Influence of the metallic absorption layer on the quality of thermal conductivity measurements by the transient thermo-reflectance method
This work investigates numerically the influence of a metallic absorption layer on the laser-based measurements of the thermal conductivity of dielectric (SiO2) and semiconductor (Si) electronic materials. The validity of the approach and the obtained results are assessed by comparison with experimental measurements obtained for gold-covered silicon dioxide samples. The results reveal the presence of behaviors associated with thermally thin and thermally thick absorption layers, depending on the ratio between the thickness of the absorption layer and the heat penetration depth. Optimal performance of the transient thermo-reflectance method was found to exist for thicknesses of metal layers falling between the identified thermally thin and thermally thick layers.
metallic absorption layer transient thermo-reflectance method thermal conductivity of thin-films thermally thick and thermally thin layers responsivity of thermal conductivity measurements