Atomic layer deposition of two dimensional MoS2 on 150 mm substrates

Low temperature atomic layer deposition (ALD) of monolayer to few layer MoS2 uniformly across 150 mm diameter SiO2/Si and quartz substrates is demonstrated. Purge separated cycles of MoCl5 and H2S precursors are used at reactor temperatures of up to 475 degrees C. Raman scattering studies show clearly the in-plane (E-2g(1)) and out-of-plane (A(1g)) modes of MoS2. The separation of the E-2g(1) and A(1g) peaks is a function of the number of ALD cycles, shifting closer together with fewer layers. Xray photoelectron spectroscopy indicates that stoichiometry is improved by postdeposition annealing in a sulfur ambient. High resolution transmission electron microscopy confirms the atomic spacing of monolayer MoS2 thin films. (C) 2016 American Vacuum Society.