Modeling self-heating effects in nanoscale SOI devices

We have developed electro-thermal device simulator that at present self-consistently solves the Boltzmann Transport Equation (BTE) for the electrons and the energy balance equations for acoustic and optical phonons. The simulator has been successfully used in investigation of self-heating effects in different technology nodes of nano-scale fully-depleted (FD) silicon on insulator (SOI) devices and dual gate (DG) device structures. Our simulation results suggest that self-heating has less degrading effect on the on-current in smaller devices in which non-stationary transport and velocity overshoot effect dominate the carrier transport. We also find that the choice of the boundary conditions on the gate (Dirichlet vs. Neumann) has significant impact on the current degradation. The role of Neumann and leaky Dirichlet boundary conditions at the source and drain contact is also examined and estimates on the overall current degradation are presented. Finally we illustrate that the use of anisotropic and temperature dependent thermal conductivity is needed to properly determine the temperature of the hot spot which is important parameter regarding device reliability.