COMPARISON OF PROFILE FUNCTIONS FOR THE ESTIMATION OF THE FILM HARDNESS FROM COMPOUND HARDNESS MEASUREMENTS BY A DEPTH-SENSITIVE METHOD

Depth-sensitive hardness measurements are shown for TIN films sputtere d on substrates of different kind, which are softer as well as harder than the film. All substrates show a depth dependence of the hardness, the so-called indentation size effect (ISE), where the hardness decre ases with the penetration depth. The ISE overlaps the depth dependence of the hardness for the compound film-substrate. The course of the de pth dependence of the compound hardness is described by three models: Two variants of the partial volume model (PVM) originating in the plas tic deformation of the film and the substrate, respectively, and the m odel-free phenomenological description of an arc-tangent function (ATF ). All methods give a good fitting in the range of relatively high ind entation depths, where substrate hardness can be assumed as an approxi mately constant value. Additionally it is possible by ATF to describe the depth dependence of the hardness also for low indentation depths, where a strong ISE exists.