Alexander Jakob

Copper Oxide Films Grown by Atomic Layer Deposition from Bis(tri-n-butylphosphane)copper(I)acetylacetonate on Ta, TaN, Ru, and SiO2

The thermal atomic layer deposition (ALD) of copper oxide films from the nonfluorinated yet liquid precursor bis(tri-n-butylphosphane)copper(I)acetylacetonate, [( n Bu 3 P) 2 Cu(acac)], and wet O 2 on Ta, TaN, Ru, and SiO 2 substrates at temperatures of < 160°C is reported. Typical temperature-independent growth was observed at least up to 125°C with a growth-per-cycle of ∼0. A for the metallic substrates and an ALD window extending down to 100°C for Ru. On SiO 2 and TaN, the ALD window was observed between 110 and 125°C, with saturated growth shown on TaN still at 135°C. Precursor self-decomposition in a chemical vapor deposition mode led to bimodal growth on Ta, resulting in the parallel formation of continuous films and isolated clusters. This effect was not observed on TaN up to ∼130°C and neither on Ru or SiO 2 for any processing temperature. The degree of nitridation of the tantalum nitride underlayers considerably influenced the film growth. With excellent adhesion of the ALD films on all substrates studied, the results are a promising basis for Cu seed layer ALD applicable to electrochemical Cu metallization in interconnects of ultralarge-scale integrated circuits.

Bis(β-diketonato)- and allyl-(β-diketonato)-palladium(II) complexes: synthesis, characterization and MOCVD application

The syntheses and characterization of the palladium complexes [Pd(accp)2] (7), [Pd(acch)2] (8), [Pd(η3-CH2CMeCH2)(accp)] (11), [Pd(η3-CH2CMeCH2)(acch)] (12), [Pd(η3-CH2CtBuCH2)(accp)] (13) and [Pd(η3-CH2CtBuCH2)(acch)] (14) (accp = 2-acetylcyclopentanoate; acch = 2-acetylcyclohexanoate) are reported. These complexes are available by the reaction of Haccp (2-acetylcyclopentanone) and Hacch (2-acetylcyclohexanone) with Na2[Pd2Cl6] forming 7 and 8 or with [(Pd(η3-CH2CRCH2)(μ-Cl))2] (9, R = Me; 10, R = tBu) forming 11–14. The molecular structures of 7, 8 and 14 are discussed. Complexes 7 and 8 consist of a square-planar coordinated Pd atom with two trans-positioned bidentate β-diketonate ligands. The asymmetric unit of 14 exhibits one molecule of the palladium complex and a half molecule of water. The thermal behavior of 7, 8 and 11–14 and their vapor pressure data were investigated to show, if the appropriate complexes are suited as CVD precursors for palladium layer formation. Thermogravimetric studies showed the evaporation of the complexes at atmospheric pressure upon heating. The vapor pressure of 7, 8 and 11–14 was measured by using thermogravimetric analysis, giving vapor pressure values ranging from 0.62 to 2.22 mbar at 80 °C. Chemical vapor deposition studies were carried out applying a vertical cold wall CVD reactor. Either oxygen or forming gas (N2/H2, ratio 90/10, v/v) was used as reactive gas. Substrate temperatures of 350 and 380 °C were utilized. With 11–14 dense and conformal as well as particulate palladium films were obtained, as directed by SEM studies, whereas 7 and 8 failed to give thin films, which is probably attributed to their high thermal stability in the gas phase. For all deposited layers, XPS measurements confirmed the partial oxidation of palladium to palladium(II) oxide at 380 °C, when oxygen was used as reactive gas. In contrast, thin layers of solely metallic palladium were obtained utilizing forming gas during the deposition experiments.

Ferrocenyl β-diketonato-based Cu(II)-oxo clusters with Cu7 and Cu10 cores

Crystallization of [Cu(β-diketonate)(PPh3)2] (1a, β-diketonate=1-ferrocenyl-butane-1,3-dionato (= fb); 1b, = 1,3-diferrocenyl-propane-1,3-dionato (= dfp)) from ethanol, layered with a mixture of pentane/diethyl ether of ratio 1 : 1 (v/v) in air, afforded Cu(II)-oxo clusters [Cu10(fb)8(O)4(tmdd)2]·1.5Et2O (2) and [Cu7(dfp)6(O)2(OH)2(tmdd)]·2Et2O (3), respectively, in minor yield (tmdd = 1κ 2 C,3κ 2 C-tetramethyldisiloxane-1,3-diolato). These clusters were obtained in somewhat better yield when HOSiMe2OSiMe2OH was added to the crystallization mixtures. The molecular structures of 2 and 3 in the solid state are reported.

