Piezoresistive Cantilever for Nano-Newton Sensing in Two Dimensions

This paper describes a novel two dimensional piezoresistive cantilever force sensor that is used to evaluate the impact force between micro-handling tools and microparticles in the nano-Newton range. Piezoresistor sensors are made from 500 nm-thick p-doped epitaxial silicon on a single crystal silicon substrate. The silicon cantilever is fabricated using bulk micromachining. Switching from the lateral mode to the vertical mode to monitor the lateral and vertical applied force is easily done by using two electronic switches. Force sensitivity of the implemented sensors up to 135 and 310 V/N for lateral and vertical configurations, respectively, is measured. The force resolution is estimated at 5 nN.