Minimizing the uncertainties associated with the measurement of thermal properties by the transient thermo-reflectance method

An approach for optimizing the transient thermo-reflectance (TTR) measurement of thermal properties is presented. The influence of the most important parameters of the system on the accuracy of the TTR measurements is investigated. An overall performance criterion is defined based on the responsivity of a given system and the thermoreflectance coefficient of the sample under test. It is shown that in order to obtain the smallest measurement uncertainty one should use a metallic absorption layer with the highest possible thermoreflectance coefficient and then compute the optimum thickness of that layer by maximizing the responsivity of the TTR system. The responsivity represents the sensitivity of the TTR method to the measurement of the thermal properties of a sample and relates the overall uncertainty of a TTR measurement to the uncertainties associated with the TTR apparatus.