Thermal treatments and gas adsorption influences on nanomechanics of ultra-thin silicon resonators for ultimate sensing

Miniaturization of mechanical components is the simplest method to minimize thermo-mechanical noise in various kinds of resonating sensors and nano-electromechanical systems (NEMSs). As the dimensions of a structure shrink, surface effects tend to dominate the bulk properties in mechanical quality factors (Q-factors). This paper presents findings on nanomechanical properties of ultra-thin single-crystal silicon (SCS) resonators, with emphasis on their surface effects, resulting from thermal treatments and gas adsorption. The measured Q-factors were found to be very sensitive to the surface conditions. This implies that the surface-related mechanism, or adsorption-induced surface stress, should be considered to explain the observed behaviour. The results obtained in this study provide an insight into the understanding of effects of thermal treatments and gas adsorption on nanomechanics of resonating elements, and provide further proof that thermal treatment is an effective method to achieve higher Q-factors for future nanoengineered devices for ultimate sensing.