Low-temperature flexible piezoelectric AlN capacitor integrated on ultra-flexible poly-Si TFT for advanced tactile sensing

Flexible piezoelectric sensors are now widely investigated for the implementation of highly conformable tactile systems such as electronic skin and they are based essentially on piezoelectric materials like PVDF and its copolymers. However, these sensing materials need long and high voltage procedure to increase their piezoelectric properties. Conversely, inorganic piezoelectric materials are difficult to grow or integrate on low temperature substrates (<300°C). In this work we propose a ultra-thin flexible tactile sensor based on polycrystalline silicon with low temperature aluminum nitride (160°C) acting as sensing element. AlN crystals orientation and morphological properties are shown. Moreover, sensor fabrication process and electromechanical characterization are reported.