Switchable Transduction in GAN MEMS with Off-State Shunt

This work presents a switchable MEMS resonator in an AlN/GaN heterostructure targeted for reconfigurable RF components in next generation programmable radios. The carrier density of a 2D electron gas (2DEG) is set by a Schottky control gate out of line with the RF signal. When a negative bias voltage applied to the control gate is larger than the threshold voltage, the 2DEG channel is depleted allowing an RF signal launched by Ohmic interdigitated transducers (IDTs) to effectively transduce S
_o
Lamb mode resonance at 995 MHz. Unique to this transducer design, mechanical transduction is completely blocked by a shunted path created by a 2DEG in the OFF state. This is the first characterization of a resonator with such off-state shunt transduction. Equivalent circuit models for ON and OFF states were developed and parameters were extracted from fitting to measurement. At ON state, the resonators demonstrated maximum f.Q product of 5×10
¹²
s
^-1
m and FOM of 5.18.