The syntheses, characterization, thermal properties of asymmetrical La β-diketonate and their application as ALD precursor for La₂O₃ films

In this paper, three complexes La₂(thd)₆ (thd = 2,2,6,6-tetramethyl-3,5-heptanedione, 1)_, La₂(tmod)₆ (tmod = 2,2,6,6-tetramethyl octane-3, 5-dionates, 2) and La₂(ibpm)₆ (ibpm = 2,2,6-trimethyl-3, 5-heptane-dionates, 3) were synthesized by one-step method and characterized with ¹H-NMR, ¹³C-NMR and X-ray single-crystal diffraction. The melting point and TGA data demonstrated that the asymmetry of the ligand and the number of flexible joints could improve the volatility of the complex. With the help of asymmetry and flexible joint, La₂(tmod)₆ was selected as ALD precursor to deposit La₂O₃ film on SiO₂/Si (100) wafer. The self-limited deposition results demonstrated that La₂(tmod)₆ is better precursor than reported La₂(thd)₆ and La(thd)₃-DMEA (DMEA = N,N-dimethylethylenediamine).