Halogen-Induced s-Band Isolation in 2-D InSeX (X = Cl, Br) for Breaking the Boltzmann Limitation in MOSFETs

As the feature size of MOSFETs approaches its physical limit, 2-D materials have emerged as promising candidates for next-generation channel materials. However, the subthreshold swing (SS) limitations caused by Boltzmann tyranny persist, severely restricting their application in ultralow-power circuits. Here, we demonstrated a halogen-induced In-s-band isolation from the deep Se-p energy level in 2-D InSeX (X = Cl, Br), which can effectively filter out the Boltzmann thermal tail and realize ultrasteep-slope SS. Remarkably, the weaker In–Br bonding in InSeBr leads to reduced orbital overlap and a narrower isolated bandwidth, thereby effectively suppressing thermal leakage current. The 2-D InSeBr n-MOSFET achieves an ultrasteep SS of 48 mV/dec, a highon-state current (${I}_{\text {on}}\text {)}$of$3713~\mu $A/$\mu $m, a small delay time ($\tau \text {)}$of 0.041 ps, and a low power-delay product (PDP) of 0.114 fJ/$\mu $m, which can satisfy International Technology Roadmap for Semiconductors (ITRS) requirements. This work reveals the application potential of 2-D InSeX (X = Cl, Br) for future low-power electronics and provides new insights for developing advanced integrated circuit technology.