Quantifying High Temperature MEMS Micro Strain Relaxation Kinetics
High-temperature MEMS micro-strain relaxation follows stretched exponential kinetics driven by Coble creep, requiring in-situ Raman verification above 400°C.
Micro-Tensile Testing
Mechanical Evaluation
Characterization of the mechanical limits of thin films and microstructures involves applying a controlled axial force to a minute specimen until fracture occurs. This procedure is executed via micro-tensile testing, which reveals the elastic modulus, the yield strength, the ductility and the ultimate tensile strength of materials fabricated at the micron scale. The technique provides quantitative data that cannot be acquired through nanoindentation or bulk testing, enabling engineers to design micromachined components with high mechanical reliability.
Experimental Setup
Specimen mounting relies on electrostatic or pneumatic manipulators to align the microscale dog-bone sample with the loading axis. Aligning the specimen is critical, as any angular deviation introduces parasitic bending stresses that invalidate the measurement. Gripping forces must be carefully managed to prevent damage to the specimen.
Metrological Challenge
Precision displacement measurements require interferometric or high-resolution optical systems to track deformation across the gauge length. The load cells used in micro-tensile testing must resolve forces in the micronewton or millinewton range, making them highly sensitive to ambient vibration and temperature variations.
Material Behavior
Understanding how scaling affects deformation helps engineers predict the behavior of thin-film coatings and micromechanisms. Smaller volumes of material exhibit fewer internal defects, often leading to measured strengths that exceed those of corresponding bulk materials. This size effect influence directs the development of high-durability coatings for microelectronics.