Study on the Effectiveness of Different Electrode Geometries for Sputtered Aluminium Nitride-based MEMS Energy Harvesters

IoT (Internet of Things) paradigm depicts a scenario where thousands of elements are connected in a network accessible worldwide. To realize such ambitious scenario different research fields have to converge. One of the issues of such high scale network is its power demand typically solved by means of batteries. A promising approach to such a problem consists in harvesting energy from mechanical vibrations present in the environment. To efficiently convert the mechanical energy into useful electrical energy the design of the conversion element is fundamental. The electrodes have to be designed accordingly to the piezoelectric crystal orientation implemented in the device. This paper analyzes the performances of different electrode designs for Aluminum Nitride deposited by a magnetron sputtering process and presenting a strong c-axis orientation.