Elcetrothermomechanical Researc Of Matal Microcontacts In Mems Switch

MEMS switch is widely used in the commercial regime and defense regime.As a result, lots of high frequency wireless communication problems is solved. Thedevelopment of MEMS switches have a profound impact on the development ofnational economy and communication system. However, its practical application islimited due to its failure mechanism. To improve the reliability of MEMS switch,learning about the contact behavior of two rough surfaces has important theoreticalsignificance and application value.Contact resistance and contact heat are important parameters, in order to obtainhigh performance and reliability of MEMS switch. Now, single asperity contactresistance model and contact heat model of RF MEMS switch are more idealizedand not close to the truth extremely.The research of contact behavior focused onexperimental method. However the experimental method is exposed to manybarriers. For example, it may take many months to fabricate and the method iscostly. Furthermore, it's difficult to understand the complex phenomenon of thecontact interface of two rough surfaces accurately. Therefore, it is necessary to setup rough surface contact resistance model and rough surface contact heat model ofMEMS switch, which is a wide application and more tally with the actual situation.And, it is necessary to find a new method to research multi-physical coupling effectof MEMS switch.Based on single asperity model of contact resistance and contact heat whichused in the transition regime between ballistic and diffusive transport, roughsurfaces contact resistance and contact heat models are obtained, which are underthe full stick contact condition. The parameter k is put forward to make contactresistance model and contact heat model is suitable for different materials anddifferent rough surface roughness.Using simpson integration method to calculate the dimensionless rough surfacecontact force, the contact area, contact resistance and contact heat theory model.Thevariation regulation of contact resistance and contact heat is obtained, which isinfluenced by plasticity index , k-value, dimensionless rough surface contact forceand contact area. The rough surfaces contact resistance and contact heat model wereinvestigated with the experiment and single asperity model of contact resistance andcontact heat. They are more appropriate for realistic application. Single asperitymodel of contact resistance model can be think as a special case of dimensionlessrough surface contact resistance model. Using finite element software ANSYS 12.0, an integrated modelingframe-work that incorporates a 3-D surface roughness representation is set up.Some factors is contained in RF MEMS switch FEM contact model, whichinfluence contact characteristics. For instance, rough surface morphologycharacteristics, material properties, environmental temperature, contact force andcontact voltage. The variation regulation of the real areas of contact, contactresistance and contact heat is obtained, through finite element multi-physicsimulation.Consequently, A new method is provided for RF MEMS switchreliability design.