Sub-5 nm Ultrathin In₂O₃ Transistors for High-Performance and Low-Power Electronic Applications

Ultrathin oxide semiconductors are promising candidates for back-end-of-line (BEOL) compatible transistors and monolithic three-dimensional integration. Experimentally, ultrathin indium oxide (In₂O₃) field-effect transistors (FETs) with thicknesses down to 0.4 nm exhibit an extremely high drain current (10⁴ μA/μm) and transconductance (4000 μS/μm). Here, we employ ab initio quantum transport simulation to investigate the performance limit of sub-5 nm gate length (L_g) ultrathin In₂O₃ FETs. Based on the International Technology Roadmap for Semiconductors (ITRS) criteria for high-performance (HP) devices, the scaling limit of ultrathin In₂O₃ FETs can reach 2 nm in terms of on-state current, delay time, and power dissipation. The wide bandgap nature of ultrathin In₂O₃ (3.0 eV) renders it a suitable candidate for ITRS low-power (LP) electronics with L_g down to 3 nm. Notably, both the HP and LP ultrathin In₂O₃ FETs exhibit superior energy-delay products as compared to those of other common 2D semiconductors such as monolayer MoS₂ and MoTe₂. These findings unveil the potential of ultrathin In₂O₃ in HP and LP nanoelectronic device applications.