A comparative approach for calibration of the depth measuring system in a nanoindentation instrument

Within the past decade, the nanoindentation method has developed into an indispensable tool of quality assurance enabling determination of the mechanical properties of small volumes of material. For a high quality of the characterisation of these materials the calibration of nanoindentation instruments, particularly their depth measuring system, is necessary. A comparative approach is presented to fulfil the calibration requirement, in which an optical probe interferometer and step height standards are used. In order to improve the measurement uncertainty of the calibration procedure based on step height standards, a simple force modulation technique was introduced. Experimental results indicate that the two calibration methods coincide. Therefore advice on how to choose a suitable calibration method is given.