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 (G) 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 G of the SiN/GaAs interface was calculated by means of energy analysis, and the average G was 4.86 ± 0.96 J m^-2.