Authors: M.A. Cullinan, R.M. Panas, M.L. Culpepper
Affilation: Massachusetts Institute of Technology, United States
Pages: 302 - 305
Keywords: carbon nanotube, MEMS, force sensor
Nanonewton level, multi-axis force sensing is required for many biology, materials science and nanomanufacturing applications. Unfortunately, these requirements are difficult to achieve given the size, sensitivity and fabrication limitations associated with existing small-scale sensing techniques. Carbon nanotube-based strain sensors have the potential to overcome some of the limitations in small-scale force/displacement sensing technologies due to their small size and high strain sensitivity. In this paper, we will present the design, fabrication, and testing of a multi-axis MEMS force sensor with integrated carbon nanotube based piezoresistive sensors. The force sensor is designed to fit on top of a HexFlex nanopositioner which is used to accurately position the sensor and apply loads to a sample. The force sensor is composed of three coplanar flexures with integrated CNT-based piezoresistors at the base of the flexures. This force sensor design allows the sensor to measure the torques and the normal force on the stage. Overall, this sensor has a force resolution of 5.6 nN and a range up to 84 μN. In this paper, we will show that through proper sensor design and fabrication it is possible to improve the performance of these sensors by several orders of magnitude over current CNT-based sensors.