Research On Thickness Shear Mode In FBAR As A Pressure Sensor

With rapid development of thin film and micro-nano manufacturing technology,thin film bulk acoustic wave resonator(FBAR)has been widely used in the field of communications.Compared with the traditional dielectric resonator and surface acoustic wave(SAW)devices,FBAR has the advantages of small volume,low insertion loss,high working frequency,high quality factor,which is considered to be one of the most promising components of the new generation of wireless communication system and biochemical detection.Thin film bulk acoustic wave resonator has attracted many people's interest because of its excellent characteristics in the field of sensor.By measuring resonance frequency of FBAR,the advantages of measurement results are easy to obtain.In addition,FBAR sensor compatible with integrated circuit technology,integrated sensing module and readout circuit module on the same chip,so as to realize in harsh environments or sensor used in wireless sensor network system.Therefore,the theoretical analysis and basic application research of FBAR sensor has extremely important scientific research value.The main research contents are as follows:(1)The research status of FBAR sensors at home and abroad is summarized in detail.Based on analysis of the existing FBAR pressure sensors,2 kinds of FBAR pressure sensor models are established.In the vibration model,the vibration displacement equation of piezoelectric thin film is calculated,and resonance frequency,electromechanical coupling coefficient and electrical characteristics of FBAR pressure sensor are studied.(2)The finite element model of FBAR pressure sensor is established by using COMSOL Multiphysics multi physical field finite element simulation software.1)According to the characteristics of frequency analysis,to determine the size of piezoelectric thin film,film thickness parameters and electrode size,electrode thickness parameters of FBAR pressure sensor;simulation of deformation displacement distribution and admittance curve of pressure sensor.2)The characteristics of longitudinal wave mode FBAR sensor and shear wave mode FBAR sensor are simulated and analyzed respectively.3)Simulation analysis of lateral shear wave excitation mode of FBAR pressure sensor in different liquid environment in the resonance frequency domain response relationship between voltage,under different pressure conditions on FBAR pressure sensor,the resonance frequency changes gradually,got the sensing sensitivity of FBAR pressure sensor in different liquid phase environment calculation.(3)The preparation process of shear wave mode FBAR pressure sensor was studied.Simulation analysis of structure model has been made based on the mask,and the FBAR pressure sensor air gap type structure using MEMS processing technology.The field emission scanning electron microscope was used to make a quantitative analysis of the FBAR pressure sensor,and a Raman spectrometer was used to detect the components of each layer of the FBAR pressure sensor,and the FBAR pressure sensor is tested and analyzed by network analyzer.