Design and Analysis of Nonuniformly Shaped Heaters for Improved MEMS-Based Electrothermal Displacement Sensing

Conventional heaters used in microelectromechanical systems (MEMS) electrothermal displacement sensors typically feature a uniform cross section, which results in a nonuniform temperature profile. In this paper, electrothermal sensors with a shaped beam profile are introduced, with simulation results showing that a much flatter temperature distribution is achieved across the length of the heater. The proposed sensor design is implemented as the displacement sensor for a MEMS nanopositioner together with a more conventional electrothermal sensor design for comparative purposes. Experimental testing indicates that the shaped profile significantly improves upon the conventional sensor design in a number of areas, including sensitivity, linearity, and noise performance.