Abstract
We developed a silicon electret condenser microphone (ECM) fabricated with the micro-electro-mechanical systems (MEMS) process using single-crystalline silicon. A silicon ECM has a SiO2/Si3N4 inorganic electret film (permanently charged dielectric) within microphone element, and it can remove 48-V bias voltage. We confirmed that a prototype microphone operated with 3-V or 1.5-V power supply had excellent acoustic characteristics. Experimental results also show that developed silicon-based electret had high heat and humidity resistance. We conclude that it is feasible to use such low-voltage high-performance MEMS microphones for a wide range of applications such as broadcasting, hearing-aids, and mobile communications.
