Realizing XOR and XNOR Functions Using Tunnel Field-Effect Transistors

Recently, a few compact logic function realizations such as AND, OR, NAND and NOR have been proposed using double-gate tunnel field-effect transistor (DGTFET) with independent gate-control. In this article, using two-dimensional device simulations, we propose to realize the exclusive-OR (XOR) and exclusive-NOR (XNOR) logic functions. To implement an XOR function, a dual-material DGTFET (DM-DGTFET) is used. The structure is designed such that the band-to-band tunneling (BTBT) occurs at the boundary of these dual-material gates, rather than at the source-channel junction. Further, to realize the XNOR function, the gate-source and the gate-drain overlaps are used. The proposed DGTFET-based logic function implementations are able to modulate the current flow as per the required functionality, achieving an ON-state current by OFF-state current (ION/IOFF) ratio of order ~109. Furthermore, it is demonstrated that a CMOS-type XNOR gate can be realized by combining the proposed XNOR and XOR functions in the pull-up and pull-down network, respectively.