Transistors Based on Novel 2-D Monolayer Semiconductors Bi₂O₂Se, InSe, and MoSi₂N₄ for Enhanced Logic Density Scaling

Making ultra-short gate-length transistors significantly contributes to scaling the contacted gate pitch. This, in turn, plays a vital role in achieving smaller standard logic cells for enhanced logic density scaling. As we push the boundaries of miniaturization, it is intriguing to consider that the ultimate limit of contacted gate pitch could be reached with remarkable 1 nm gate-length transistors. Here, we identify InSe, Bi2O2Se, and MoSi2N4 as potential 2-D semiconductors for 1 nm transistors with low contact resistance and outstanding interface properties. We employ a fully self-consistent ballistic quantum transport model starting from first-principle calculations. Our simulations show that the interplay between electrostatics and quantum tunneling influences the performance of these devices over the device design space. MoSi2N4 channels have the best immunity to quantum tunneling, and Bi2O2Se channel devices have the best electrostatics. We show that for a channel length of 12 nm, all the devices can deliver ${I}_{\text {on}}/{I}_{\text {off}} \gt {10}^{{3}}$ , suitable for electronic applications, and Bi2O2Se is the best-performing channel material.