Synthesis and thermal behavior of [Li(thf)3(μ-Cl)La{N(SiMe3)2}3] and its investigation as spin-coating precursor for lanthanum-based layer formation

The lanthanum（Ⅲ） complex [Li（thf）3（μ-CI）La{N（SiMe3）2}3]（3） was obtained by the reaction of LaCl3 with three equiv of Li[N（SiMe3）2]3 in a tetrahydrofuran solution. The molecular structure of 3 in the solid state was characterized by a tetracoordinated anionic lanthanide（Ⅲ） amide in form of an adduct with LiCl（thf）3 as evidenced by single crystal X-ray structure analysis. In order to study the suitability of 3 as a precursor for the deposition of La2O3/LiLaSiO4 by thin layer deposition techniques,its thermal behavior was investigated by thermogravimetry（TG） and TG-MS-coupled studies. TG studies show a two-step decomposition process, whereby volatile decomposition products can be detected during the second decomposition step. TG measurements under an atmosphere of oxygen produced La2O3, Calcination processes of 3 under ambient atmosphere for 10 h at 1000 ℃ gave La2O3 and LiLaSiO4,which was confirmed by PXRD studies. Metal-organic 3 was applied as spin-coating precursor for La2O3 thin film formation giving the as-deposited layers nearly crack-free.

Tetranuclear yttrium and gadolinium 2-acetylcyclopentanoate clusters：Synthesis and their use as spin-coating precursors for metal oxide film formation for field-effect transistor fabrication

Lanthanide clusters [Ln4（μ3-OH）2（η2-accp）4（（μ-O）-η2-accp）6]（Ln = Y（4）,Gd（5）; accp = 2-acetylcyclopentanoate） are accessible by treatment of [M（NO33·6 H2 O]（M = Y（1）,Gd（2）） with 3 equiv. of Haccp（3） in presence of NaOH. The molecular structures of 4 and 5） in the solid-state are discussed. The thermal behavior of 4 and 5 was studied by TG under Ar and O2, showing multistep decomposition processes. Additionally, DSC studies were carried out under an atmosphere of O2. PXRD measurements of the TG residues confirm the formation of Ln2 O3.Spin-coating experiments were carried out with 4 and 5 for Ln2 O3 film deposition on silicon substrates. The layers are smooth, close and are of thicknesses of 18.87±1.13 nm and 25.59 ± 4.55 nm for Ln = Y and Gd, which was evidenced by SEM and EDX studies. Field-effect transistors were successfully fabricated by deposition of carbon nanotubes on top of the Y2 O3 films and formation of palladium contacts by a lift-off procedure. An on/off ratio of more than 4 orders of magnitude is achieved without considerable leakage currents. These results demonstrate the potential use of spin-coated Y2 O3 as a gate dielectric in electronic devices.

[Y(dbm)_(3)(H_(2)O)]:Synthesis,thermal behavior and spin-coating precursor for Y_(2)O_(3)layer formation

The synthesis,structure and thermal behavior of [Y（dbm）3（H2 O）]（3）（dbm = 1,3-diphenyl-1,3-propandionate） and its use as a spin-coating precursor for Y2 O3 deposition is reported. Complex 3 was prepared by the reaction of [Y（NO3）3·6 H2 O]（1） with 3 equiv of Hdbm（2） in presence of NaOH. The molecular structure of 3 in the solid-state was determined by single X-ray crystal diffraction. Both C1 symmetric crystallographically independent species of 3 possess a YO7 coordination setup with minor deviation from an ideal capped octahedron coordination geometry（∧ enantiomer）. Complex 3 forms a1 D chain, due to intermolecular hydrogen bonds between the coordinated H2 O molecule and the 0 atom of the dbm ligand, respectively. The thermal decomposition behavior of 3 was investigated by thermogravimetric studies in the temperature range of 40-800 ℃ and 40-1300 ℃ under an oxygen and argon atmosphere, respectively. Powder X-ray diffraction（PXRD） measurements of the residues confirmed the formation of Y2 O3. Complex 3 was applied as a spin-coating precursor for yttrium oxide film formation on either Si wafers with a continuous 100 nm thick SiO2 film, or with a native oxide layer.The as-deposited Y2 O3 layers are smooth, conformal, dense and transparent and are of a thickness of 27 and 30 nm, respectively.