Evaluating Pile-Up and Sink-In During Nanoindentation of Thin Films

Abstract

Determining mechanical properties is crucial when selecting materials for thin film applications. Nanoindentation has been used as an experimental method because of its ease in testing small-scale applications, such as thin films. When the film material properties are complicated by substrate effects, more analysis is necessary to capture the correct information using this technology. In this work, we discuss the differences in pile-up when changing film and substrate. We aim to describe these trends quantitatively through material properties. First, we show our model is an improved method to the nanoindentation technique, and is vital in testing films on substrates. Next, we have measured pile-up and sink-in with a technique including scanning electron microscopy images to better understand the effects of these phenomena on material properties. Also, we have examined sink-in similarly based on projected area measurements with an emphasis on yielding properties. These evaluations lead to further information of film properties that were unknown through nanoindentation in previous tests, which in turn is crucial for thin film applications like electronics and coatings.