Selective Coating Deposition on High-Q Single-Crystal Silicon Resonators for the Investigation of Thermal Noise Statistical Properties

Silicon resonators are widely used in a large class of applications including sensing and actuation, signal processing and energy harvesting. Very often, the application for which these sensors are designed requires the deposition of metallic thin films or other coatings, in order to modify the optical coupling, the electrical conductivity or other physical-chemical properties of the device, for actuation and detection purposes. Invariably, coatings degrade the quality factor (Q) of resonance by increasing the amount of energy dissipated during vibration. Generally, this is an unwanted effect. In fact, developing strategies for controlling damping due to film deposition is vital for the design of high-performance resonators requiring low energy losses. In this paper, we present the results of our strategy for damping control applied to a class of high-Q silicon resonators used for the investigation of thermal noise statistical properties in non- thermodynamic equilibrium both at room temperature and at cryogenic temperatures.