Highly piezoresistive hybrid MEMS sensors

• Preparation of a highly piezoresistive CNT/SU-8 nanocomposite.
• Integration of this nanocomposite as piezoresistive transducer into polymeric MEMS.
• Development of an original MEMS design for sensitivity improvement.
• High sensitivity and reproducibility in MEMS sensor’ performance.

A flexible organic piezoresistive micro-electro-mechanical system (MEMS) strain sensor with enhanced sensitivity is presented. The piezoresistive transducers consist in CNT/SU-8 nanocomposites. The electrical resistance changes versus strain of CNT/SU-8 piezoresistive materials have shown linear and non-linear regions at low and high strain levels, respectively. The measurements have been correlated with an existing analytical model showing good agreement. This work also highlights the role of the MEMS design in the enhancement of the final sensing performance of the devices. The gauge factor calculated from the change of resistance as a function of applied strain has been found to reach 200 for optimized sensor geometries, providing highly sensitive piezoresistive strain sensors for flexible electronic applications.