Finite Element Analysis of the 3 Method for Characterising High Thermal Conductivity Ultra-Thin Film/Substrate System

The 3 method is an attractive technique for measuring the thermal conductivity of materials; but it cannot characterise high thermal conductivity ultra-thin film/substrate systems because of the deep heat penetration depth. Recently, a modified 3 method with a nano-strip was specifically developed for high thermal conductivity thin film systems. This paper aims to evaluate the applicability of this method with the aid of the finite element analysis. To this end, a numerical platform of the modified 3 method was established and applied to a bulk silicon and an AlN thin-film/Si substrate system. The numerical results were compared with the predictions of theoretical models used in the 3 method. The study thus concluded that the modified 3 method is suitable for characterising high thermal conductivity ultra-thin film/substrate systems.