Deciphering Vacancy Defect Evolution of 2D MoS₂ for Reliable Transistors

Abstract

Two-dimensional (2D) MoS2 is an excellent candidate channel material for next-generation integrated circuit (IC) transistors. However, the reliability of MoS2 is of great concern due to the serious threat of vacancy defects, such as sulfur vacancies (VS). Evaluating the impact of vacancy defects on the service reliability of MoS2 transistors is crucial, but it has always been limited by the difficulty in systematically tracking and analyzing the changes and effects of vacancy defects in the service environment. Here, a simulated initiator is established for deciphering the evolution of vacancy defects in MoS2 and their influence on the reliability of transistors. The results indicate that VS below 1.3% are isolated by slow enrichment during initiation. Over 1.3% of VS tend to enrich in pairs and over 3.5% of the enriched VS easily evolve into nanopores. The enriched VS with electron doping in the channel cause the threshold voltage (Vth) negative drift approaching 6 V, while the expanded nanopores initiate the Vth roll-off and punch-through of transistors. Finally, sulfur steam deposition has been proposed to constrain VS enrichment, and reliable MoS2 transistors are constructed. Our research provides a new method for deciphering and identifying the impact of defects.

Nanoporous MoS2 Field-Effect Transistor Based Artificial Olfaction: Achieving Enhanced Volatile Organic Compound Detection Inspired by the Drosophila Olfactory System

“…After the nanopores were precisely immersed in diluted potassium ferricyanide, the shape of the nanopores was transformed from circular to hexagonal. The anisotropic wet etching only affects the exposed area beneath the nanomask, thus preventing the formation of additional defects on the covered surface of the multilayered MoS 2 during wet etching. − Finally, the removal of the BCP mask leaves behind hexagonal nanopores in MoS 2 . The fabrication process of hexagonal nanopores is depicted schematically in Figure a, and the conversion of circular to hexagonal nanopores by precise control of dipping time is shown using scanning electron microscopy (SEM) micrographs in Figure S1.…”

A comparative study on the linear scaling relations for the diffusion of S-vacancies on MoS2 and WS2

“…31 Such a process involves a change of the lattice structure and is, for now, not included in our (grid-based) kMC model. Another experimental study exposing MoS 2 to oxidants like H 2 O 2 has shown that the S-vacancies on the top and the bottom side of a MoS 2 monolayer tend to gather together to form holes in the material, which eventually evolve into nano-pores in the monolayer, 32 a process related to the sublimation of MoS 2 mentioned above. 30 This shows that for a more realistic model, one may need to consider S-vacancies on both sides of a TMDC monolayer and address the scenario when only vacancy sites surround a metal center.…”

Recent progress on ambipolar 2D semiconductors in emergent reconfigurable electronics and optoelectronics

“…(iii) Vertical assembling of 2D materials may be a valuable way for further study and applications, which are promising to transcend the chip size limits. [162,163] Vertical heterostructures formed by multiple stacking via van der Waals integration, provide a method for three-dimensional integration of 2D materials at both the device and circuit levels. [164] Due to their extremely thin thickness, 2D vertical heterostructures provide a short diffusion distance for charge carriers.…”