Coupled Electro–Thermal Simulation for Self-Heating Effects in Graphene Transistors

The effects of self-heating on graphene transistor characteristics are examined by self-consistently solving the coupled nonequilibrium Green´s function transport equation with the thermal transport equation. The results indicate that the substrate and gate insulator have significant effects on the temperature rise, decrease of on-current, and lowering of transconductance through surface polar phonon scattering, which causes self-heating effects. For graphene transistors with the channel length of a few hundred nanometers, the temperature rise of about 110 K and on-current lowering of about 17% are predicted because of self-heating. This indicates the importance of a coupled electro-thermal simulation for predicting graphene device characteristics and of thermal engineering on device performance. The dependence of the self-heating effects on the transistor channel length and phonon energy are also examined.