Effect of material parameters on two-dimensional materials based TFETs: An energy-delay perspective

In this paper, we study the impact of material parameters (i.e. effective mass and bandgap) for two-dimensional (2D) material based tunneling FETs (TFETs) on circuit level metrics. We estimate circuit level metrics (i.e delay and energy consumption) of 2D TFETs at different target OFF current (I
_OFF
) for various combination of material parameters. To fulfill a given I
_OFF
requirement for circuit level metrics, we study the the impact of effective mass and bandgap of the material on device level metrics such as sub-threshold slope, and I
_OFF
. It is observed that it is imperative to have a smaller bandgap irrespective of higher effective mass of the material to achieve minimum energy-delay product (EDP) for a given delay or frequency of operation. The challenge with small bandgap materials is to curb ambipolar currents to meet target I
_OFF
which poses a limit on the maximum performance achieved from the small bandgap material TFETs.