Thermal decomposition of tungsten hexacarbonyl: CVD of W‐containing films under Pd codeposition and VUV assistance

Abstract

Experiments on chemical vapor deposition of W(CO)6‐derived films on silicon substrates were carried out at total pressure of 5‐10 Torr within the temperature range of 250‐350 °C; in Ar or H2 flow. Metallic, carbide and oxide phases composed the obtained films. Deposition in presence of hydrogen results in the increase of the metal content in the film. Sublimed palladium hexafluoracetylacetonate Pd(hfa)2 was used for Pd catalytic promotion of the deposition process. Codeposition with Pd(hfa)2 in hydrogen increases W‐metal fraction and oxygen content while the Pd content is up to 10 at.%. Influence of vacuum ultraviolet (VUV) radiation from Xe excimer lamp (λ ∼172 nm) on the quality of the obtained films was investigated. It was found that VUV irradiation can reduce the oxygen‐content in the film while W‐metal fraction slightly increases. In all films, oxygen was in the form of WO3 and carbon was mainly incorporated as a graphite metastable phase. The influence of other chemical additives is discussed. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Growth-Etch Metal–Organic Chemical Vapor Deposition Approach of WS2 Atomic Layers

“…As mentioned above, based on the results summarized in Figures (a–c) and S2, as well as previous reports, ,− ,, there is a high nucleation density when using metal–organic precursors. The W­(CO) 6 is known to thermally decompose at relatively low temperatures, compared to the ones used here and needed for the growth of highly crystalline TMDCs. This implies a very fast metal-precursor decomposition upon its introduction to the preheated reactor.…”

Highly Conductive Tungsten-Doped Tin(IV) Oxide Transparent Electrodes Delivered by Lattice-Strain Control

“…EDS showed the bulk W concentration to be 0, 1, 1.5, 2, and 3 atom % from the precursor solutions containing 0, 0.2, 0.5, 0.7, and 1 mol % of W­(CO) 6 relative to MBTC, indicating a linear increase in W concentration in the SnO 2 films with increasing W­(CO) 6 precursor and therefore operating under a mass transport-limited growth regime (Figure ). − …”

Optimisation of processing conditions during CVD growth of 2D WS2 films from a chloride precursor

“…The greatest advantage with this approach is that gas flow rates can be precisely controlled using mass flow controllers (MFCs), allowing for far greater reproducibility and much greater flexibility in the choice of tungsten precursor [30]. One common example of the latter is tungsten hexacarbonyl, W(CO) 6 , a hexacarbonyl metal precursor that is stable in air, it is a solid at room temperature and decomposes at temperatures between 600 and 900 °C in the presence of H 2 [31][32][33]. Using W(CO) 6 as a precursor Kang et al have reported the growth of continuous monolayer WS 2 films with grain sizes of * 1 lm on 4-inch fused silica substrates that exhibited carrier mobilities of 18 cm 2 /V-s [34].…”