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.