Realizing deep-submicron gap spacing for CMOS-MEMS resonators with frequency tuning capability via modulated boundary conditions

Abstract

Integrated CMOS-MEMS array resonators have been demonstrated that takes advantage of pull-in effect to surmount limitations of CMOS foundry process and attains electrode-to-resonator gap spacing at a deep-submicron range, leading to much smaller motional impedance compared to conventional CMOS-MEMS technologies, while possessing unique frequency tuning capability by modulating their mechanical boundary conditions. With the increase of applied dc-bias which simultaneously serves for functions of pull-in and resonator operation, the upward frequency shift of resonance caused by boundary condition (“BC”) change offers opposite tuning mechanism to well-known effect of electrical stiffness. As a result, frequency variation induced by BC-modulation and electrical-stiffness would yield a frequency-insensitive region under a certain dc-bias.