Implantable MEMS Accelerometer Microphone for Cochlear Prosthesis

A MEMS accelerometer is proposed as an implantable middle ear microphone for future fully implantable cochlear prosthesis. Vibration characterization of human temporal bones by using laser Doppler vibrometer indicates that a MEMS accelerometer needs to achieve a sensing resolution of 75 μg/√Hz with a bandwidth of 10 kHz to detect normal conversation. A prototype MEMS accelerometer is designed and fabricated. When interfaced with a low noise CMOS capacitance-to-voltage converter, the sensor achieves a sensing resolution of 78 μg/√Hz at 500 Hz with a sensitivity of 11.5 mV/g and bandwidth of 6.4 kHz. The overall system attached on umbo demonstrates the capability of detecting normal conversation.