Adhesion Evaluation of an Embedded SiN/GaAs Interface Using a Novel “Push-Out” Technique

Adhesion assessments of an embedded interface in a multilayer system that contains a ductile layer are challenging. The occurrence of plastic deformation in the ductile layer often leads to additional complexity in analysis. In this study, an innovative “push-out” technique was devised to evaluate the interfacial toughness (Gin) of the embedded SiN/GaAs interface in a Au/SiN/GaAs multilayer system. Focus ion beam (FIB) milling was utilized to manufacture the miniaturized specimen and scratching with a conical indenter was used to apply load. This approach effectively minimized plastic deformation in the soft Au layer while inducing tensile stress to the embedded SiN/GaAs interface. As a result, the Au/SiN bilayer detached from the GaAs substrate with little plasticity. The energy associated with the interfacial delamination was derived from analyzing the load–displacement curves obtained from the scratching test. The Gin of the SiN/GaAs interface was calculated by means of energy analysis, and the average Gin was 4.86 ± 0.96 J m−2.