Method for backtracking the layer thermal conductivities of multilayer thin film structure using coupled Newton Raphson approach and 3-omega approach

Abstract: The thermal conductivity of thin films is commonly estimated using the 3-omega experimental method. When calibrating the test setup, it is customary to use a specimen with a known thermal conductivity for validation. However, when determining the thermal conductivity of samples with unknown values, numerical approximations can provide a means to validate experimental results and ensure the integrity of the setup. A simple analytical or finite element analysis (FEA) method can be used to achieve this. For multilayer systems of unknown layer thermal conductivities, the 3-omega experimental setup only provides information about the overall bulk thermal conductivity of the system. To obtain the individual layer thermal conductivities, a combined experimental and numerical approach can be used. This article presents a novel method for backtracking the layer thermal conductivities of a multilayer thin film structure using a coupled 3-omega experimental and Newton-Raphson numerical approach. The method is validated using high-fidelity data obtained from literature.