Sergey V. Trubin

Preparation of thin films of platinum group metals by pulsed MOCVD. II. Deposition of Ru layers

In situ high-temperature mass spectrometry is used to analyze the thermal decomposition of Ru(acac)3 and Ru(nbd)(allyl)2 vapor and possible schemes of thermal transformations on the heated surface. By pulsed MOCVD with in situ mass spectrometric control of deposition processes ultrathin Ru layers with a thickness of several nanometers are obtained. The role of the reaction medium, precursor nature, and deposition temperature in the formation of a nanocrystalline structure of the films is revealed. Ruthenium films with a compact continuous structure are formed from Ru(acac)3 and hydrogen at a deposition temperature of 340°C and below; an increase in the temperature results in the growth of nanogranular Ru layers. Regardless of deposition conditions, from Ru(nbd)(allyl)2 granular nanocrystalline Ru layers are formed

Synthesis and thermal properties of some lithium β-diketonates

Five new volatile lithium complexes were synthesized by reactions of lithium hydroxide monohydrate (LiOH · H2O) with β-diketones, namely, dipivaloylmethane (HDpm), hexafluoroacetylacetone (HHfa), trifluoroacetylacetone (HTfa), benzoyltrifluoroacetone (HBtfa), pivaloyltrifluoroacetone (HPta), and valeryltrifluoroacetone (HVta). The complexes obtained were studied by IR and electronic absorption spectroscopy, mass spectrometry, and comprehensive thermal analysis. The temperature dependence of the vapor pressure, which was obtained by the Knudsen effusion method with mass-spectrometric analysis of the vapor phase composition in the 400–450 K range, was used to calculate the standard thermodynamic parameters of the Li(Dpm) sublimation: ΔH°subl = 45.7 ± 1.7 kcal mol−1 and ΔS°subl = 77.9 ± 4.0 cal mol−1 K−1.

Thermal Properties of Some Volatile Titanium (IV) Precursors

The tensimetric study was carried out for TTIP, Ti[OEt]4 and Ti[DMAP]4 by means of static method with a quartz membrane zero-manometer and flow method using He as gas-carrier (the compounds were assumed to vaporize in a monomolecular form) in a wide range of temperatures. Temperature dependencies of saturated vapor pressure were measured; the evaporation thermodynamic parameters have been calculated (Table 1). Data obtained for TTIP can be compared with values calculated from literature data [1, 2].

Copper(II) complexes with Schiff bases: Structures and thermal behavior

Ligands with Schiff bases are obtained in the condensation of propylenediamine (pda) or 2,2-dimethylpropylenediamine (dmpda) with acetylacetone (Hacac) in the 1:2 molar ratio. The ligands are characterized by the elemental analysis methods, Tmelt = 90–92 °C for pda(Hacac)2 (pda(acac)2 is N,N′-propylene-bis(acetylacetoniminato) (2-)), Tmelt = 84–86 °C for dmpda(Hacac)2 (dmpda(acac)2 is N,N′-2,2-dimethylpropylene-bis(acetylacetoniminato) (2-)). The tautomerism of the ligands is established by the single crystal X-ray diffraction (XRD) analysis, IR spectroscopy, and 1H, 13C NMR spectrometry. The synthesized complexes [Cu(pda(acac)2)] (1), Tmelt = 121–122 °C and [Cu(dmpda(acac)2)] (2), Tmelt = 156–158 °C are studied by the XRD method. In both complexes, copper atoms have a planar square geometry, and the chelate bond lengths and angles are: Cu-O ≈ Cu-N 1.903(2)–1.942(3) Å, ∠O-Cu-N = 94.44(12)–94.99(12)° for 1 and Cu-O ≈ Cu-N 1.909(1)–1.943(2) Å, ∠O-Cu-N = 94.63(6)° for 2. By the thermogravimetric method it is found that both complexes can be passed practically quantitatively into the gas phase.

