State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University , Shanghai 200433, China.
ACS Appl Mater Interfaces. 2017 May 31;9(21):18215-18221. doi: 10.1021/acsami.7b03177. Epub 2017 May 16.
Two-dimensional (2D) semiconductors have become promising candidates for nanoelectronics applications due to their unique layered structure and rich physical properties. However, the significant lack of reproducible p-type doping methods that can avoid the instability induced by the widely used charge transfer doping method greatly limits the applications of these semiconductors in complementary metal-oxide-semiconductor (CMOS) integrated digital circuits. This work presents a new scheme to realize stable p-type doping for WS with excellent layer controllability, wafer-level uniformity, and high reproducibility at the same time. The p-type WS was produced by introducing substitutional doping of sulfur with nitrogen atoms during the sulfurization of WON film. Nitrogen atoms acted as acceptors moving the Fermi level of WS toward the valance band. Both experimental and theoretical investigations were designed to study the physical properties of the films fabricated. The WS based field-effect transistors exhibited a well-defined p-type behavior with a large on/off current ratio of ∼10 and a high hole mobility of ∼18.8 cm V s. This opens up a promising method to realize stable p-type doping of 2D materials, which is very attractive for future large-scale 2D CMOS device applications.
二维（2D）半导体由于其独特的层状结构和丰富的物理特性，成为纳米电子学应用的有前途的候选材料。然而，由于广泛使用的电荷转移掺杂方法所引起的不稳定性，能够实现可重现的 p 型掺杂的方法仍然非常缺乏，这极大地限制了这些半导体在互补金属氧化物半导体（CMOS）集成数字电路中的应用。本工作提出了一种新的方案，用于实现 WS 的稳定 p 型掺杂，同时具有出色的层可控性、晶圆级均匀性和高重现性。通过在 WON 薄膜的硫化过程中引入氮原子替代掺杂，制备出 p 型 WS。氮原子作为受主，将 WS 的费米能级推向价带。设计了实验和理论研究来研究所制备薄膜的物理性质。基于 WS 的场效应晶体管表现出良好的 p 型行为，具有约为 10 的大导通/关断电流比和约为 18.8 cm V s 的高空穴迁移率。这为实现二维材料的稳定 p 型掺杂开辟了一条有前途的途径，这对于未来的大规模二维 CMOS 器件应用非常有吸引力。
