Patent ID: 7581824

Claim:
An electrostatic actuator comprising: a cavity substrate having a diaphragm formed thereon; a glass electrode substrate on which a counter electrode is formed opposite to the diaphragm with a gap interposed therebetween, the glass electrode substrate being bonded to the cavity substrate; and an insulating film disposed on a surface of the cavity substrate facing the counter electrode, the diaphragm bending toward the counter electrode when voltage is applied, wherein, on the diaphragm, a dielectric film layer and a surface layer covering the dielectric film layer for reducing residual electric charges are laminated as the insulating film, the dielectric film layer being formed of silicon oxynitride, aluminum oxide, tantalum oxide, hafnium silicon nitride, or hafnium silicon oxynitride, the surface layer being formed of silicon oxide or silicon nitride, and at a bonded portion of the cavity substrate and the glass electrode substrate, a silicon oxide film without a dielectric film layer is formed as the insulating film, and the cavity substrate and the glass electrode substrate are anodically bonded with the silicon oxide film interposed therebetween.