Charge storage stability of SiO/sub 2/ film electret

The SiO/sub 2/ electret has received a lot of research attention recently. This important inorganic electret material emerged in 1980s. Besides having excellent charge storage stability, the SiO/sub 2/ electret is fully compatible with IC planar process and micro-mechanical processing technology because it is prepared on monocrystalline silicon wafer. Therefore, it has the advantage of integration and miniaturization of all kinds of electret transducers. Other commonly used polymer electret materials may not have this property. In this paper, the effects of silicon substrate materials, chemical surface treatments, and corona charging on charge storage stability of SiO/sub 2/ film electrets were studied. Some analyses and explanations based on these studies are given.