Electrothermal Characterization of Doped Si Heated Microcantilevers Under Periodic Heating Operation

Abstract

This paper reports the frequencydependent electrothermal behaviors of a freestanding dopedsilicon heated microcantilever probe operating under periodic (ac) Joule heating. We conducted a frequencydomain finiteelement analysis (FEA) and compared the steady periodic solution with 3د‰ experiment results. The computed thermal transfer function of the cantilever accurately predicts the ac electrothermal behaviors over a full spectrum of operational frequencies, which could not be accomplished with the 1D approximation. In addition, the thermal transfer functions of the cantilever in vacuum and in air were compared, through which the frequencydependent heat transfer coefficient of the air was quantified. With the developed FEA model, design parameters of the cantilever (i.e., the size and the constriction width of the cantilever heater) and their effects on the ac electrothermal behaviors were carefully investigated. Although this work focused on dopedSi heated microcantilever probes, the developed FEA model can be applied for the ac electrothermal analysis of general microelectromechanical systems.