This paper aims at comparing the self-heating effects influence between FinFETs and Junctionless Nanowire Transistors (JNT) based on three-dimensional numerical simulations. The self-heating of JNT made with different materials, Silicon and Silicon Carbide, is also studied. The results show lower impact in JNT compared to FinFETs. Also, the self-heating is lower in silicon devices then silicon carbide.