Integrated force and displacement sensing in active microcantilevers for off-resonance tapping mode atomic force microscopy

Integrated on-chip actuation and sensing in micro-cantilevers for atomic force microscopy (AFM) allows faster scanning speeds, cleaner frequency responses and smaller cantilevers. However, a single integrated sensor suffers from cross-coupling between displacements originating from tip-sample forces and direct actuation. This paper addresses this issue by presenting a novel micro-cantilever with on-chip actuation and integrated dual sensing for AFM with application to off resonance tapping modes in AFM. The proposed system is able to measure tip force and deflection simultaneously. A mathematical model is developed for a rectangular cantilever to describe the system and is validated with finite element analysis.