Modulating interface performance between 2D semiconductor MoSi₂N₄ and its native high-k dielectric Si₃N₄

Abstract

Two-dimensional (2D) transition metal silicon nitrides (MSi2N4: M denotes Mo or W) are promising channel materials for nanoelectronics owing to their attractive structural and electronic properties. The integration of high-κ dielectrics into 2D semiconductors MSi2N4 is one of the vital steps for achieving high-performance electronic devices, which however remains challenging. In this study, we propose silicon nitride (Si3N4) as the native high-κ dielectric for 2D MSi2N4 and reveal their interfacial properties. Using first-principles calculations, we show that a high-performance interface can be formed, as supported by weak interface interaction, insignificant charge density redistribution, and nearly intact electronic properties of monolayer MSi2N4 with the integration of Si3N4. We further demonstrate that interfacial hydrogenation can effectively passivate the dangling bonds at the Si3N4 surface, leading to improved interface performance. Importantly, this interfacial hydrogenation does not bring a detrimental effect to both the high-κ dielectric and the 2D semiconductors, as it is thermodynamically and kinetically stable at the Si3N4 surface. These results provide a deep understanding for the integration of high-κ dielectrics on 2D semiconductors MSi2N4, design a viable interfacial engineering strategy to improve the interface performance, and therefore could be useful for the development of 2D MSi2N4 based high-performance electronics.