Research On High Precision Vacuum Microelectronic Accelerometer And Interface Circuit

Micro-accelerometers,especially those based on microelectromechanical systems(MEMS),are widely used in core fields such as automotive safety,navigation systems,aerospace,military,and space microgravity.At present,high-precision miniature acceleration sensors have been the focus of research in recent years.Therefore,research on acceleration sensors based on easy integration,anti-interference,and high detection accuracy has important theoretical significance and demand background.In this paper,a novel,high-precision,vacuum microelectronic accelerometer is put forward,based on the theory of field emission;the accelerometer consists of a sensitive structure and an interface.The sensitive structure has a cathode cone tip array,a folded beam,an emitter electrode,and a feedback electrode.The sensor is fabricated on a double-sided polished(1 0 0)N-type silicon wafer;the tip array of the cathode is shaped by wetetching with HNA(HNO3,HF,and CH3COOH)and metalized by Ti W/Au thin film.The structure of the sensor is finally released by the ICP(inductively coupled plasma)process.The anode and feedback electrode are fabricated on the glass substrate,and the whole package of the device is realized by bonding process To achieve closed-loop control and signal detection,the interface circuit was designed.The accelerometer was tested through a static field rollover test,and the test results show that the vacuum microelectronic accelerometer has good performance,with a sensitivity of 3.081 V/g,the non-linearity is 0.84%in the measuring range of-1 g?1 g,The operating bandwidth is120Hz,the average noise spectrum density value is 36.7?V/Hz^1/2,the resolution of the vacuum microelectronic accelerometer can reach 1.1×10^-5g,and the zero stability reaches0.18 mg in 24 h.The main work is listed as follows:(1)The structure and characteristics of various silicon micro-acceleration sensors were analyzed,and the research direction and content of the paper were determined according to the shortage of the existing vacuum micro-electronic acceleration sensors.(2)The structure and working principle of the vacuum microelectronic acceleration sensor were analyzed,and the metal field emission and structural mechanics analysis were further studied.(3)Based on the index requirements of accelerometer,the theoretical model of cathode cone tip was given,the mass block and elastic beam structure with cone tip array were optimized,the finite element analysis(static analysis and modal analysis,etc.)was carried out,and the process flow of cone tip array consistency was explored.(4)The vacuum microelectronic acceleration sensor control and detection interface circuit were designed to realize the closed-loop control of the acceleration sensor and improve the detection accuracy,linearity and stability of the accelerometer.(5)After the prototype was packaged,the test method of the vacuum microelectronic accelerometer was studied and the testing platform was built to accomplish the evaluation of the parameters.