Delamination study of InSb infrared focal plane arrays using a cohesive zone model

Abstract

Local interfacial delamination and cracking, appearing in the top surface of InSb infrared focal plane arrays (IRFPAs), are typical failure patterns observed in liquid nitrogen shock tests. In order to explore the delamination mechanism and cracking process, based on the thought of three-dimensional equivalent modeling, we employ the cohesive zone model (CZM) for the interface where delamination appears most easily, and create the structural model of 128×128 InSb IRFPAs. Simulation results contain all the deformation characteristics appearing in the typical optical fracture photographs. That is, firstly, in the photosensitive element array, the global square checkerboard buckling pattern reappears; secondly, in the negative electrode material, the InSb chip is gradually separated from the negative electrode, and the width of delamination is widened gradually; thirdly, on the periphery of InSb IRFPAs, the surface is flat. All these findings suggest that the model created in this paper is correct, and the parameters selected are suitable. Based on the delamination model, it is possible to find the initiation and propagation rule of cracks in the research that follows.