Wafer‐Scale Synthesis of Reliable High‐Mobility Molybdenum Disulfide Thin Films via Inhibitor‐Utilizing Atomic Layer Deposition

Abstract

A reliable and rapid manufacturing process of molybdenum disulfide (MoS ) with atomic-scale thicknesses remains a fundamental challenge toward its successful incorporation into high-performance nanoelectronics. It is imperative to achieve rapid and scalable production of MoS exhibiting high carrier mobility and excellent on/off current ratios simultaneously. Herein, inhibitor-utilizing atomic layer deposition (iALD) is presented as a novel method to meet these requirements at the wafer scale. The kinetics of the chemisorption of Mo precursors in iALD is governed by the reaction energy and the steric hindrance of inhibitor molecules. By optimizing the inhibition of Mo precursor absorption, the nucleation on the substrate in the initial stage can be spontaneously tailored to produce iALD-MoS thin films with a significantly increased grain size and surface coverage (>620%). Moreover, highly crystalline iALD-MoS thin films, with thicknesses of only a few layers, excellent room temperature mobility (13.9 cm V s ), and on/off ratios (>10 ), employed as the channel material in field effect transistors on 6″ wafers, are successfully prepared.

Morphology-controlled MoS2 by low-temperature atomic layer deposition

“…Atomic layer deposition (ALD), due to its high conformality, shows great potential in the precise control of the thicknesses and morphologies of the deposited layers, especially for the preparation of complex nanostructures. 1,[18][19][20][21][22][23] Based on these peculiarities, several TMD nanomaterials with varying morphologies and complex nanostructures have been synthesized by ALD by modifying various deposition parameters and/or by using different substrates and templates. [24][25][26] For example, Mattinen et al deposited a ∼3 nm thick SnS 2 film on 3D nanoscale trench substrates with a depth of 90 and a width of 30 nm.…”

Electronic Devices and Circuits Based on Wafer‐Scale Polycrystalline Monolayer MoS2 by Chemical Vapor Deposition

“…For liquid exfoliation, although it could guarantee the production of a relatively large quantity of materials, it lacks a good control of the flake size and thickness, and the resulting materials tend to be contaminated with excessive impurity doping . Regarding ALD process, it usually results in low crystallinity of the produced film . Besides, highly uniform MoS 2 monolayer film was produced by a well‐designed MOCVD process, but the use of vapor phase reactants makes the growth process more sophisticate .…”

TFT Channel Materials for Display Applications: From Amorphous Silicon to Transition Metal Dichalcogenides

“…Ad‐layer growth rate on the as‐grown MoS 2 or WS 2 is very low, which results in a strictly monolayer 80a. Using methods based on self‐limiting growth mechanisms (atomic layer deposition or ALD, inhibitor‐utilizing ALD or iALD) yield uniform films regardless of the substrate size (Figure 5e), and up to a 6 inch wafer level growth has been reported 92. Although a suitable method on a lab‐scale, molecular beam epitaxy (MBE) is also possible for the growth of a uniform thin film, which is currently reported up to 2 inches 93…”