High-temperature stable piezoelectric aluminum nitride energy harvesters utilizing elastically supported diaphragms

High-temperature stable micromachined piezoelectric energy harvesters consisting of elastically supported aluminum nitride (AlN)/silicon carbide (SiC) composite diaphragms have demonstrated operation at temperatures up to 320°C. In particular, the elastically supported diaphragm harvester is shown to offer higher compliance and better power conversion than a clamped device previously reported in [1], and yields a 2.5× improvement in output power with lower resonance frequency. This work presents the first micromachined piezoelectric energy harvester with experimentally verified operation at elevated temperatures > 300°C, showing that the AlN/SiC piezoelectric energy harvesters have great potentials to serve as energy sources for high temperature wireless sensing applications.