Mechanical characterization of sub-100-nm-thick Au thin films by electrostatically actuated tensile testing with several strain rates

We have developed the tensile testing device based on MEMS technology and applied it to the Au thin films with thickness in the sub-100-nm regime. The specimen was fabricated by thermal deposition and sputtering processes in the course of device fabrication. This technique of device fabrication in combination with the specimen realizes the precise loading direction without preloading before tensile tests. The loads were applied electrostatically by the comb-drive actuator. The obtained Young's modulus was 28 ± 3 GPa and was insensitive to the strain rate. The 0.2% yield strength was in the range from 192 to 519 MPa with a trend of decrease with decreasing strain rate in the range from 5 × 10−5 to 5 × 10−2 s−1.