Carbon Nanotube Field-Effect Transistors for Next-Generation Multi-Valued Logic and Mixed-Signal Applications: A Comprehensive Review

As the scaling of conventional silicon-based CMOS technology approaches its fundamental physical limits, the "power wall" and diminishing performance gains have necessitated the exploration of "beyond-CMOS" alternatives.Carbon Nanotube Field-Effect Transistors (CNFETs) have emerged as one of the most promising candidates, offering superior carrier mobility, quasi-ballistic transport, and ideal electrostatic properties.This paper presents a comprehensive review of recent advancements in CNFET-based circuit design, with a specific focus on two key application areas: Multi-Valued Logic (MVL) and high-performance analog systems.We synthesize research on fundamental device-level challenges, including process variability, and map the progression from basic ternary logic gates to complex, multi-trait arithmetic systems.Furthermore, we analyze the performance of CNFETs in sequential, memory, and analog circuits, where they demonstrate orders-ofmagnitude improvements over their CMOS counterparts.The review identifies a critical gap between simulation-based performance claims and the lack of experimental validation.It concludes by outlining future research directions, emphasizing the need for variability-aware design methodologies and experimental verification to realize the full potential of this technology.