Non-fading Plasmonic Color Printing on Semicontinuous Metal Films with Protective Atomic Layer Deposition

Cu and Ag precursors that are volatile, reactive, and thermally stable are currently of high interest for their application in atomic layer deposition (ALD) of thin metal films. In pursuit of new precursors for coinage metals namely Cu and Ag, a series of new N-heterocyclic carbene (NHC) based Cu(I) and Ag(I) complexes were synthesized. Modifications in the substitution pattern of diketonate-based anionic backbones led to five monomeric Cu complexes and four closely related Ag complexes with the general formula [M(tBuNHC)(R)] (M = Cu, Ag; tBuNHC = 1,3-di-tert-butyl-imidazolin-2-ylidene; R = diketonate). Thermal analysis indicated that most of the Cu complexes are thermally stable and volatile compared to the more fragile Ag analogs. One of the promising Cu precursors was evaluated for the ALD of nanoparticulate Cu metal films using hydroquinone as the reducing agent at appreciably low deposition temperatures (145–160 °C). This study highlights the considerable impact of the employed ligand sphere on the structural and thermal properties of metal complexes that are relevant for vapor phase processing of thin films.

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A Volatile Dialane Complex from Ring Expansion of an N-Heterocyclic Carbene and Its Use in the Thermal Atomic Layer Deposition of Aluminum Metal Films

Organometallics ◽

10.1021/acs.organomet.9b00774 ◽

2020 ◽

Vol 39 (7) ◽

pp. 1006-1013 ◽

Cited By ~ 1

Author(s):

Kyle J. Blakeney ◽

Philip D. Martin ◽

Charles H. Winter

Keyword(s):

Atomic Layer Deposition ◽

Atomic Layer ◽

Ring Expansion ◽

Metal Films ◽

Aluminum Metal ◽

Layer Deposition

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A Volatile Dialane Complex from Ring-Expansion of an N-Heterocyclic Carbene and its Use in Atomic Layer Deposition of Aluminum Metal Films

10.26434/chemrxiv.7343861 ◽

2018 ◽

Author(s):

Kyle Blakeney ◽

Philip Martin ◽

Charles Winter

Keyword(s):

Atomic Layer Deposition ◽

Photoelectron Spectroscopy ◽

Aluminum Hydride ◽

Atomic Layer ◽

Ring Expansion ◽

Metal Films ◽

X Ray ◽

Aluminum Metal ◽

Layer Deposition ◽

The Impact

Treatment of the stable N-heterocyclic carbene (NHC) 1,3-di-tert-butylimidazolin-2-ylidene with two equivalents of AlH3(NMe3) afforded the structurally unusual ring expanded dialane complex 1 in 72% yield after sublimation. Complex 1 has a distorted norbornane-like C3N2Al2 core with two pseudo-tetrahedral Al dihydride sites. Treatment of 1 with Cp2TiCl2 as a model for metal thin film precursors produced the hydride-bridged Ti(III)-Al heterobimetallic complex 2 in 45% crystalline yield. Complex 1 shows good volatility and thermal stability, subliming at 90-100 °C and 50 mTorr and decomposing in the solid state at ~200 °C. The vapor pressure of 1 is 0.75 Torr at 120 °C. These physical properties are promising for a potential atomic layer deposition (ALD) precursor. Aluminum metal films were deposited by thermal ALD using AlCl3 and 1 as precursors with a growth rate of ~3.5 Å/cycle after 100 cycles within an ALD window between 120-140 °C. The films are crystalline aluminum metal by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis showed aluminum metal with 7.0 at.% C, 3.6 at.% N, and 0.9 at.% Cl impurities. The aluminum metal films had an electrically discontinuous morphology. Conductive aluminum metal films have been deposited under similar conditions using a different aluminum hydride reducing co-reactant, which highlights the impact that small precursor differences can have on film characteristics.

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