Electret condenser

摘要

An electric condenser includes a fixed film 110 including a conductive film 118 to be an upper electrode, a vibrating film 112 including a lower electrode 104 and a silicon oxide film 105 to be an electric film, and a silicon oxide film 108 provided between the fixed film 110 and the vibrating film 112 and including an air gap 109 . Respective parts of the fixed film 110 and the vibrating film 112 exposed in the air gap 109 are formed of silicon nitride films 106 and 114.