Chip‐Scale Graphene/IGZO Cold Source FET Array Enabling Sub‐60 mV dec ⁻¹ Super‐Steep Subthreshold Swing

Abstract

Abstract In this study, the first sub‐60 mV dec −1 super‐steep subthreshold swing (SS) of graphene/InGaZnO (IGZO) cold‐source field‐effect transistor (CSFET) arrays is demonstrated. The linear density of states of the Dirac‐cone‐type graphene suppresses the Boltzmann thermal tail near the graphene/IGZO interface which in turn causes super‐exponentially decaying electron density with increasing energy, leading to an extremely low off current and SS value. In particular, by introducing an HfO 2 high‐k dielectric with a low body factor, the surface potential is effectively modulated, further reducing SS by ≈46.4 mV dec −1 . Furthermore, highly uniform sub‐60 mV dec −1 SS with a yield of ≈89.1% is achieved in the IGZO CSFET 8 × 8 array devices, with a record SS value of 23.66 mV dec −1 compared to previously reported oxide‐semiconductor transistors. The proposed IGZO CSFET device is expected to drive significant advancements in high‐speed and ultralow‐power electronic circuits.