Group 13 β-Ketoiminate Compounds: Gallium Hydride Derivatives As Molecular Precursors to Thin Films of Ga₂O₃

Bis­(β-ketoimine) ligands, [R­{N­(H)­C­(Me)-CHC­(Me)O}2] (L1H2, R = (CH2)2; L2H2, R = (CH2)3), linked by ethylene (L1) and propylene (L2) bridges have been used to form aluminum, gallium, and indium chloride complexes [Al­(L1)­Cl] (3), [Ga­(Ln)­Cl] (4, n = 1; 6, n = 2) and [In­(Ln)­Cl] (5, n = 1; 7, n = 2). Ligand L1 has also been used to form a gallium hydride derivative [Ga­(L1)­H] (8), but indium analogues could not be made. β-ketoimine ligands, [Me2N­(CH2)3N­(H)­C­(R′)-CHC­(R′)O] (L3H, R′ = Me; L4H, R′ = Ph), with a donor-functionalized Lewis base have also been synthesized and used to form gallium and indium alkyl complexes, [Ga­(L3)­Me2] (9) and [In­(L3)­Me2] (10), which were isolated as oils. The related gallium hydride complexes, [Ga­(Ln)­H2] (11, n = 3; 12, n = 4), were also prepared, but again no indium hydride species could be made. The complexes were characterized mainly by NMR spectroscopy, mass spectrometry, and single crystal X-ray diffraction. The β-ketoiminate gallium hydride compounds (8 and 11) have been used as single-source precursors for the deposition of Ga2O3 by aerosol-assisted (AA)­CVD with toluene as the solvent. The quality of the films varied according to the precursor used, with the complex [Ga­(L1)­H] (8) giving by far the best quality films. Although the films were amorphous as deposited, they could be annealed at 1000 °C to form crystalline Ga2O3. The films were analyzed by powder XRD, SEM, and EDX.双(β-二酮亚胺)（bis(β-ketoimine)）配体[R{N(H)C(Me)-CHC(Me)=O}2]（其中L1H2的R=(CH2)2，L2H2的R=(CH2)3），通过亚乙基（L1）和亚丙基（L2）桥联，被用于合成铝、镓、铟的氯化物配合物[Al(L1)Cl]（3）、[Ga(Ln)Cl]（4，n=1；6，n=2）以及[In(Ln)Cl]（5，n=1；7，n=2）。 配体L1还被用于合成一种镓氢化物衍生物[Ga(L1)H]（8），但无法制备其铟类似物。 带有给体官能化路易斯碱的β-二酮亚胺配体[Me2N(CH2)3N(H)C(R')-CHC(R')=O]（其中L3H的R'=Me，L4H的R'=Ph）也已被合成，并用于构建镓和铟的烷基配合物[Ga(L3)Me2]（9）与[In(L3)Me2]（10），二者均以油状物形式分离得到。 相关的镓氢化物配合物[Ga(Ln)H2]（11，n=3；12，n=4）也被制备出来，但同样无法得到铟氢化物物种。 上述配合物主要通过核磁共振波谱（NMR spectroscopy）、质谱以及单晶X射线衍射进行表征。 β-二酮亚胺基镓氢化物化合物（8和11）已被用作单源前驱体，以甲苯为溶剂，通过气溶胶辅助化学气相沉积（AA-CVD）沉积氧化镓（Ga2O3）薄膜。薄膜的质量随所用前驱体的不同而有所差异，其中配合物[Ga(L1)H]（8）制备得到的薄膜质量最佳。 尽管沉积态薄膜为非晶态，但可通过1000℃退火处理得到结晶态Ga2O3。薄膜通过粉末X射线衍射（XRD）、扫描电子显微镜（SEM）以及能量色散X射线能谱（EDX）进行了分析。