Interfacial adhesion assessment of SiN/GaAs film/substrate system using microcantilever bending technique

Abstract

In this study, a microcantilever bending technique was applied to evaluate the interfacial adhesion of a silicon nitride (SiN) film on a gallium arsenide (GaAs) substrate. Miniaturised cantilevers in micrometre scale were machined on the SiN/GaAs cross-section using focused ion beam milling. Subsequent bending tests was performed on a nanomechanical testing system. Static and cyclic loadings were applied to bend the cantilevers until they fractured. All cantilevers failed at the SiN/GaAs interface. A finite element analysis (FEA) model was used to simulate the deflection of the cantilevers and the stress state at the locus of failure was analysed. Interfacial fracture strength σ in was derived from the FEA model. The mean values of σ in from the static and cyclic loading tests were 0.8 ± 0.2 and 0.5 ± 0.1 GPa, respectively. An energy balance analysis was then used to evaluate an interfacial toughness of G in = 0.18 ± 0.05 J m-2.