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Journal Article
Attogram Mass Sensing based on Silicon Microbeam Resonators
- Authors
- In-Bok Baek, Sangwon Byun, Bong Kuk Lee, Jin-Hwa Ryu, Yarkyeon Kim, Yong Sun Yoon, Won Ik Jang, Seongjae Lee, Han Young Yu
- Issue Date
- 2017-04
- Citation
- Scientific Reports, v.7, pp.1-10
- ISSN
- 2045-2322
- Publisher
- Nature Publishing Group
- Language
- English
- Type
- Journal Article
- Project Code
- 17HS5600, The development of skin adhesive patches for the monitoring and prediction of mental disorders, Seunghwan Kim
- Abstract
- Using doubly-clamped silicon (Si) microbeam resonators, we demonstrate sub-attogram per Hertz (ag/Hz) mass sensitivity, which is extremely high sensitivity achieved by micro-scale MEMS mass sensors. We also characterize unusual buckling phenomena of the resonators. The thin-film based resonator is composed of a Si microbeam surrounded by silicon nitride (SiN) anchors, which significantly improve performance by providing fixation on the microbeam and stabilizing oscillating motion. Here, we introduce two fabrication techniques to further improve the mass sensitivity. First, we minimize surface stress by depositing a sacrificial SiN layer, which prevents damage on the Si microbeam. Second, we modify anchor structure to fiind optimal design that allows the microbeam to oscillate in quasi-one dimensional mode while achieving high quality factor. Mass loading is conducted by depositing Au/Ti thin films on the local area of the microbeam surface. Using sequential mass loading, we test effects of changing beam dimensions, position of mass loading, and distribution of a metal film on the mass sensitivity. In addition, we demonstrate that microbeams suffer local micro-buckling and global buckling by excessive mass loading, which are induced by two different mechanisms. We also find that the critical buckling length is increased by additional support from the anchors.
- KSP Keywords
- Critical buckling length, Fabrication techniques, Global buckling, High Sensitivity, High quality factor, Mass loading, Mass sensing, Mass sensor, Micro-scale, One-dimensional, Quality-factor(Q-factor)