Nucleation and Growth of Molybdenum Disulfide Grown by Thermal Atomic Layer Deposition on Metal Oxides

Authors

Jake Soares, Boise State University
Steven Letourneau, Boise State University
Matthew Lawson, Boise State University
Anil U. Mane, Argonne National Laboratory
Yu Lu, Boise State UniversityFollow
Yaqiao Wu, Boise State UniversityFollow
Steven M. Hues, Boise State University
Lan Li, Boise State UniversityFollow
Jeffrey W. Elam, Argonne National Laboratory
Elton Graugnard, Boise State UniversityFollow

Document Type

Article

Publication Date

12-2022

Abstract

To enable greater control over thermal atomic layer deposition (ALD) of molybdenum disulfide (MoS₂), here we report studies of the reactions of molybdenum hexafluoride (MoF₆) and hydrogen sulfide (H₂S) with metal oxide substrates from nucleation to few-layer films. In situ quartz crystal microbalance experiments performed at 150, 200, and 250 °C revealed temperature-dependent nucleation behavior of the MoF₆ precursor, which is attributed to variations in surface hydroxyl concentration with temperature. In situ Fourier transform infrared spectroscopy coupled with ex situ x-ray photoelectron spectroscopy (XPS) indicated the presence of molybdenum oxide and molybdenum oxyfluoride species during nucleation. Density functional theory calculations additionally support the formation of these species as well as predicted metal oxide to fluoride conversion. Residual gas analysis revealed reaction by-products, and the combined experimental and computational results provided insights into proposed nucleation surface reactions. With additional ALD cycles, Fourier transform infrared spectroscopy indicated steady film growth after ∼13 cycles at 200 °C. XPS revealed that higher deposition temperatures resulted in a higher fraction of MoS₂ within the films. Deposition temperature was found to play an important role in film morphology with amorphous films obtained at 200 °C and below, while layered films with vertical platelets were observed at 250 °C. These results provide an improved understanding of MoS₂ nucleation, which can guide surface preparation for the deposition of few-layer films and advance MoS2 toward integration into device manufacturing.

Copyright Statement

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in: Soares, J.; Letourneau, S.; Lawson, M.; Mane, A.U.; Lu, Y.; Wu, Y.; Hues, S.M.; Li, L.; Elam, J.W.; and Graugnard, E. (2022). Nucleation and growth of molybdenum disulfide grown by thermal atomic layer deposition on metal oxides. Journal of Vacuum Science & Technology A, 40(6), 062202. https://doi.org/10.1116/6.0002024. and may be found at https://doi.org/10.1116/6.0002024.

Publication Information

Soares, Jake; Letourneau, Steven; Lawson, Matthew; Mane, Anil U.; Lu, Yu; Wu, Yaqiao; Hues, Steven M.; Li, Lan; Elam, Jeffrey W.; and Graugnard, Elton. (2022). "Nucleation and Growth of Molybdenum Disulfide Grown by Thermal Atomic Layer Deposition on Metal Oxides". Journal of Vacuum Science & Technology A, 40(6), 062202. https://doi.org/10.1116/6.0002024