Patterning of SiO2/Si3N4 electret

Patterning of electret layers is required for a plurality of technical applications such as micromotors, transducers and energy scavengers, however, the electrets patterned for such devices using photolithography show rapid charge decay in narrow patterned structures. In this work, the technology for SiO₂/Si₃N₄ electret developed earlier is modified for making its narrow lines, down to 20 mum. The structures show no dependence of charge retention on line width as measured 1 year after fabrication.