Heterojunction Vertical Band-to-Band Tunneling Transistors for Steep Subthreshold Swing and High on Current

We propose a heterojunction vertical tunneling field-effect transistor and show using self-consistent ballistic quantum transport simulations that it can provide very steep subthreshold swings and high on current, thereby improving the scalability of TFETs for high performance. The turn-on in the pocket region of the device is dictated by the modulation of heterojunction barrier height. The steepness of turn-on is increased because of simultaneous onset of tunneling in the pocket and the region underneath and also due to the contribution of vertical tunneling in the pocket to the current. These factors can be engineered by tuning heterojunction band offsets.