Coupled Electro-Thermal Transport Simulations
At the moment we are investigating self-heating effects in novel nanoelectronic device structures like Gate-All-Around Nanowire Field Effect Transistors (GAA NWFET), tunneling FETs and others. To describe self-heating effects we have to couple electron and thermal transport where the electron and phonon population are driven out of equilibrium. Including coupled electro-thermal transport in an atomistic full-band quantum transport framework is physically and computationally very challenging.
Spectral energy currents for a Si GAA NWFET with a gate-length of 5nm, Vgs = 0.45 V and Vds = 0.6 V. Dark red means high current concentrations, light green means no current. (a) The blue line which indicates the conduction band edge as well as the spectral electron energy current flow through the device is shown. The energy loss of the electrons in the drain region causes creation of phonons and therefore self-heating of the device. The creation of phonons can be observed in (b) at around 25nm where the phonon energy currents start to flow towards source and drain edges (color-code indicates the absolute value of the phonon energy-current). Furthermore we can observe the anharmonic decay (indicated by arrows) of the generated high energy optical phonons due to phonon-phonon interaction.