Electrothermal simulations of Si and III-V nanowire field effect transistors: A non-equilibrium Green's function study

Abstract

Electro-thermal simulations in ultrascaled Si and InGaAs nanowire field effect transistors have been carried out. Devices with 2.2 × 2.2 nm2 and 3.6 × 3.6 nm2 cross-sections have been investigated. All the standard phonon scattering mechanisms for Si and InGaAs such as optical, polar optical (only for InGaAs), and acoustic phonon mechanisms have been considered. The Non-Equilibrium Green's Function formalism in concomitance with a renormalised 3D heat equation has been used to investigate the effect of self-heating. In addition, locally resolved electron power dissipation and temperature profiles have been extracted. The simulations showed that the heat dissipated inside the transistor increases as the nanowire cross-section decreases. It is also demonstrated that the commonly assumed Joule-heat dissipation overestimates the power dissipated in the transistors studied. It was found that in comparison with standard scattering simulations, electrothermal simulations caused a 72% and 85% decrease in the current in 2.2 × 2.2 nm2 cross-section Si and InGaAs core NanoWire Field Effect Transistors , respectively, when compared with ballistic simulations. The corresponding decrease for scattering without self-heating was 45% and 70% respectively.