Thermal properties of dimethylgold(III) 8-hydroxyquinolinate and 8-mercaptoquinolinate

Dimethylgold(III) complexes with 8-hydroxyquinoline Me2Au(Ox) (I) and 8-mercaptoquinoline Me2Au(Tox) (II) were synthesized and studied. Complex II obtained for the first time was identified from the elemental analysis, IR, 1H NMR, and mass spectrometry data. The thermal properties of complexes I, II in condensed state were investigated by thermography. The temperature dependences of the saturated vapor pressure over crystals were measured by the Knudsen effusion method with mass spectrometric recording of the gas phase composition and the thermodynamic characteristics of the sublimation process were determined: for I, log P[Torr] = (14.6 ± 0.3) − (6.34 ± 0.10) × 103/(T, K), Δ Hsublo = 121.2 ± 1.9 kJ−1, Δ Ssublo = 224.1 ± 4.6 J mol−1 K−1 (the temperature interval under study 80–115°C); for II, log P [Torr] = (13.3 ± 0.2) − (6.30 ± 0.09) × 103/(T, K), Δ Hsublo = 120.5 ± 1.7 kJmol−1, ΔSsublo = 199.3 ± 3.0 J mol−1 K−1 (86–145°C).

Thermoanalytical and mass spectrometric study of Ni(iso-Bu2PS2)2 and NiL(iso-Bu2PS2)2 (L = 2,2′-Bipy, Phen). Saturation vapor pressure over the Ni(iso-Bu2PS2)2 chelate

The thermal behaviors of the chelate Ni(iso-Bu2PS2)2 (I) and the mixed-ligand complexes Ni(2,2′-Bipy)(iso-Bu2PS2)2 (II) and Ni(Phen)(iso-Bu2PS2)2 (III) in air are reported. These compounds can pass into the gas phase, as was demonstrated by vacuum sublimation for I and by vacuum distillation for II and III in a gradient furnace. The mass spectra of I–III are presented and discussed. The temperature dependence of the saturation vapor pressure over I and ΔHT0 and ΔST0 and of evaporation of I determined by the vapor transport method are reported.

Low-Temperature VUV-Stimulated MO CVD Process of Palladium Layer Deposition

Attention to low-temperature processes of metal film deposition is due to the necessity to obtain electrically conducting layers on different surfaces including those containing polymeric regions. The use of a highly volatile precursor, for example Pd(hfa)2, with simultaneous stimulation of its decomposition in the atmosphere of hydrogen using the VUV radiation of excimer lamps with the wavelength 116 to 126 nm allows one to decrease the temperature for the deposition of mirror metal films. In the present work, the composition and morphology of palladium films are examined by means of scanning electron microscopy, ESCA, spectral ellipsometry, depending on the temperature of substrate and precursor, deposition time, flow rates of hydrogen and argon. The nature of the substrate, its activation by VUV radiation allow selective deposition of palladium films on combined substrates (metal - polymer) with a complicated spatial relief.

Structure of platinum coatings obtained by chemical vapor deposition

To the best of our knowledge, it is the first time that the method of chemical vapor deposition (MOCVD) with platinum(II) bis(acetylacetonate) (Pt(acac)2) is used to obtain platinum coatings on the cathodes and anodes of the electrodes for pacemakers. The deposition processes are carried out under reduced pressure in the presence of oxygen. The phase and elemental composition, structure, and morphology of the coatings are examined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Platinum coatings with a columnar structure are prepared in the temperature range 280-340°C. An increase in the deposition temperature leads to a change in the structure of the coatings and reduction in their thickness. Cyclic voltammetry (CV) is used to estimate the specific capacities of the platinum coatings on the cathodes and anodes, the maximum values of which are 426 mC/cm2 and 1160 mC/cm2, respectively.

The study on electro-physical properties of sandwich structures based on fullerite films

We report on the technology of formation of sandwich structures based on fullerite films and on experimental results in research of optical and conductivity properties of these sandwich samples. Single crystals of sapphire (100) or silicon were used as substrates. The sandwich specimens were based on the structure M/C/sub 60//M (M=Cr, Pd, Ag, Al, Cu). The thickness of the fullerite films was /spl sim/0.2-1.0 /spl mu/m. The area of the C/sub 60/ film under the top contact was /spl sim/1 cm. The specimens have been investigated by infrared spectroscopy, spectrophotometry, ellipsometry and X-ray diffraction analysis. Measurements of the current/voltage characteristics and research on the temperature dependence of conductivity were performed as well. It was shown that metals such as Cr, Pd, Ag, Al, and Cu penetrate easily into the fullerite films. It appears that these specimens have a large conductivity. For silver/C/sub 60/ and other sandwich structures the conductivities show a semiconductor-like behaviour.