GaN: A multifunctional material enabling MEMS resonators based on amplified piezoelectric detection

The properties of a new class of electromechanical resonators based on GaN are presented. By using the flexural modes of a doubly clamped beam, the two-dimensional electron gas (2-DEG) present at the AlGaN/GaN interface can be modulated by a field effect arising from the GaN buffer piezoelectricity. This leads to active piezoelectric transducers for which we show experimental results with detailed bias condition studies up to 10 MHz. Associated with modeling of the transduction physics, this allows explaining how the 2-DEG properties lead to the transconductance effect in the electromechanical domain.