First-Principles-Based Quantum Transport Simulations of High-Performance and Low-Power MOSFETs Based on Monolayer Ga2O3

The electronic properties of monolayer (ML) Ga2O3 and transport properties of ML Ga2O3-based n-type metal-oxide-semiconductor field-effect transistors (MOSFETs) are investigated by first-principles calculations under the framework of density functional theory (DFT) coupled with the nonequilibrium Green's function (NEGF) formalism. The results show that ML Ga2O3 has a quasi-direct band gap of 4.92 eV, and the x- and y-directed electron mobilities are 1210 and 816 cm2 V-1 s-1 at 300 K, respectively, under the full consideration of phonon scattering. The electron-phonon scattering mechanism shows a temperature-dependent behavior, with the acoustic modes dominating below 300 K and optical modes dominating above 300 K. At a gate length of Lg = 5 nm, the on-current of ML Ga2O3 n-MOSFET for high-performance (HP) application is 2890 μA/μm, which is more than those of the most reported two-dimensional (2D) materials. The delay time as well as the power delay product of ML Ga2O3 MOSFETs can meet the demands of the latest International Technology Roadmap for Semiconductors (ITRS) for HP and low-power (LP) applications until Lg is less than 4 and 5 nm, respectively. Through underlap structure and doping optimization strategies, ML Ga2O3 n-MOSFET can further fulfill the ITRS requirements for 1 nm. At last, we compare the performance of the 32-bit arithmetic logic unit (ALU) built on ML Ga2O3 MOSFETs with the recently reported beyond-CMOS devices. Our results indicate that ML Ga2O3 can serve as a promising channel material in the post-silicon era.