Recent Advances on Multivalued Logic Gates: A Materials Perspective

Abstract

The recent advancements in multivalued logic gates represent a rapid paradigm shift in semiconductor technology toward a new era of hyper Moore's law. Particularly, the significant evolution of materials is guiding multivalued logic systems toward a breakthrough gradually, whereby they are transcending the limits of conventional binary logic systems in terms of all the essential figures of merit, i.e., power dissipation, operating speed, circuit complexity, and, of course, the level of the integration. In this review, recent advances in the field of multivalued logic gates based on emerging materials to provide a comprehensive guideline for possible future research directions are reviewed. First, an overview of the design criteria and figures of merit for multivalued logic gates is presented, and then advancements in various emerging nanostructured materials-ranging from 0D quantum dots to multidimensional heterostructures-are summarized and these materials in terms of device design criteria are assessed. The current technological challenges and prospects of multivalued logic devices are also addressed and major research trends are elucidated.

Beyond 10 MHz Organic Electrochemical Transistors for Printed Multi-valued Logic Circuits

“…Owing to the difficulty in realizing complex logic configurations and achieving the desirable response time in OECTs, the required level of the signal processing cannot be achieved for even coarse bioelectronic computing applications such as biointerfacing. Consequently, the application of OECTs to more advanced logic components such as multivalued logic transistors (MVTs) [21][22][23][24] , a key direction of the More-than-Moore era [25] , has not been considered despite the foreseeable synergetic advantages. For example, owing to the limited material selection associated with restricted operating principles such as band-to-band tunneling, it is difficult to realize stable, tunable, and distinctive multistate electrical characteristics in conventional MVT technology.…”

Multi‐State Heterojunction Transistors Based on Field‐Effect Tunneling–Transport Transitions

“…[ 1 ] The generation of multiple information states (three or more) per unit memory device in MVL electronics can not only increase the level of device integration but also fundamentally reduce the circuit complexity, the number of interconnections and components, and, consequently, the power consumption vis‐à‐vis the conventional binary system. [ 1d,e,2 ] This enticing possibility has motivated intensive research on the generation of multiple physical states via the storage of a restricted amount of charge carriers in nanostructures, [ 3 ] quantum dots, [ 4 ] or organic molecules. [ 5 ] Moreover, the generation of multi‐stable logic states using negative differential resistance and negative transconductance devices has also been extensively investigated because of the inherently multistable nature of their current–voltage characteristics.…”

Ternary Devices Based on Partially Aligned MoS2/h‐BN/Graphene Heterostructures

“…In addition to various ternary devices, other devices, such as two-terminal resistive switching devices [35] and optical memory devices based on 2D materials, [36] have been used to generate more than ten logic states. [37] However, despite the rapid progress in the field of MVL, there are few reports to demonstrate integrated circuits consisting of ternary devices or MVL devices due to the limitation of device uniformity and the difficulty in adjusting intermediate states.Herein, we report a ternary device based on a partially aligned MoS 2 -based flash memory device (Figure 1). When a channel of MoS 2 was fully aligned with a floating gate of graphene, large hysteresis with binary states was observed in the transfer curves, as reported by others.…”

“…In addition to various ternary devices, other devices, such as two-terminal resistive switching devices [35] and optical memory devices based on 2D materials, [36] have been used to generate more than ten logic states. [37] However, despite the rapid progress in the field of MVL, there are few reports to demonstrate integrated circuits consisting of ternary devices or MVL devices due to the limitation of device uniformity and the difficulty in adjusting intermediate states.…”