Design of Piezoresistive Silicon Cantilevers with Stress Concentration Region (SCR) for Scanning Probe Microscopy (SPM) Applications

This paper describes and evaluates the incorporation of novel Stress Concentration Region (SCR) in silicon based cantilevers to enhance piezoresistive displacement, force, and torque sensitivities. In brief, SCR is a region, on the cantilever, with a thickness smaller than the cantilever thickness and of an appropriate length to localize stress where piezoresistors are implanted. It was found that in order to improve the sensitivity the length, thickness and placement of the SCR on the cantilever have to be optimized. Performing the optimization can result in a 2X, 5X and 3X improvement in the piezoresistive displacement, force and torque sensitivity, respectively. ANSYS, a well-known Finite Element Analysis (FEA) software, was used to analyze and optimize the above stated parameters of the SCR.