Miniaturized Electrets

This paper describes the realization process of small-size electrets by using techniques generally applied in the fabrication of integrated circuits and microsensors. In the first part of the paper, attention is paid to the different electret decay mechanisms and their relative contribution to the overall stability of miniaturized electrets. Then, a process is described by which polymer electrets such as Teflon-FEP and PTFE can be deposited and shaped in a predefined pattern on a silicon wafer. In the third part, results on the application of new materials, especially silicon dioxide ( S i o s ) , for use in electret applications, are presented. It appears that after an appropriate treatment of the oxide surface, its charge-stability is at least equal to that of polymer electrets such as Teflon-FEP and PTFE.