Improvement of fabrication and characterization methods for micromechanical disk resonators

In this paper we present a novel method to fabricate reliable micro-electro-mechanical system (MEMS) disk resonators with high yield and good performance. The key breakthrough in the fabrication process is a novel approach to effectively restraining electro-chemical corrosion of polycrystalline silicon (polysilicon) electrically coupled with noble metals of MEMS devices by hydrofluoric acid (HF)-based solutions. In addition, a measurement architecture based on a differential readout topology is demonstrated. The differential circuit proposed here can effectively suppress noise and feed-through current by common-mode rejection of the differential amplifier. This differential amplifier circuit configuration is also used to build up a notch filter. The preliminary result about the temperature dependence of the resonance frequency is discussed, and the device failure is analysed.