Design And Research Of Electrostatic Nano Electromechanical Switch

With the development of miniaturization of devices,more and more attention has been paid to microelectromechanical and nanoelectromechanical systems.The electrostatic driven flexible nanoelectromechanical(NEM)switches are widely used in RF systems,microfluidic systems,microenergy systems,digital encryption,and other fields due to their simple structures,with semiconductor planar processing technology,,zero leakage current and low power consumption.However,high voltage demand and low switching life seriously restrict the development of NEM switches.In this thesis,based on Euler-Bernoulli beam theory,the influence of nonlinear factors such as residual stress,intermolecular force and mid-plane tensile effect on NEM switching suction behavior is analyzed,and the governing equation of the beam is simplified by Galerkin method.At the same time,MATLAB is used to calculate the fitting voltage of NEM switch under the action of van der Waals force and edge field,Casimir force and edge field,van der Waals force and middle plane tension,Casimir force and middle plane tension respectively.The results show that the intermolecular force reduces the demand for the suction voltage,while the mid-plane tensile effect is opposite.When using single layer graphene as beam element,the ratio of NEM switch beam length to gap should not exceed 52,otherwise the beam element will collapse due to van der Waals forces.In addition,the effect of NEM switch geometry on switch performance is further considered.By theoretical calculation and COMSOL simulation,the influence of geometric parameters on the characteristics of cantilever and double-clamped bridge NEM switches is investigated.In the plate structure supported by fixed beams,this thesis explores the influence of three kinds of fixed beam structures,namely,one font,several font and meandering snake,on the elastic coefficient of the beam,and introduces square holes to explore the influence of the size and number of holes on the switching characteristics.The results show that the voltage can be reduced by 31.28% when the proportion of perforation is 34.41% in cantilever structure,and 33.63% when the proportion of perforation is 37.67%in bridge structure.Finally,COMSOL is used to simulate the sucking and releasing behavior of the perforated NEM switch.This study provides a good reference for the design,simulation,and manufacture of NEM switch.