A high quality-factor silicon cantilever for a low detection-limit resonant mass sensor operated in air

The detection limit of a resonant cantilever mass sensor depends on its quality factor. The size and mode dependences of quality factors in silicon micro-cantilevers at atmospheric pressure are extensively investigated. Silicon micro-cantilevers of various lengths and widths are fabricated and their quality factors of flexural vibration modes are measured in air. The quality factor is found to vary largely depending on the cantilever length, width and vibration mode. The maximum quality factor obtained is 1550. These findings correlate well with a vibrating sphere model with an equivalent cross-section approximation.