This paper presents the results of finite element analysis (FEA) modeling and simulation including thermal-electric-structural multiphysics contact phenomenon for a MEMS thermal-mechanical DC switch. The parametric model can be used for design optimizations.
The switch consists of a SiN cantilever membrane (1μm thick, 100μm wide, 400μm long, 1μm sacrificial gap), a Si substrate, and a serpentine NiCr heater. When a voltage is applied to the heater, heating will cause differential thermal expansion and realize switching. One of the applications of such switches is aimed at realizing a high DC-voltage source by using a cascaded array.
Cantilever tip displacement and temperature, and maximum temperature are calculated. Results show that the switch-on time is much smaller than the thermal equilibrium time. Switch-on time calculations for different heater voltages show that higher voltage provides shorter switch-on time and a slightly higher maximum temperature. Results also show that higher surface thermal conductivity provides shorter thermal time constant, thus faster switching speed.
Devices were fabricated as a switch array. Dynamic motion of the cantilevers was measured using MEMS motion analyzer and laser interference. Devices show very good switching behavior and further experimental testing is under way to validate the modeling and simulation results.
Journal: TechConnect Briefs
Volume: 3, Technical Proceedings of the 2006 NSTI Nanotechnology Conference and Trade Show, Volume 3
Published: May 7, 2006
Pages: 582 - 585
Industry sector: Sensors, MEMS, Electronics
Topics: MEMS & NEMS Devices, Modeling & Applications