Design And Process Research Of Piezoresistive Pressure Sensor Based On Ultra Shallow Junction Doping

Pressure testing is an essential means to guarantee industrial production and support scientific research.Pressure sensors have been widely used in human daily life and scientific exploration activities.For example,in the long-term observation of ocean temperature,salinity,and depth data monitoring,obtain the underwater pressure parameters accurately and sensitively are vital keys for marine scientific research.In addition,the ocean is also a large and complex environmental ecosystem.When scientific instruments work under the sea,they often experience various harsh environments such as shock,vibration,and temperature changes between high and low temperatures.Therefore,developing a pressure sensor with high sensitivity and high reliability has important practical significance and scientific research value.In this thesis,a silicon-based MEMS（Micro-Electro-Mechanical System）piezoresistive pressure sensor is proposed to meet the high sensitivity and high-reliability requirements of the ocean depth data observation instrument.The sensor adopts the classic C-type structure,and uses the piezoresistor at the nanometer scale to amplify the size effect,so as to improve the response of the sensitive unit to the stress and enhance the sensitivity.At the same time,based on the small deflection theory and finite element analysis method,this thesis proposes a design method for the structural parameters of a universal piezoresistive pressure sensor.And the optimal chip structural parameters under the target range is determined by the method.additionally,piezoresistive pressure sensor chip is fabricated successfully by using ion implantation,deep silicon etching,and other semiconductor processes,as well as ultra-shallow junction doping is achieved by Si O₂ layer growth and removal technology;Then the basic performance test of the prepared sensor chip is carried out,and the sensitivity,linearity,hysteresis,repeatability,and other technical indicators of the sensor are calculated.The test results show that at 20 Celsius,the full-scale span（FSS）of the sensor reaches 368.71m V,the sensitivity reaches 0.921m V/10KPa,the resolution accuracy is better than 0.5%,and the nonlinear error is 0.87%,verifying the effectiveness of the design method.Additionally,a series of complex dynamic environment test experiments are carried out on it,including temperature change test,vibration test,and high acceleration shock test.The experimental results show that the sensor has high stability and reliability,which means the sensor is expected to be applied to ocean depth data observation.