Stress focusing for controlled fracture in microelectromechanical systems

This letter describes a strategy for controlling fracture in microelectromechanical systems (MEMSs) based on the control of corner sharpness. Studies of model MEMS structures with round (radius of approximately microns), intermediate, and sharp (< 10 nm) corners demonstrate the effects of corner sharpness on the concentration of applied stress. Finite-element analysis reveals that stress distributions intensify and localize as sharpness increases, and transfer printing experiments demonstrate the influence of stress concentration on breakability. (c) 2007 American Institute of Physics.