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).