Embedded Capacitive Displacement Sensor for Nanopositioning Applications

The scale of nano-sized objects requires very precise position determination. The state-of-the-art manipulators involve accurate nanometer positioning. This paper presents the design, fabrication process, and testing of a capacitance-based displacement sensor. The nanopositioner application required active sensing area dimensions to be hundreds of micrometers, making it necessary to develop sensor electrodes that are a few micrometers in size. The advantages of the sensor presented are its noninvasive method and very low voltage necessary for signal conditioning. Initial results suggest good linearity and sensitivity of 0.001 pF/μm, permitting a reliable displacement resolution on the order of 100 nm.