© 2021 Elsevier LtdIn recent years, the world has witnessed a huge technological revolution in terms of manufacturing electronic devices and reducing their size, which has reached nanoscale. Metal Oxide Semiconductor Field Effect Transistor (MOSFET) is one of these devices. However, with its downsizing, it affects the efficiency of its associated devices due to the generated heat. In this paper, two-dimensional heat transfer inside a Silicon on Insulator (SOI) MOSFET and traditional MOS transistor is investigated using the Lattice Boltzmann Method (LBM) . It was found that the temperature reaches 340 K and 332 K for SOI-MOSFET and MOSFET at a Knudsen number (Kn=Λ/Lc) of 10, respectively, while the heat flux reaches 21.5 × 1011 W/m2 for SOI transistor and 18.7 × 1011 W/m2for MOS device. The insulating layer (SiO2)in the SOI transistor restrains heat release in the channel region. So, the conventional MOSFET at Kn =10 is thermally more stable, compared to SOI-MOSFET.