Microfluidic encapsulated NEMS resonators for sensor applications

We present two novel methods to create microfluidic encapsulated nanoelectro mechanical (NEMS) resonator arrays. NEMS arrays were encapsulated in individually accessible parallel microfluidic channels defined in glass. The channels could be filled with fluid as well as evacuated to sub-millitorr pressures for optical measurement of resonant device motion. Each 200 nm thick silicon nitride NEMS resonator was 3 gm wide with lengths ranging from 5 to 10 gm. The demonstrated resonant frequencies ranged from 3 to 10 MHz with quality factors of up to 3,500 (under vacuum). These devices showed no stiction after repeated wetting and drying while in the channels. The presented work demonstrates an important step towards a chip level total analytical system using NEMS devices in applications such as mass based biosensors.