Piezoelectric Parylene-C MEMS microphone

There has long been a strong interest in the use of thin-film piezoelectric materials for MEMS microphones and actuators. However, well-known thin-film piezoelectric materials all have different degrees of technological difficulties for MEMS integration. Here, we demonstrated the first piezoelectric Parylene-C (PA-C) based MEMS microphone with a diaphragm 6mm in diameter and 30μm in thickness. The dynamic range spans from less than 30 dB to above 110 dB SPL and the open-circuit sensitivity is 1-110 μV/Pa over an audio frequency 1-10 kHz. The total harmonic distortion of the device is less than 20% at 110 dB SPL and 1 kHz.