Magnesium β-ketoiminates as CVD precursors for MgO formation

Area of Science:

• Organometallic Chemistry
• Materials Science
• Chemical Vapor Deposition

Background:

• Bis(ketoiminato)magnesium(ii) complexes offer potential as precursors for materials deposition.
• Understanding the structure-property relationships of these complexes is crucial for optimizing deposition processes.

Purpose of the Study:

• To synthesize and characterize novel bis(ketoiminato)magnesium(ii) complexes.
• To investigate their thermal stability and volatility.
• To evaluate their efficacy as precursors for depositing thin magnesium oxide (MgO) films via Metal-Organic Chemical Vapor Deposition (MOCVD).

Main Methods:

• Synthesis of complexes using magnesium tert-butoxide and ketoiminato ligands.
• Characterization by X-ray diffraction, thermogravimetric analysis (TG), differential scanning calorimetry (DSC), and thermogravimetric-mass spectrometry (TG-MS).
• Evaluation as MOCVD precursors for MgO thin film deposition on silicon substrates, with characterization by SEM, EDX, XPS, and ellipsometry.

Main Results:

• Successful synthesis and structural determination of bis(ketoiminato)magnesium(ii) complexes [Mg(OCR²CH₂CHR¹NCH₂CH₂X)₂].
• Complexes 3a and 3c exhibit higher volatility (5.6 mbar and 2.0 mbar, respectively) compared to 3b (0.07 mbar) at 80 °C.
• MOCVD using complexes 3a and 3c yielded thin, dense MgO films (28-147 nm thickness) with low carbon content (3-4 mol%).

Conclusions:

• Bis(ketoiminato)magnesium(ii) complexes 3a and 3c are suitable MOCVD precursors for depositing high-quality MgO thin films.
• The volatility of the complexes directly influences the quality and deposition rate of the MgO films.
• Further research can explore tuning ligand structures to optimize precursor properties for advanced thin film applications.