On-Chip Mechanical Characterization using an Electro-thermo-mechanical Actuator

A new micro-system for the on-chip mechanical characterization of thin polysilicon films was designed, fabricated and tested. The device contains a micro electro-thermo mechanical actuator which is able to load a specimen until rupture in purely tensile conditions. The elongation of the specimen is measured during the test through the capacitance variation of a set of parallel plate capacitors, while the force in the specimen can be computed starting from the applied voltage. Through a unique loading cycle in which the voltage is first increased until specimen rupture and then decreased, the new device allows for the determination of the specimen elastic stiffness and nominal tensile strength. The obtained experimental results were compared with values previously obtained by means of different on-chip test devices. Multi-physics FE simulations were performed for additional comparison with analytical formulae used in the data reduction procedure and with the obtained experimental results.