Transient non-equilibrium thermal transport in silicon-based FinFET

With the continuous scaling of transistor dimensions, localized high-temperature hotspots induced by self-heating effects have become a critical constraint on device reliability. Thermal dissipation has emerged as a key bottleneck limiting both performance improvement and further miniaturization of semiconductor devices. In particular, the transient thermal effects induced by periodic switching during normal device operation are of great importance, as the underlying non-equilibrium thermal transport processes significantly influence device performance. In this work, a coupled electron–phonon Monte Carlo simulation approach is employed to investigate silicon-based FinFETs, systematically revealing the formation mechanism of hotspots and the associated electron scattering processes. On this basis, the transient non-equilibrium thermal transport of phonons is simulated by solving the Boltzmann transport equation (BTE) using the phonon Monte Carlo (MC) method, with the hotspot profile obtained from Electron-MC simulations serving as the heat source term. By comparing the heat source duration with the phonon transit time across the hotspot region, the transient thermal transport characteristics of phonon non-equilibrium states across different time scales are analyzed. Furthermore, simulations performed at typical wireless communication transistor switching frequencies examine the evolution of temperature, energy, and heat flux during dynamic operation, providing further insight into transient non-equilibrium effects in the device. This study offers valuable references for improving the accuracy of transistor thermal modeling and provides a theoretical foundation for the thermal management design of advanced-node devices. • A coupled electron–phonon Monte Carlo simulation framework is established. • By performing multi-scale simulations that combine TCAD, DFT, and electron-MC methods. • Transient phonon transport is analyzed across multiple time scales. • Strong non-equilibrium phonon behavior is investigated under high-frequency switching (10 GHz). • The energy transfer between optical phonons and acoustic phonons is revealed.