Nonlinear modeling and characterization of a thermally driven MEMS actuator with a folded spring reference beam

This paper proposes a nonlinear model and reports the current-voltage (I–V) characteristics of a thermally driven V-shaped MEMS actuator with a folded spring (FS) reference beam. The nonlinear lumped element model is developed using circuit elements with temperature-dependent material properties. In addition, it is shown experimentally that the Joule heating occurring across the polysilicon layer is a nonlinear phenomenon. The equivalent resistance of the polysilicon layer is therefore a function of temperature and thus the resulting nonlinear I–V characteristics is obtained. The experimental I–V data are used to find the resistance-voltage data which are then fed into the model. The actuator with the FS is also compared to the actuator without it in terms of the I–V characteristics, power consumption, experimental tip displacement, and simulated temperature.