A miniaturized single-chip silicon membrane microphone with integrated field-effect transistor

A silicon microphone with integrated field-effect transistor which is fabricated on a single chip was simulated, designed and built. The oscillating single-crystal silicon membrane is structured using the electrochemical etch-stop technique with KOH solution. It contains the channel of the transistor. The gate electrode of the transistor is made of thick polysilicon provided with ventilation holes. The membrane sidelengths vary from 500 to 1000 mu m.