Fabrication of bilayer plate for a micro thermal energy harvester

The fabrication process of a micro device introducing a new concept for thermal energy harvesting based on a two-step conversion is presented in this paper. An initially curved bilayer plate, which one of the layers is piezoelectric, is in contact with a hot source. The thermo-mechanical behavior leading to the buckling of the device is illustrated by finite elements simulations. The stresses generated by the buckling will create electrical charges through the piezoelectric effect, the piezoelectric layer being directly integrated to the device. The process flow for the employed bilayer structure aluminum nitride - aluminum will be detailed. The initial deflection of the plate was controlled by fabrication parameters during the thin films deposition. The first thermo-mechanical buckling was observed.