Phase change material programmable vias for switching and reconfiguration of Aluminum Nitride piezoelectric MEMS resonators

This paper reports on the first demonstration of an innovative approach to switching and reconfiguration of Aluminum Nitride (AlN) piezoelectric Micro Electro Mechanical System (MEMS) resonators using phase change material (PCM) programmable vias. A reconfigurable resonator prototype was fabricated by integrating 2 Ge₅₀Te₅₀ vias in the design of a 200 MHz contour-extensional mode resonator. The capability to reconfigure the device to operate in 3 different states, maintaining constant electromechanical performance (resonator figure of merit, FOM=k_t²·Q≈7) was demonstrated: (1) High Impedance state (resonator static capacitance, C₀≈660 fF, motional resistance, R_m≈225 Ω), (2) Low Impedance state (C₀≈1409 fF; R_m≈90 Ω), and (3) Short state (the resonator is reconfigured into a short circuit).