Short Communication: Stable DRIE-patterned SiO2/Si3N4 electrets for   electret-based vibration energy harvesters
  This paper is about a new manufacturing process aimed at developing stable SiO2/Si3N4 patterned electrets using a Deep Reactive Ion Etching (DRIE) step for an application in electret Vibration Energy Harvesters (VEH). Electrets charged by a positive corona discharge show excellent stability with high surface charge density that can reach 5mC/m^{2} on 1.1\mum-thick layers, even with fine patterning (down to 25\mum) and harsh temperature conditions (up to 250{\deg}C), paving the way to new electret VEH designs and manufacturing processes. 
S. Boisseau, A. B. Duret, G. Despesse, J. J. Chaillout, J. S. Danel,   A. Sylvestre
cond-mat.mtrl-sci