Magnesium bis (5-N-(N,N-dimethylaminopropyl)-2,2,7-trimethyl-3-octanonate) has been tested as a CVD precursor for the growth of MgO thin films on silicon substrates at 450 °C under an inert Ar atmosphere. Film composition was checked by XPS. Films grown with this precursor had granular morphology by SEM.
The molecular structure of the compound, determined by the single-crystal X-ray diffraction, presents a six-coordinate magnesium atom surrounded by four nitrogen and two oxygen atoms in an octahedral environment; it crystallizes in the triclinic space group P1¯.[220] Mg(dmto)2 containes β-ketiminato ligand core connected by an alkyl chain to a pendant amine donor ligand, the latte ones lead to a sterically saturated octahedral geometry at the magnesium center, preventing formation of an low volatility oligomers. MgO films were grown from this precursor at 450°C, without adding O2 to form the oxide. [4]
Magnesium β-ketoiminates/ β-diketiminate with ligands having dimethylamino substituents on the ligand core nitrogen atoms Mg(L2)2(4-tBupy)2, [Mg(L2)2]2, Mg(L3)2(4-tBupy)2, Mg(L3)2, [MgCp(L2)]2 and [MgCp(L3)]2 complexes (L1H = 4-(2,2-dimethylhydrazino)dimethylhydrazone-3-penten-2-one, L2H = 4-(2,2-dimethylhydrazino)-3-penten-2-one, L3H = 5-(2,2-dimethylhydrazino)-2,6-dimethyl-4-hepten-3-one), 4-tBupy = 4-tert-butylpyridine) were reported to sublime without decomposition at moderate temperatures and low pressures and were proposed as potential precursors for thin film growth using MOCVD and related techniques.
Thus, sublimation of Mg(L2)2(4-tBupy)2 or Mg(L3)2(4-tBupy)2 at 95–100 °C/0.05 Torr afforded [Mg(L2)2]2 (94%) and Mg(L3)2 (80%) as colorless crystalline solids. The crystal/molecular structures of Mg(L3)2(4-tBupy)2, [Mg(L2)2]2, Mg(L3)2, [MgCp(L2)]2, and [MgCp(L3)]2 have.been determined by single-crystal XRD
The cyclopentadienylmagnesium-ketoiminates [MgCp(L2)]2 and [MgCp(L3)]2 disproportionate upon attempted sublimation at 125–130 °C/0.05 Torr affording Cp2Mg (47–53%) and [Mg(L2)2]2 (67%) or Mg(L3)2 (74%). [[i]]
[i] Baburam Sedai, Mary Jane Heeg and Charles H. Winter, Journal of Organometallic Chemistry, Vol.693, Issue 23, 1 November 2008, Pages 3495–3503, “Magnesium complexes containing β-ketiminate and β-diketiminate ligands with dimethylamino substituents on the ligand core nitrogen atoms”