Simulation On Cryogenic And Total Dose Effects On MEMS Acceleration Sensor

In the general trend of miniaturization of spacecraft,the aerospace applications of MEMS inertial devices are particularly important.At present,the research on the adaptability of the space environment of MEMS inertial devices in my country is obviously lagging behind,and it cannot meet the high reliability and long life requirements of subsequent models.Therefore,it is particularly important to study the space environmental effects of MEMS inertial devices to ensure their long life and high reliability in orbit.Based on the electrostatic MEMS accelerometer,this paper carried out the simulation research work of the extremely low temperature environment and total dose irradiation effect.Through software simulation analysis,the corresponding simulation analysis and discussion of the acceleration sensor under different extreme temperatures and radiation damage conditions were made,and finally the auxiliary experiment Verification summarizes its influence law.Based on COMSOL software,the MEMS acceleration sensor is simulated and modeled,and the linear relationship between displacement and sensing voltage and acceleration under steady state is studied,which is consistent with the theoretical results.And optimize the parameters of the key microstructures-comb teeth and cantilever beam,when the comb tooth gap is 2.0 um,the zero position is the smallest,and the accuracy is the highest at this time.Analyze the modal and dynamic response of the accelerometer,of which the first two modals play a major role.To ensure the linearity of the sensor output,the working frequency of the sensor is calculated to be 0-80921Hz.Finally,based on the polysilicon material,the range analysis of the sensor is performed to determine that the maximum working acceleration must be less than 700 g;the displacement between the glass cover and the mass should be less than 0.95 um to ensure overload protection.Based on COMSOL and TCAD software,the device characteristics of the MEMS acceleration sensor under extremely low temperature environment and total dose irradiation environment were studied.As the temperature decreases,the displacement size increases linearly,and the electric potential does not change under low temperature environment,which is consistent with the experimental results that the capacitance value does not change much and the impedance fluctuation is large.The modal analysis and dynamic characteristics of MEMS sensors have not changed significantly.The modal analysis of MEMS sensor and The dynamic characteristics have not changed significantly.The temperature characteristics of the resonant frequency of the cantilever beam of the acceleration sensor in the extremely low temperature environment are simulated and analyzed.The change of the resonant frequency of the micro cantilever beam in the low temperature environment is caused by the change of the elastic modulus of the material.The characteristic frequency varies with the temperature T Increases and decreases,the relationship between Young's modulus and temperature is approximately expressed by the formula.Based on the simulation analysis under TCAD irradiation environment,it can be seen that the minority carrier concentration increases with the increase of the irradiation dose,and the change of the carrier concentration near the surface will locally change the Young's modulus in the surface area,resulting in the change of the resonance frequency.The dynamic characteristics of the cantilever beam are analyzed.As the Young's modulus decreases,the characteristic frequency decreases,and the distribution is linear.