Thermal characterization of bulk and thin film materials using the mirage-method

Abstract
The photothermal laser beam deflection (PTD) is used to measure the thermal properties of bulk solids and thin film materials. A complete theoretical treatment of the mirage-deflection in the case of a 4 layer-model (gas/film/substrate/backing) and a line heating source has been performed. The thermal properties can be obtained by fitting the theoretical expression to the experimental data. The experimental setup is described and experimental results for the thermal diffusivities of bulk solids over a range of 3 decades are presented. The errors caused by an incorrect assignment of fixed parameters in the non-linear least-square-fitting procedure are studied. A sensitivity study for a film-substrate-system is shown.