Inorganic electret layers for miniaturized devices

Due to their internal charges, electrets provide a variety of effects such as external fields, generation of forces, and more. Based on these effects electrets are an important component in many applications in the field of sensors and actuators. At present, research is carried out on micromachined devices manufactured completely with the standard steps of silicon technology. Therefore the electret properties of some silicon based inorganic dielectrics have been investigated with different methods which will be described briefly. In addition the mechanical properties of the electret layers have been considered. According to the experimental results which will be reported and discussed, double layers of silicon dioxide and nitride demonstrate improved properties compared to well investigated single layers. Therefore these seem to be interesting electret materials for applications in micromechanical devices.