The Preparation and Properties of Volatile Tris(N-Alkoxycarboxamidato)chromium(III) Complexes as Potential Single-Source Precursors for the MOCVD of Crystalline Chromium Oxide Thin Films

High Resolution Image Download MS PowerPoint Slide The synthesis, characterization, and vapor-phase growth of volatile Cr(III) complexes as single-source precursors for Cr 2 O 3 thin films are reported. A series of Cr complexes─Cr(mdpa) 3 (mdpa = N -methoxy-2,2-dimethylpropanamide) ( 1 ), Cr(edpa) 3 (edpa = N -ethoxy-2,2-dimethylpropanamide) ( 2 ), Cr(empa) 3 (empa = N -ethoxy-2-methylpropanamide) ( 3 ), and Cr(mpa) 3 (mpa = N -methoxypropanamide) ( 4 )─were synthesized via salt elimination reactions between CrCl 3 ·3THF and N -alkoxy carboxamidate salts. These complexes were characterized by Fourier transform infrared spectroscopy, elemental analysis, thermogravimetric analysis (TGA), single-crystal X-ray diffraction (SC-XRD), Hirshfeld surface analysis, powder X-ray diffraction (PXRD), and vapor pressure measurement. The crystal structure of complex 1 revealed a distorted octahedral geometry with a κ 2 (O,O) binding mode. TGA demonstrated that complex 1 underwent weight loss at 132 °C and no residue remained at 500 °C. The enthalpy of vaporization of 1 was estimated to be 25.58 kJ/mol, making it an optimal precursor for Cr 2 O 3 thin films. The XRD patterns of Cr 2 O 3 films deposited on SiO 2 /Si substrates confirmed their crystalline nature, showing prominent peaks at 2θ = 33.5° and 41.5°. In addition, X-ray photoelectron spectroscopy validated the target Cr/O ratio, supporting the successful formation of Cr 2 O 3 films.