Design and fabrication of a novel MEMS device for high resolution force and displacement measurement

We present the design and fabrication of a MEMS device for high resolution force and displacement measurements. Both quantitative and qualitative measurements can be performed in-situ in scanning, transmission and tunneling electron microcopy (SEM, TEM and STM), where the small chamber size makes it challenging to integrate conventional force-displacement sensors. The device exploits the amplification of displacement and attenuation of structural stiffness due to buckling of slender silicon beams to obtain pico-Newton force and nanometer displacement resolution. The design uses buckling of two sets of beams of slightly different lengths to create a loading device. The amplification of the specimen deformation into the micron range enables measurement by visual inspection (optical microscope) without using complex displacement sensing mechanism. Cofabrication of the specimen with the device is possible, thus eliminating the problems associated with alignment and positioning. The device can be used for characterization of materials such as carbon nanotube-polymer interfaces, nanoscale thin films and mechanical testing of single biological cells.