Research On Key Technologies Of Moems Scanning Grating Mirror Based On Tilted(111) Silicon Wafer

A MOEMS scanning grating mirror is the critical component in near infrared(NIR)micro-spectrometer systems.The diffraction efficiency,resolution,scanning angle and stability of MOEMS scanning grating mirror makes an important impact to NIR micro-spectrometer.Thus,the research on the key technologies of MOEMS sanning grating mirror integrated with spectral,scanning and sensing function,is of great scientific significance and application requirements.In order to satisfy the application requirements of high diffraction efficiency and monitoring the state of scanning mirror in a low-cost way,a novel MOEMS scanning grating mirror device based on a tilted(111)silicon wafer was presented in this thesis.The researches about the theory,design,fabrication and experimental test on MOEMS scanning grating mirror were performed.The key technologies for the intergrating design and fabrication of blazde grating,scanning mirror and angle sensor on a tilted(111)silicon wafer were broken through.The prototype of MOEMS scanning grating mirror was developed.The experimental test platform of optical properties and electromechanical properties was built up,and the performance of MOEMS scanning grating mirror prototypes was tested and analyzed.The main content of this thesis is:(1)The research status of MOEMS scanning grating mirror,especially the diffraction efficiency and the measurement of the scanning angle were analyzed.The science and technology problems of MOEMS scanning grating mirror were studied.(2)A novel MOEMS scanning grating mirror model on a tilted(111)silicon wafer was proposed.The optical properties of grating was analysis.The movements of the model,the electromagnetic acruator model and the electromagnetic angle sensor model were proposed.(3)The technical indicators for the proposed MOEMS scanning grating mirror were determined according to the application requirements of NIR micro-spectrometer.Mechanical vibration theory was used to analyzed the vibration model of the MOEMS scanning grating mirror.Electromagnetic theory was used to analyzed the performance of electromagnetic acruator and electromagnetic angle sensor.After analysis and calculation,the optimized structrure parameters were designed.(4)The photoetching mask layout and the fabrication process were designed.The anisotropic etching was used to form the groove of blaze grating.In order to improve the diffraction efficiency,oxidation process was used to reduce the ridge on the top of grating groove.The compatibale processing technology of blaze grating,micro-mirror and metal coil was broken through,and the experimental prototype of the MOEMS scanning grating mirror was obtained.(5)The experimental test method of the MOEMS scanning grating mirror was investigated.Experimental results show that the resonance frequency of the fabricated MOEMS scanning grating mirror is 550.58 Hz,the diffraction efficiency of the-1st order can reach 71% and the resolution can reach 18 nm at the wavelength of 1392 nm.When the driving voltage is 1000 mV,the scanning angle of the MOEMS scanning grating mirror can reach to ±6.34° at resonance frequency.The output voltages of angle sensor have a good linear relationship with the scanning angle of mirror.The sensitivity of the angle sensor is 0.9654mV/° without amplifying.The theoretical analysis and experimental results have showed that the MOEMS scanning grating mirror has high performance,and is suitable for NIR micro-spectrometers applications.