Second-generation hexavalent molybdenum oxo-amidinate precursors for atomic layer deposition

Area of Science:

• Inorganic Chemistry
• Materials Science
• Nanotechnology

Background:

• Molybdenum oxo-amidinate complexes are investigated for their potential in materials deposition.
• Existing precursors may have limitations in terms of yield, handling, or film quality.

Purpose of the Study:

• To synthesize and characterize novel molybdenum oxo-amidinate complexes, specifically MoO2(R2AMD)2.
• To evaluate the performance of these complexes as precursors for molybdenum trioxide (MoO3) film growth via atomic layer deposition (ALD).
• To compare the efficacy of the synthesized complexes against existing ALD precursors.

Main Methods:

• Synthesis of molybdenum oxo-amidinate complexes: MoO2(R2AMD)2, where R = cyclohexyl (Cy) and isopropyl (iPr).
• Characterization techniques: Nuclear Magnetic Resonance (NMR) spectroscopy (1H, 13C), X-ray diffraction, and thermogravimetric analysis (TGA).
• ALD performance evaluation: Quartz-crystal microbalance (QCM) and X-ray photoelectron spectroscopy (XPS) studies for MoO3 film growth.

Main Results:

• Two new complexes, MoO2(Cy2AMD)2 (2) and MoO2(iPr2AMD)2 (3), were successfully synthesized and characterized.
• Complex 3 demonstrated improved performance as an ALD precursor for MoO3 compared to the R = t-butyl derivative.
• Complex 3 offers higher yields (>80%), easier handling with no mass loss, and produces nitride-free MoO3 films when used with O3.

Conclusions:

• The synthesized molybdenum oxo-amidinate complexes are viable precursors for MoO3 deposition.
• Complex 3 represents a significant advancement in ALD precursors for high-quality MoO3 film fabrication.
• The improved properties of complex 3 facilitate efficient and reliable growth of pure MoO3 films.