Effect of Gate Oxide and Back Oxide Materials on Self-Heating Effect in FinFET

The self-heating effect on the fin field effect transistor (FinFET) is investigated. The dependence of the lattice temperature in the channel center of the transistor on the thickness of the gate oxide, as well as the back oxide, is simulated. Different types of the most used oxide materials (SiO2, HfO2, and Si3N4) and their combination, SiO2+Si3N4, are considered for gate and back oxides. 3D simulation is performed using Sentaurus TCAD. It is shown that the lattice temperature slowly and monotonically decreases with increasing gate oxide thickness. However, the lattice temperature is monotonically increasing with the thickness of the back oxide. This behavior of the lattice temperature depends on the relation between heat generation and dissipation rates in the transistor channel. A difference in the heat conductivity of the oxide materials explains the obtained behavior of the lattice temperature. Also, the lattice temperature dependence on the gate oxide thickness is explained by the increase in the contact area between the gate oxide and the gate with increasing gate oxide thickness. Besides this, it is accounted that the Joule heat generation rate depends on the drain current, which also depends on the oxide materials.