Electrostatic actuator, droplet discharge head and method for manufacturing the droplet discharge head, droplet discharge apparatus, and device

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.