Piezoelectric actuated epitaxially grown AlGaN/GaN‐resonators

Abstract

AbstractIn this work we present a novel concept of piezoelectrically actuated MEMS resonators based on AlGaN/GaN‐heterostructures. The 2DEG, which is confined at the AlGaN/GaN interface, serves as back electrode for piezoelectric actuation and read‐out. Using the inverse piezoelectric effect longitudinal in‐plane mechanical oscillations could be exited by applying a RF signal to the drive contacts. Through the charges, which were generated by the direct piezoelectric effect a sensor signal could be detected at the sense contacts of the integrated resonator structure. This enables the measurement of longitudinal resonant frequencies up to the 4th mode with values from 3 to 63 MHz. The investigations were carried out in various ambient pressure conditions, which exemplarily demonstrate the sensitivity of the quality factor to environmental parameters. Thereby the AlGaN/GaN‐resonators showed the highest sensitivity in the region of viscous damping, which leads to the possibility of sensor applications concerning the property determination of gaseous or even liquid surrounding conditions. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)