Design,Fabrication And Testing Of MEMS Resonators And Gyroscopes

With the development of MEMS(microelectromechanical systems)technology,micro-resonators and micro-gyroscopes have been widely studied.The MEMS technology shows advantages on low cost,miniaturization and low power consumption.The technology has bright development and market future in civil applications such as car navigation,consumer electronics,mobile applications,aerospace and high-tech wars.As the key component of gyroscopes,the performance of resonators affects gyroscopes directly.The design,fabrication and testing of MEMS resonators and gyroscopes based on silicon and diamond are shown in this paper.The main work is discussed in this paper through the following five chapters.In chapter 1,the application field,research status and working principle of MEMS resonators and gyroscopes were introduced.MEMS resonators can be used in oscillators.MEMS vibrating gyroscopes can be categorized into gimbal gyroscopes,tuning-fork gyroscopes,vibrating-ring gyroscopes,multi-axis input gyroscopes,decoupling gyroscopes.The main research contents were introduced.In chapter 2,a MEMS 32kHz resonator and a DETF(double-ended tuning fork)resonator based on silicon were designed.And the working principles and structural designs were discussed.The resonant frequencies of the two resonators were obtained through finite element analysis(FEA)simulation in ANSYS.The fabrication process was developed.The vacuum testing platform was set and the resonant frequencies of the two resonators were tested.In chapter 3,the advantages of diamond MEMS sensors over silicon were discussed.Four diamond MEMS resonators(hemispherical and half-toroid resonators,32kHz resonator,DETF resonator)and a diamond MEMS vibrating gyroscope(vibrating-ring gyroscope)were designed.The working principle and structural design of each sensor was discussed.The resonant frequencies of the sensors were obtained through FEA simulation in ANSYS.In chapter 4,the fabrication process of diamond MEMS hemispherical and half-toroid resonators was developed.The six factors which affect HNA(HF-HNO3-acetic)isotropic etching were discussed.A custom equipment was designed to etch hemispherical and half-toroid molds.A Matlab image processing code was developed to process the individual images and extract the quantitative measurements of the finished features.Diamond films were deposited twice and the Raman spectra was obtained on the Boron doped UNCD(ultrananocrystalline diamond)film.The fabrication process of diamond MEMS in-plane sensors was designed.The parameters of each processing step were determined.The LDV(Laser Doppler Velocimetry)testing platform of DETF resonators was set and the resonant frequencies of the resonators based on silicon and diamond were tested.And the quality factors were calculated.In chapter 5,the main work of this paper was summarized briefly.Existing problems and shortcomings of this research were analyzed and future research proposals were suggested.