Electrothermal Monte Carlo Simulation of GaN HEMTs Including Electron–Electron Interactions

A Monte Carlo device simulator was developed to investigate the electronic transport properties in AlGaN/GaN high-electron mobility transistors (HEMTs). Electron-electron interactions were included using a particle-particle-particle-mesh coupling scheme. Quantum corrections were applied to the heterointerface using the effective potential approach due to Ferry. Thermal effects were also included by coupling the particle-based device simulator self-consistently with an energy balance solver for the acoustic and optical phonons. The electrothermal device simulator was used to observe the temperature profiles across the device. Hot spots or regions of higher temperatures were found along the channel in the gate-drain spacing. Results from electrothermal simulations show self-heating degradation of performance at high source-drain bias. More importantly, the observed nonequilibrium phonon effects may play an important role in determining the thermal distribution in these HEMTs, resulting in reliability issues such as current collapse.