Atomic Force Microscopy Cantilevers for Sensitive Lateral Force Detection

In order to enhance the lateral force sensitivity of atomic force microscopy (AFM) to detect atomic or molecular scale interaction, two types of force sensors were fabricated by additional processing of commercial sensors with the help of focused ion beam (FIB) technology. In one type of cantilever, a hinge was fabricated in the middle of the commercial cantilever by FIB milling, resulting in the reduction of the lateral force constant from 1204 N/m to 118 N/m. For further enhancement of the lateral sensitivity without causing snap-in behavior, a novel force sensor was designed and fabricated through a combination of FIB milling and FIB deposition techniques. The lateral force constant was reduced, for example, from 3600 N/m to 20 N/m, and the measured lateral force resolution attained the order of 1 nN.