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

The electronic properties of monolayer (ML) Ga 2 O 3 and transport properties of ML Ga 2 O 3 -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 Ga 2 O 3 has a quasi-direct band gap of 4.92 eV, and the x - and y -directed electron mobilities are 1210 and 816 cm 2 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 L g = 5 nm, the on-current of ML Ga 2 O 3 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 Ga 2 O 3 MOSFETs can meet the demands of the latest International Technology Roadmap for Semiconductors (ITRS) for HP and low-power (LP) applications until L g is less than 4 and 5 nm, respectively. Through underlap structure and doping optimization strategies, ML Ga 2 O 3 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 Ga 2 O 3 MOSFETs with the recently reported beyond-CMOS devices. Our results indicate that ML Ga 2 O 3 can serve as a promising channel material in the post-silicon era.