Research Of New Piezoresistive Sensor

Piezoresistive silicon micro-accelerometer has fast response,high sensitivity,high precision and could be miniaturized easily,especially it is in good low frequency response and can work under strong radiation.In recent years,it develops rapidly,and has a broad application prospects in industrial automatic control,automotive,seismic surveys,military and space systems,medical and biological engineering and other fields.In practical engineering applications,it often requires both high sensitivity and wide appropriciate range,so it is essential to design a piezoresistive sensor with static electricity automatic adjustment range,which could ensure the natural frequency and expand the range of accelerometer.This thesis uses static electricity to achieve the expanded range,and gives a basis to expanding range for both range and sensitivity.Control link of adjustment circuit uses SCM to complete the real-time control of electrostatic drive voltage.This paper describes the current situation of silicon micro-accelerometer, piezoresistive effect of semiconductor, manufacturing process of strain resistance, and studies effects on sensitivity from cantilevel beam length,thickness,strain resistance,and mechanical characteristics.When the acceleration range is large,fixed range prevents measuring range.Therefore,the introduction of static electricity helps to expand the range.This paper designed an electrostatic measurement feedback system circuit, got the table of relationship between logic level and the acceleration direction,summarized the temperature characteristics of the piezoresistive accelerometer,gave the compensation measures,chose the modules,and made the related theoretical analysis. This article discusses the production process of MEMS device and existing packaging technology,and analyzes the beam processing technology,laids the foundation for development of the micro-accelerometer and processing.This design proposal uses the ANSYS software to simulate the membrane-bound cantilever beam. The paper finished the systems analysis, research and design of the structure,sensitivity,range. This article designs a new membrane-bound structure of beam and parameters. The conclusion and results are:cantilever length increases, natural frequency lower, beam thickness increases, natural frequency increases, sensitivity increases.Even in the large acceleration loads, deformation of the cantilever with the introduction of static electricity will not cause failure of the mechanical stiffness.Therefore, to determine the thickness of the beam is reference factors to improve performance on the basis of optimization goals. Optimized measurement range can be achieved up to 600g, and resolution up to 0.001g.