Effect of residual stress on the fracture strength of columnar TiN films

Abstract

The intercolumnar fracture strength of a columnar TiN film was deconvoluted by nanoindentation load-displacement curves. The columnar boundary strength of such films strongly depends on the amount of residual stress present in the film. The residual stress of the coating was modified by plastically stretching the substrate. Indentation studies on the columnar TiN coating as a function of residual stress reveals that the column sliding stress diminishes with residual stress, suggesting that the presence of a high compressive stress substantially improves the fracture strength of a columnar TiN film. True film hardness on the other hand does not change.