Many areas of life today already depend on the reliable, fully-automated operation of miniaturized systems. In the future, the networking of complex components will play an even greater role. However, until now, most of these decentralized systems have been powered via electrical lines or batteries. Because these concepts can only be used to a limited extent for site-independent networks or poorly accessible sensor positions, technology development, such as energy harvesting, is urgently needed to provide an alternative energy supply.
Energy harvesters can supply self-sustaining microsystems by collecting small amounts of energy from sources such as ambient temperature, light irradiation or vibration. Vibration-based harvesters, in particular, convert existing kinetic energy from the environment into electrical energy. Piezoelectric materials are especially suitable for the development of vibration-based harvesters by the direct mechanical-electrical conversion principle.
In the CONSIVA research project, the piezoelectric coefficient and the application potential of hafnium dioxide thin layers are to be evaluated at the Center Nanoelectronic Technologies (CNT) in Dresden. This material has ferroelectric and therefore piezoelectric properties and is qualified in microelectronics. Due to its high dielectric constant, it is already used in modern field-effect transistors.
In addition to the material development and the electromechanical characterization of active test structures, a harvester layout adapted to hafnium dioxide is to be conceptualized at the CNT. On the basis of these designs, Fraunhofer scientists want to illustrate new, concrete application scenarios for micro-energy harvesting. Dr. Wenke Weinreich, group leader at Fraunhofer IPMS explains, "Over the past few years, we have been able to gain extensive experience with the manufacturing, integration and optimization of ferroelectric hafnium dioxide for the most up-to-date storage applications. We see great potential to successfully use these experiences, especially in the field of energy harvesting. Thanks to these novel piezoelectric materials, we can decisively advance the miniaturization of vibration-based harvesters.”
The fields of application for energy-efficient microsystems are mainly found in medical and wireless sensor technology. The findings from the implementation of micro-energy harvesting technology can also be transferred to other fields of application in the Internet of Things (IoT).
The CONSIVA project is funded by the Development Bank of Saxony SAB (project number 100273858).
Fraunhofer Institute for Photonic Microsystems