Implementation of Boolean Functions Using Tunnel Field-Effect Transistors

Tunnel field-effect transistors (TFETs) are being examined as a possible replacement of MOSFETs for digital applications. However, TFETs have small ON-state current and, typically, exhibit reduced speed compared with conventional MOSFETs. Nevertheless, TFETs have some distinct characteristics that can be exploited for digital applications. In this article, using simulations, we show that a single device, in which two terminals are biased independently, can realize all primary two-input Boolean functions, such as AND, OR, NAND, NOR, XOR, and XNOR. By modifying the architecture of double-gate TFET (DGTFET) slightly and appropriately choosing device parameters, the Boolean functions AND, OR, NAND, NOR, and XNOR can be implemented. In addition, we propose a twin double-gate (TDG) TFET architecture, which can implement the inhibition functions A'B and AB'. By suitably combining the inhibition functions, an XOR functionality can be obtained in a single device. These implementations demonstrate that the unique characteristics of TFET, such as ambipolar conduction and dependence of tunneling on the gate-source/drain overlaps, can be exploited to realize logic functions compactly.