Fabrication Of Lithium Niobate Bulk Acoustic Resonator For 5G Filters

This work presents the fabrication of a MEMS resonant device which addresses the need for high quality and miniaturized RF filters in the 3-6 GHz range for 5th generation (5G) mobile networks. The 4-mask fabrication process is based on the definition of interdigitated Aluminum (Al) electrodes on a suspended membrane of 400 nm-thick Z-cut lithium niobate (LiNbO3). Devices are fabricated with a yield of 70% and exhibit high electromechanical coupling (k(t)(2)) and quality factor (Q) up to 28% and 300, respectively, for frequencies around 5 GHz.