Nanoindentation was performed to study the interfacial delamination of SiN/GaAs film/substrate structures, and to determine the adhesion properties of the interface. A sequential dual-indentation approach was developed and the tests were carefully designed to induce interfacial delamination, but avoid the occurrence of the film's through-thickness fracture or buckling. A clamped circular plate model was used to approximate the elastic deflection of the detached film and hence the delamination area. The Griffith energy balance was then used to compute the energy release associated with the delamination. The energy release rate, Gin, calculated was found to be independent on the testing conditions, which agrees with the fundamental assumption of the Griffith energy concept.

Nanoindentation was performed on amorphous silicon nitride films of different thicknesses deposited on gallium arsenide (GaAs) (001) substrates using a conical indenter. Both “pop-in” and ‘pop-out’ were observed from the load-displacement curves when the indentation load exceeded a critical value. Pop-in occurring during loading is associated with plane-slip in the GaAs substrate, and pop-out during unloading is attributed to the interfacial delamination between the film and the substrate. Finite element modeling (FEM) was used to analyze the stress evolution during unloading. The FEM results showed that the stress at the interface evolved from compressive to tensile status during the withdrawal of indentation load, and the interfacial debonding was induced at a critical tensile stress, which is consistent with the pop-out observed. A deformation model for interpreting the pop-in and pop-out events is thereby proposed.