Design and Performance of Aluminum Nitride Piezoelectric Microphones

Micro-electro-mechanical (MEMS) microphones (mics), utilizing capacitive transduction technology, have entered the cellular handset marketplace and are experiencing rapid growth. MEMS mics offer size and assembly advantages and are expected to capture a significant market share by 2008. Given the market potential, MEMS mic technology is an active area of research and development. This paper presents the performance of a series of different piezoelectric mic designs. Piezoelectric mics may offer advantages such as moisture tolerance, higher maximum sound pressure level, and dynamic range. Piezoelectric mics have been studied previously, and include both lead zirconium titanate (PZT) and zinc oxide (ZnO) based devices; whereas, this paper examines performance of different mic designs using an aluminum nitride piezoelectric. Finite-element simulation and measured results are shown.