Characterization of piezoresistive and electrothermal sensors in MEMS devices

Displacement sensing with nanometer or sub-nanometer resolution is a necessity in numerous microelectromechanical (MEMS) devices. Acquiring a quantitative knowledge about the characteristics of these sensors can help realize MEMS devices with improved performance. Electrothermal and bulk piezoresistive are two sensing mechanisms whose key features, including their bandwidth, resolution and noise level, are compared in this paper. As a test platform, the sensors are implemented in a MEMS nanopositioner. The results indicate that the bulk piezoresistive sensor has a superior performance compared to the electrothermal sensor.