 s−1 0.2 s−1 1 s−1 Ni83.6±0.2Mo14±0.2W2.4±0.1 221 ± 5 2.8 ± 0.3 8.95 ± 0.82 9.1 ± 0.91 9.24 ± 0.86 19.6
Supplementary Materials
Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/6/e1700685/DC1
Supplementary Materials and Methods
Supplementary Text
fig. S1. Scanning electron microscopy–EDS and XRD graph of the Ni-Mo-W film.
fig. S2. Yield strength predicted from the CLS model.
References (42–57)
Additional Files
Supplementary Materials
This PDF file includes:
- Supplementary Materials and Methods
- Supplementary Text
- fig. S1. Scanning electron microscopy–EDS and XRD graph of the Ni-Mo-W film.
- fig. S2. Yield strength predicted from the CLS model.
- References (42–57)
Files in this Data Supplement:
- Supplementary Materials and Methods
