From thin film and coating buckling structures to mechanical properties

Thin films and coatings produced by sputtering methods often develop very high internal stresses, sometimes about few GPa in compression and are then susceptible to delamination and buckling. Although this phenomenon is undesirable for future technological applications, one may take benefit of it for intrinsic mechanical properties characterization of both films and substrates. Most of buckling patterns can be simply understood in the frame of elastic theory, as an optimum release of stresses in the film. In this way, the geometrical analysis of buckling structures can be thought as an easy and interesting method to determine the mechanical properties of the thin films and coatings that can be strongly different from those of bulk crystals. This method was successfully applied to extract the elastic properties of a stainless steel 600 nm thick film deposited on silicon wafers.