Bulk PZT Cantilever Based MEMS Acoustic Transducer for Cochlear Implant Applications

This paper presents the first acoustic experimental results of a MEMS based bulk piezoelectric transducer for use in fully implantable cochlear implants (FICI). For this purpose, the transducer was attached onto an acoustically vibrating membrane. Sensing and energy harvesting performances were measured using neural stimulation and rectifier circuits, respectively. The chip has a 150 Hz bandwidth around 1800 Hz resonance frequency that is suitable for mechanical filtering as a sensor. As an energy harvester, bulk piezoelectric transducer generated a rectified power of 16.25 μW with 2.47 VDC with 120 dB-A sound input at 1780 Hz. Among other MEMS acoustic energy harvesters in the literature, reported transducer has the highest power density (1.5 × 10−3 W/cm3) to our knowledge.