Development of high-performance single-crystalline silicon condenser microphone

We have developed a high-performance silicon condenser microphone fabricated with a new process using single-crystalline silicon. Our fabrication process, requiring only two photolithography steps and two wet-etching steps, is simple and highly controllable, making it suitable for low-cost mass production. We designed, fabricated, and tested a prototype microphone, and the experimental results confirmed its excellent acoustical characteristics such as high sensitivity of -43.5 dB, wide frequency range of 30 Hz to 20 kHz, and wide dynamic range of 134 dB_SPL. The simulated and measured frequency responses showed excellent agreement, indicating the prototype was successfully fabricated as designed by our highly controllable process. These results show that it is feasible to economically mass-produce such high-performance microphones for purposes ranging from broadcasting to mobile communications