SIO2 ELECTRETS FOR ELECTRIC-FIELD GENERATION IN SENSORS AND ACTUATORS

Increasingly, electrostatic fields or forces play an important role in micromachined sensors or actuators. At the same time, there is a growing demand for permanently chargable insulators, called electrets, which may improve device characteristics considerably. In this paper, new results on SiO2 electrets are presented. It is shown that the volume of SiO2 can be charged positively at a certain depth to a certain amount by means of an electron beam. The method for measuring the mean spatial depth is described and a good long-term stability for the electret charges can be predicted from the results of thermally activated experiments.