Nano-notch modulated fracture behaviors in nanoscale thin films

Abstract

This study presents an efficient methodology to assess fracture behavior in nanoscale multilayers. After fabricating a nano-cantilever specimen of Cu/Si/SiN, a notch with the tip radius of 3 ∼ 15 nm was introduced into the SiN layer. By changing the position of notch tip, the delamination of Cu/SiN or Cu/Si interfaces, and the fracture of SiN layer were obtained by in situ TEM bending experiments, respectively. The fracture strength of interfaces and SiN layer was determined using an exponential cohesive zone model (CZM) and the crack propagation from the notch tip was analyzed by phase field simulation. Finally, a fracture phase diagram related to the typical position parameters of nano-notch is proposed to predicted the fracture behaviors including the delamination of different interfaces and the fracture of monolayer in nanoscale multilayers. This study provides significant insights into the fracture behavior occurred at nanoscale and a simple but efficient methodology to evaluate the fracture strength of any part in nanoscale multilayers.