Increasing drain voltage of low-bandgap tunnel field-effect transistors by drain engineering

Using low-bandgap semiconductors has been definitively designated as a key technique for boosting on-current of tunnel field-effect transistors (TFETs). Based on two-dimensional simulations, this study shows an upper limit of applied drain voltage and then investigates a method of drain design to allow of increasing the drain voltage for enhancing on-current of low-bandgap TFETs without suffering from high ambipolar off-leakage. By designing the drain with a low concentration of 5×10
¹⁷
cm
⁻³
and a sufficient length of 50 nm, the appropriate drain voltage can be further increased 50% of the bandgap voltage (Eg/q) to improve the on-current of InAs TFET approximately 4 times.