CMOS micromachined capacitive cantilevers for mass sensing

Ying-Chung Li, Meng-Han Ho, Shi-Jie Hung, Meng-Huei Chen, Michael S-C Lu
2006 Journal of Micromechanics and Microengineering  
In this paper, we present the design, fabrication and characterization of the CMOS micromachined cantilevers for mass sensing in the femtogram range. The cantilevers consisting of multiple metal and dielectric layers are fabricated after completion of a conventional CMOS process by dry etching steps. The cantilevers are electrostatically actuated to resonance by in-plane electrodes. The mechanical resonant frequency is detected capacitively with on-chip circuitry, where the modulation technique
more » ... odulation technique is applied to eliminate capacitive feedthrough from the driving port and to lessen the effect of flicker noise. The highest resonant frequency of the cantilevers is measured at 396.46 kHz with a quality factor of 2600 at 10 mTorr. The resonant frequency shift after deposition of a 0.1 µm SiO 2 layer is 140 Hz, averaging 353 fg Hz −1 .
doi:10.1088/0960-1317/16/12/019 fatcat:hw6x5ssybjfvfl2i4eehasglim