From VHF to UHF CMOS-MEMS monolithically integrated resonators

This paper presents the design, fabrication and characterization of microresonators exhibiting resonance frequencies in the VHF and UHF bands, fabricated using the available layers of the standard and commercial CMOS technology, AMS-0.35mum. The resonators are released in a post-CMOS process consisting on a maskless wet etching. A clamped-clamped beam with resonance frequency of 290 MHz exhibiting Q-factors of 970 in air and 2836 in vacuum is presented. The fabrication and design of a ring bulk acoustic resonator (RBAR) designed to operate at 1 GHz is described. Preliminary results on the electrical characterization show a resonance frequency of 1.04 GHz and a quality factor of 400 in air.