Homogeneous Decomposition of Aryl- and Alkylimido Precursors for the Chemical Vapor Deposition of Tungsten Nitride: A Combined Density Functional Theory and Experimental Study.
MOCVD growth of tungsten nitride (WN) and tungsten carbonitride (WNC) thin films has been reported from the complexes CI(CHCN)W(NR) (1: R = Ph; 2: R = Pr; 3: R = CH). To evaluate the role of the imido substituent in film growth, gas-phase homogeneous decomposition of precursor molecules was investig...
| Publicado en: | Journal of the American Chemical Society Vol. 128; no. 42; pp. 13781 - 13789 |
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| Autores principales: | , , , , , |
| Formato: | Artículo |
| Publicado: |
American Chemical Society
10/25/2006
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| Sumario: | MOCVD growth of tungsten nitride (WN) and tungsten carbonitride (WNC) thin films has been reported from the complexes CI(CHCN)W(NR) (1: R = Ph; 2: R = Pr; 3: R = CH). To evaluate the role of the imido substituent in film growth, gas-phase homogeneous decomposition of precursor molecules was investigated using density functional theory (DFT) calculations. Computational results and NMR kinetics of acetonitrile exchange by 2 in solution verified that dissociation of the acetonitrile ligand should be facile for 1–3 in the temperature range used for film growth (>450 °C). A computational search for transition states for cleavage of W-CI bonds in the presence of H carrier gas was consistent with a σ-bond metathesis pathway. Natural bonding orbital (NBO) analysis and bond energy calculations indicated that 1 has a stronger N-C(imido) bond and a slightly weaker W-N bond than 2 and 3, suggesting a greater role for W-N bond cleavage in depositions from 1. These results are consistent with mass spectrometric fragmentation patterns from 1-3 and low nitrogen content in films deposited from 1 as compared to those from 2 and 3. |
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