Backward deviation and depth recovery of load-displacement curves of amorphous SiC film under repeating nanoindentation

The deformation and delamination behaviors of sputtered amorphous SiC film have been studied from the load-displacement curves under repeated nanoindentation loading. When the penetration depth is either much larger or much smaller than the film thickness, the curve progresses in forward direction that represents the deformation of the substrate or film. On the other hand, when the penetration depth is comparable with the film thickness, large backward deviation and depth recovery around the minimum load are observed. Observation of the indents by an atomic force microscope proved that delamination starts from the portions beneath the indenter and progresses towards the shoulder of the indent. This behavior is strongly connected with the existing large residual compressive stress in the film. The difference in the delamination behaviors between SiC and TiN, AlN films is also discussed