Tungsten bis(tert-butylimide) (hydride) (diisopropyldimethylguanidinate) [W(NtBu)2(H){(iPrN)2CNMe2}] was proposed as potential single source precursor for the growth of tungsten nitride thin films by MOCVD. [W(NtBu)2(H){(iPrN)2CNMe2}] was synthesized by substitution of the Cl ligand in [W(NtBu)2(Cl){(iPrN)2CNMe2}] by a hydrido group. [W(NtBu)2(H){(iPrN)2CNMe2}] was characterized by elemental analysis, 1H NMR, 13C NMR, IR, EI-MS and single-crystal XRD. Thermal properties of the complex were studied by TGA/DTA.
[W(NtBu)2(H){(iPrN)2CNMe2}] (and for comparison it analogue with amide group instead of hydride [W(NtBu)2(NMe2){(iPrN)2CNMe2}] ) was tested as MOCVD precursor for the deposition of WNx layers (either as single source precursor (SSP) or with addition of ammonia NH3). The obtained layers were characterized by SEM and XRD, secondary neutron mass spectroscopy was use for depth-profiling the composition. [W(NtBu)2(H){(iPrN)2CNMe2}] was found to be not suitable as SSP precursor for pure WNx filmsm as the obtained films had surprisingly low N levels. When NH3 was used as a co-reactant , the C content decreased significantly and crystalline β-W2N phase was obtained. In the presence of NH3, hydrido precursor [W(NtBu)2(H){(iPrN)2CNMe2}] resulted in higher C contents in the WNx films, compared to amido complex [W(NtBu)2(NMe2){(iPrN)2CNMe2}].[i]
[i] D. Rische, H. Parala, E. Gemel, M. Winter, R.A. Fischer, Chem. Mater. 2006, 18, 25, 6075–6082, « New Tungsten(VI) Guanidinato Complexes: Synthesis, Characterization, and Application in Metal−Organic Chemical Vapor Deposition of Tungsten Nitride Thin Films », https://doi.org/10.1021/cm061999d , https://pubs.acs.org/doi/abs/10.1021/cm061999d