Re-Thinking Electronic Circuit Design Through Emerging Reconfigurable Field Effect Transistors

Reconfigurable field-effect transistors, short RFETs, are a unique class of emerging electronic devices that merge n-type, p-type, and ambipolar operation modes into a single element. Unlike conventional MOSFETs, the dominant carrier type in RFETs is purely defined by electrostatics and can be dynamically changed at runtime. This enables new design possibilities by enabling post-fabrication functionality definition, thereby increasing circuit density and adaptability without requiring additional feature-size scaling. However, the added value of the devices requires a reassessment of classical design paradigms to unlock their full potential. This paper aims to provide a comprehensive review of the state of the art in RFET circuit design. Starting from the underlying device physics and material systems, such as group-IV and two-dimensional (2D) materials, the manifold circuit design possibilities in digital, analog, and post-Shannon computing are introduced. We highlight how RFETs aim to enable simplified, energy-efficient, and reusable hardware for edge computing, hardware security, bio-sensing, and cryogenic electronics. Thereby, device- and circuit-level results are exemplified by measurements of transistors fabricated in an industrial 22 nm FDSOI technology. The paper also provides an overview of future key challenges in reliability, BEOL integration, and electronic design automation, offering an outlook on the path towards scalable, sustainable reconfigurable electronics.