Analytical model of stress relaxation in 3C-SiC layers on silicon

In this work we analyze the static behavior of cantilevers elaborated on the basis of 3C-SiC thin films grown by chemical vapor deposition on (100) and (111) oriented silicon substrates. A direct microscope observation of cantilever bending indicates the opposite sign of stress gradient (respectively negative and positive) for both film orientations. The correlation of this observation with the commonly admitted nature of intrinsic stress for each orientation (respectively compressive and tensile) leads us to an unexpected conclusion: instead of relaxing, the absolute value of the intrinsic stress increases from the interface to the layer surface. We propose an analytical model that could explain this phenomenon.