Determination of the Adhesive Strength of Monocrystalline Layers as a Thin Film on a Silicon Substrate by Means of Instrumented Indentation Testing

In this work, an experimental test methodology is developed to investigate the adhesive strength of brittle monocrystalline layers on silicon substrates. The aim is to evaluate the bonding properties during production. The experimental method allows direct measurement of the adhesive strength at wafer level. This overcomes a decisive disadvantage of alternative methods: sample preparation. The use of instrumented indentation testing using wedge tips makes it possible to automate both the test and the evaluation. This makes it suitable for industrial use. Finite element and analytical models are used and compared with each other to calculate the adhesive strength. The validity range of the analytical models is shown by comparing them with the finite element models. In addition, the development of the phase angle, which describes the crack mode components, is illustrated. Investigations are carried out using the layer system of lithium tantalate thin films on a silicon substrate as an example.