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.