Engineering SnSe Isolated State Steep‐Slope MOSFETs for High‐Performance Applications

Abstract To overcome Boltzmann thermal limitation, the study investigates isolated‐state field‐effect transistors based on armchair SnSe nanoribbons using first‐principles calculations and quantum transport simulations with various edge passivation strategies, particularly fluorine (‐F) passivation. The results show that ‐F passivation enabling sub‐60 mV decade −1 switching behavior. Key parameters including E sub‐Gap , E Gap , and Δ E play a crucial role in device performance improvement. By introducing asymmetric underlap (UL), the design achieves a steep subthreshold swing (SS) of 46 mV decade −1 and an ON‐state current of 502 µA µm −1 . Compared to symmetric UL, asymmetric UL designs enable better device integration and enhanced performance, thereby meeting the scaling requirements for advanced devices. Further performance enhancement is realized through strain engineering: a 2% uniaxial tensile strain reduces the carrier effective mass and improves band alignment, increasing ON‐state current to 644 µA µm −1 . Incorporating a gate‐all‐around FETs further boosts the current to 796 µA µm −1 without strain and up to 1019 µA µm −1 with strain, while maintaining SS below 60 mV decade −1 , satisfying the International Technology Roadmap for Semiconductors requirements for both high‐performance and low‐power devices. The findings provide theoretical guidance for MOSFET‐based devices with both steep SS and enhanced ON‐state currents, contributing to the advancement of electronic technologies.