Optimization of the electric field microsensor design based on FEM simulations

Abstract

In modern life, magnetic sensors are widely spread and based on many different principles. The miniaturized types like the GMR were first developed only for hard disk drives but triggered science applications in biology and medicine where they, e.g., allow detecting magnetic nano- and microbeads that are labeled with specific antibodies. In contrast to this, one can hardly find any electric field sensors. This is mainly because sensors need electrical conducting leads that disturb dramatically the electric field. The existing electric field sensors are limited in their applications due to their large and complex mechanical configurations. This lack of sensors is responsible for the insufficient knowledge about the interaction of electric fields with organisms or about their generation of fields. The treated novel electric field sensing principle uses micro-electro-mechanical systems (MEMS) technology with an optical readout to achieve a very small device that will enable mobile and precise measurements. At the end, this sensor will allow devices that could warn against thunderstorms or electrostatic discharges, and measure electric fields caused by animals and plants. Within the scope of this diploma thesis, the design of the MEMS transducer is optimized in order to maximize the sensitivity to electric fields and to minimize the risk of failure during the fabrication. Based on FEM simulations, various important characteristics are found and considered in the development of new chip designs. The novel geometries are implemented into the existing Python-code for generating the lithography masks of the individual layers. The fabrication of the new designs revealed further problems which should be considered in the development of the next chip generations.