Digital twin modeling of the 3ω method and its variants for thermal property measurement in thin-film structures

With the continuous advancement of power electronic devices toward higher power density and operating frequency, efficient thermal management has become increasingly critical. The thermal properties of semiconductor thin films are key to addressing self-heating issues in such devices. The electrical harmonic (3ω) method is widely used for measuring thin-film thermal properties, but its applications to in situ measurements and anisotropic systems often require complex electrode designs, limiting its versatility. This work presents a digital twin model of the 3ω method and its variants based on electro-thermal coupled finite element simulations and inverse heat conduction analysis, and a virtual lock-in amplifier is uniquely combined to simulate phase sensitive detection and low-pass filtering. The model enables full-process simulation of classical 3ω measurements, in situ evaluation of thermal conductivity and thermal boundary resistance using a three-electrode 3ω–2ω configuration, and anisotropic thermal conductivity measurement of bulk materials through multi-electrode layouts. The digital twin also supports sensitivity analysis, uncertainty quantification, and pre-experimental optimization. Furthermore, an in situ measurement strategy for evaluating anisotropic thermal conductivity in thin films on substrates is proposed based on the simulation framework. This work provides a comprehensive virtual platform to support the design, analysis, and optimization of 3ω-based thermal characterization techniques.