Comparison of atomistic quantum transport and numerical device simulation for carbon nanotube field-effect transistors

Carbon nanotube field-effect transistors (CNTFETs) are studied using atomistic quantum transport simulation and numerical device simulation. The studied CNTFETs consist of n-doped source-and drain-electrodes with an ideal wrap-around gate. Both the off-as well as the on-currents are described in very good agreement by both methods, which verifies the employed simplified approach in the numerical device simulation. The off-current is strongly dependent on interband tunneling in the studied CNTFETs. Thus, the good agreement between the methods verifies the tunneling model in the numerical device simulator, which can therefore be used to describe other tunneling devices, too. On the basis of the two methods we also discuss the effect of different channel lengths and aggressive gate scaling.