Controlled growth of Cu and CuOx thin films from subvalent copper precursors.

A new Cu(i) precursor, [(COD)Cu(TFB-TFEA)] (COD = 1,5-cyclooctadiene and TFB-TFEA = N-(4,4,4-trifluorobut-1-en-3-on)-6,6,6-trifluoroethylamine) with high volatility and a clean thermal decomposition pattern was tested for thermal and plasma-assisted chemical vapor deposition (CVD). The heteroleptic configuration based on an anionic and a chelating neutral ligand unified both reactivity and sufficient stability resulting in an intrinsic molecular control over the composition of the resulting CVD deposits. The electronic influence of the ligand on the metal site was studied by 1D and 2D NMR spectroscopy, while EI mass spectrometry revealed the ligand elimination cascade. Thermal and plasma CVD experiments demonstrated the suitability of the copper compound for an atom-efficient (high molecule-to-material yield) deposition of copper(0) and copper(i) oxide films that could be converted into crystalline copper(ii) oxide upon heat treatment at 500 °C.

Volatile Rhenium(I) Compounds with Re-N Bonds and Their Conversion into Oriented Rhenium Nitride Films by Magnetic Field-Assisted Vapor Phase Deposition.

New heteroleptic rhenium(I) compounds, [fac-Re(I)(CO)3(L)] (e.g., L= tfb-dmpda, (N,N-(4,4,4-trifluorobut-1-en-3-on)-dimethyl propylene diamine)), containing anionic and neutral ligands act as efficient precursors to grow polycrystalline rhenium nitride (ReN) films by their vapor phase deposition at 600 °C. Deposition of ReN films under an external magnetic field showed an orientation effect with preferred growth of crystallites along ⟨100⟩ direction. Rhenium complexes reported here unify high stability and reactivity in a single molecule through a Janus-type coordination around a Re center, constituted by a chelating tridentate ligand and three carbonyl groups imparting a facial geometry. Single-crystal diffraction analysis confirmed the structural integrity of the new rhenium compounds. The rigidity of molecular framework was validated in solution via 1D and 2D NMR spectroscopy, in the gas phase via mass spectrometry, and in the solid-state by thermogravimetric analysis and differential scanning calorimetry studies. The analytical data showed that pre-existent Re-N bonds in [fac-Re(I)(CO)3(L)] facilitated low-temperature formation of crystalline ReN deposits confirmed by grazing angle X-ray diffraction analysis. The surface chemical composition and the uniformity of microstructure were provided by X-ray photoelectron spectroscopy (XPS) and scanning and transmission electron microscopy (SEM/TEM), respectively.