Observation of Micro-Tensile Behavior of Thin Film TiN and Au using ESPI Technique

Abstract

Micro-tensile properties of hard and soft thin films, TiN and Au, were evaluated by directly measuring tensile strain in film tension using the micro-ESPI(electronic Speckle Pattern Interferometry) technique. Micro-tensile stress-strain curves for these films were obtained and the properties were determined. TiN thin film 1 μm thick and Au films with two different thicknesses (t=0.5 μm and 1 μm) were deposited onto the silicon wafers, respectively, and micro-tensile specimens wide 50, 100 and 200 μm were fabricated using micromachining. In-situ measurement of the micro-tensile strain during tensile loading was carried out using the subsequent strain measurement algorithm and the ESPI system developed in this study. The micro-tensile curves showed that TiN thin film was a linear-elastic material showing no plastic deformation and Au thin film was an elastic-plastic material showing significant plastic flow. Effect of the specimen dimensions on mechanical properties was examined. It was revealed that tensile strengths for both films were slightly increased with increasing specimen width. Furthermore, variations of yielding strengths for the thin film Au with change of the dimension were investigated.

Synthesis of free-standing, curved Si nanowires through mechanical failure of a catalyst during metal assisted chemical etching

“…2c), which is a clear indication that necking took place prior to mechanical failure. This observation is consistent with results reported for studies on the mechanical properties of thin Au films 20 .…”

“…This observation is consistent with results reported for studies on the mechanical properties of thin Au films. 20 To obtain the desired arrays of curved nanowires, it is necessary to accurately designate the row of holes along which fracture should take place. To do this, we start by modelling a unit cell of the perforated Au film (schematic diagram shown in Fig.…”

OS5-1-2 Characterization of Small-volume Materials with Nanocontact Images

“…The yield strength of Au thin film was 590.9±36.7 MPa at 601.7 μN load and nearly constant regardless of the indentation depth. However, this value was about two times higher than the yield strength 243 MPa from the microtensile test [12]. The difference is attributed to unexpected elastic/plastic deformation in the Au thin film; since a hard Si substrate prohibits the indentation-induced radial plastic deformation, plastic flow occurs along lateral direction parallel to the interface.…”

“…The Japan Society of Mechanical Engineers NII-Electronic Library Service ATEM'07, JSME-MMD, Sep. [12][13][14]2007 from the extent of nanoindentation-induced plastic zone. The plastic zone radius P a was approximated as the boundary of material upheaved or pile-up region around the remnant indent and was measured by line profilings across the nanoindent.…”

“…In this paper, we combined a direct imaging and three-dimensional visualization technique for the resulting indent morphology. The yield strengths estimated from nanoindentation were compared with the results from previous microtensile testing [12] for the same thin film.…”