TY - JOUR
T1 - Volatile Hexavalent Oxo-amidinate Complexes
T2 - Molybdenum and Tungsten Precursors for Atomic Layer Deposition
AU - Mouat, Aidan R.
AU - Mane, Anil U.
AU - Elam, Jeffrey W.
AU - Delferro, Massimiliano
AU - Marks, Tobin J.
AU - Stair, Peter C.
N1 - Funding Information:
The NUANCE Center is supported by the MRSEC program (NSF DMR- 1121262) at the Materials Research Center, the Keck Foundation, the International Institute for Nanotechnology (IIN), the State of Illinois, through the IIN, and Northwestern University. The J. B. Cohen X-ray diffraction facility is supported by the MRSEC program of the National Science Foundation (Grant DMR-1121262) at the Materials Research Center of Northwestern University. Purchase of the NMR instrumentation at the Integrated Molecular Structure Education and Research Center (IMSERC) at Northwestern was supported by the National Science Foundation (Grant CHE- 1048773).
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/3/22
Y1 - 2016/3/22
N2 - New complexes MoO2(tBuAMD)2 (1) and WO2(tBuAMD)2 (2) (AMD = acetamidinato) are synthesized and fully characterized as precursors for atomic layer deposition (ALD). They contain metal-oxo functionalities not previously utilized in ALD-type growth processes and are fully characterized by 1H and 13C NMR, X-ray diffraction (XRD), Fourier transform infrared, thermogravimetric analysis, single-crystal XRD, and elemental analysis. Guided by quartz-crystal microbalance studies, ALD growth methodologies for both complexes have been developed. Remarkably, these isostructural compounds exhibit dramatic differences in ALD properties. Using 1 and O3, amorphous, ultrathin molybdenum oxynitride (MoON) films are grown on Si(100) wafers. Using 2 and H2O yields amorphous WO3 films on Si(100) wafers that crystallize as WO3 nanowires upon annealing. Although 1/H2O and 2/O3 growth was attempted, effective ALD growth could only be obtained with 1/O3 and 2/H2O, underscoring reactivity differences in these precursors. Film thicknesses, compositions, and optical and electrical parameters are characterized by variable angle spectroscopic ellipsometry, X-ray reflectivity, grazing incidence X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and atomic force microscopy techniques. The hitherto unknown ALD chemistry of group VI metal-oxo compounds lays a foundation for their use in the ALD synthesis of heterogeneous catalysts.
AB - New complexes MoO2(tBuAMD)2 (1) and WO2(tBuAMD)2 (2) (AMD = acetamidinato) are synthesized and fully characterized as precursors for atomic layer deposition (ALD). They contain metal-oxo functionalities not previously utilized in ALD-type growth processes and are fully characterized by 1H and 13C NMR, X-ray diffraction (XRD), Fourier transform infrared, thermogravimetric analysis, single-crystal XRD, and elemental analysis. Guided by quartz-crystal microbalance studies, ALD growth methodologies for both complexes have been developed. Remarkably, these isostructural compounds exhibit dramatic differences in ALD properties. Using 1 and O3, amorphous, ultrathin molybdenum oxynitride (MoON) films are grown on Si(100) wafers. Using 2 and H2O yields amorphous WO3 films on Si(100) wafers that crystallize as WO3 nanowires upon annealing. Although 1/H2O and 2/O3 growth was attempted, effective ALD growth could only be obtained with 1/O3 and 2/H2O, underscoring reactivity differences in these precursors. Film thicknesses, compositions, and optical and electrical parameters are characterized by variable angle spectroscopic ellipsometry, X-ray reflectivity, grazing incidence X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and atomic force microscopy techniques. The hitherto unknown ALD chemistry of group VI metal-oxo compounds lays a foundation for their use in the ALD synthesis of heterogeneous catalysts.
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U2 - 10.1021/acs.chemmater.6b00248
DO - 10.1021/acs.chemmater.6b00248
M3 - Article
AN - SCOPUS:84962069196
VL - 28
SP - 1907
EP - 1919
JO - Chemistry of Materials
JF - Chemistry of Materials
SN - 0897-4756
IS - 6
ER -