(1-Ferrocenyl-4,4,4-trifluoro-butane-1,3-dionato-κO,O)bis-(triphenyl-phosphane)copper(I).

In the title mononuclear coordination complex, [CuFe(C5H5)(C9H5F3O2)(C18H15P)2], the CuI ion is coordinated by the chelating β-diketonate 1-ferrocenyl-4,4,4-trifluorobutane-1,3-dione ligand through two O atoms and the two datively bonded triphenylphosphane ligands resulting in a distorted tetrahedral coordination sphere. The CuI ion, together with its chelating butane-1,3-dione group, is mutually coplanar [greatest displacement of an atom from this plane = 0.037 (1) Å], and the CuI ion lies slightly above [0.013 (1) Å] the plane. The overall geometry, including the bond distances and angles within the complex, corresponds to those of other reported copper(I) β-diketonates featuring organic groups at the β-diketonate ligand.

Crystal structure of cyclo-bis­(μ4-2,2-di­allyl­malonato-κ6O1,O3:O3:O1′,O3′:O1′)tetra­kis­(triphenyl­phosphane-κP)tetra­silver(I)

In the title compound, the silver(I) ions are coordinated by four triphenylphosphane ligands and two 2,2-diallylmalonate anions in a μ4-(κ6 O 1,O 3:O 3:O 1′,O 3′:O 1′) mode, setting up an Ag4O8P4 core.

Synthesis of [{AgO2CCH2OMe(PPh3)}n] and theoretical study of its use in focused electron beam induced deposition

The synthesis, chemical and physical properties of [{AgO2CCH2OMe}n] (1) and [{AgO2CCH2OMe(PPh3)}n] (2) are reported. Consecutive reaction of AgNO3 with HO2CCH2OMe gave 1, which upon treatment with PPh3 produced 2. Coordination compound 2 forms a 1D coordination polymer in the solid state as evidenced by single crystal X-ray structure analysis. The coordination geometry at Ag+ is of the [3 + 1] type, whereby the carboxylate anions act as bridging ligands. The formation of PPh3–Ag(I) coordinative bonds results in distorted T-shaped AgPO2 units, which are stabilized further by an additional O–Ag dative bond. TG and TG–MS measurements show that 1 and 2 decompose at 190–250 °C (1) and 260–300 °C (2) via decarboxylation, involving Ag–P (2), C–C and C–O bond cleavages to give elemental silver as confirmed by PXRD studies. In order to verify if polymeric 2 is suitable as a FEBID precursor for silver deposition, its vapor pressure was determined (p 170 °C = 5.318 mbar, ∆H vap = 126.1 kJ mol−1), evincing little volatility. Also EI and ESI mass spectrometric studies were carried out. The dissociation of the silver(I) compound 2 under typical electron-driven FEBID conditions was studied by DFT (B3LYP) calculations on monomeric [AgO2CCH2OMe(PPh3)]. At an energy of the secondary electrons up to 0.8 eV elimination of PPh3 occurs, giving Ag+ and O2CCH2OMe−. Likewise, by release of PPh3 from [AgO2CCH2OMe(PPh3)] the fragment [AgO2CCH2OMe]− is formed from which Ag+ and O2CCH2OMe− is generated, further following the first fragmentation route. However, at 1.3 eV the initial step is decarboxylation giving [AgCH2OMe(PPh3)], followed by Ag–P and Ag–C bond cleavages.

Crystal structure of an unknown tetra­hydro­furan solvate of tetra­kis­(μ3-cyanato-κ3N:N:N)tetra­kis­[(triphenyl­phosphane-κP)­silver(I)]

In the title compound a distorted Ag4N4-heterocubane core is set up by AgI cations and N atoms of cyanate anions. The core is decorated by four triphenylphosphine ligands bonded to the AgI cations. Ag⋯Ag distances as short as 3.133 (9) Å suggest the presence of argentophilic (d 10⋯d 10) interactions.