In this study, n-diamond–carbon nanowalls hybrid structure was synthesized on a 4-inch diameter silicon wafer by RF-PECVD technique (type CCP). A comprehensive analysis of the structure was carried out at the beginning of growth and after a long period of synthesis using electron microscopy, transmission microscopy, Raman spectroscopy, and X-ray diffraction techniques. As the analysis showed, feeding carbon monoxide (CO) to a gas mixture of methane (CH4), argon (Ar), and hydrogen (H2) induces the formation of n-diamond particles in a basal layer. By using plasma-enhanced etching in an oxygen-containing medium, carbon nanowalls (CNWs) were successfully removed, and the underlying layer containing n-diamond was analyzed. For the first time, X-ray diffraction results of a separate n-diamond phase were obtained for this layer.

A method is presented for the deposition of ultrathin superconducting NbN x films by atomic layer deposition enhanced by plasma from an organometallic precursor and an H 2 /Ar gas mixture used as a reactant. The samples obtained are characterized by measurements of resistivity, spectral ellipsometry, atomic force microscopy, and measurements of superconducting characteristics. The optimal parameters of the H 2 /Ar gas ratio are determined at which the resistivity of the NbN x films is minimal. A comparative analysis of the resistivity of the obtained NbN x films is carried out. The dependence of the temperature of transition to the superconducting state on film thickness is investigated. A transition temperature of 13.7 K and a critical current density of 0.7 MA/cm 2 are reached. The high film uniformity, precision control of the thickness, and deposition temperature of 350°C make it possible to use these films in the production of field-effect transistors and in functional devices for various purposes, for example, in hot-electron bolometers, kinetic inductance detectors, and superconducting single-photon detectors.

Hydromechanical impact on an array of horizontally aligned carbon nanotubes during the creation of a functional layer of future devices is studied. The carbon-nanotube layer is formed by the spray-coating technique. A method for controlling the surface resistance of the nanotube layer deposited onto the substrate surface before and after hydromechanical treatment is demonstrated. The wafer surface with carbon nanotubes is examined by scanning electron microscopy and Raman spectroscopy. An original technique for the uniform deposition of a carbon-nanotube layer with desired properties is proposed. The results obtained show that this technique makes it possible to obtain a carbon-nanotube layer with a specified surface resistance, which depends on the concentration of the suspension used and subsequent processing of the resulting layers, on the substrate surface.

This publication presents a method for deposition of ultrathin superconducting NbNx films by atomic layer deposition enhanced by plasma with metal-organic precursor and a gas mixture of H2/Ar used as reactant. The obtained films characterized by measuring of sheet resistance, ellipsometry, atomic force microscopy, and superconducting characteristics measurements. The optimal parameters of the H2/Ar gas ratio was defined at which sheet resistance of NbNx films was minimal. A comparative analysis of sheet resistance of the obtained NbNx films performed. The dependence of the transition temperature to the superconducting state on the film thickness investigated. The transition temperature of 13.7 K and the critical current density of 0.7 MA/cm2 achieved. High film uniformity, precision control of the thickness and deposition temperature of 350°C makes it possible to use these films in the manufacture of field effect transistors and in functional devices for various purposes, working on the superconductivity effect.

The influence of the buffer layer of hafnia dielectric on superconducting properties of niobium nitride films, produced by the technique of the reactive magnetron depositing has been investigated for the first time. This study presents a comprehensive analysis of morphological, microstructural, and electrophysical parameters of thin NbN films.

This study presents a multistep process of plasma-enhanced atomic layer deposition of ultrathin superconductive films of niobium nitride from metal organic precursor tris(diethylamido)(tert-butylimido)niobium(V). While using NH3/Ar and H2/Ar gas mixtures as reactants, a comprehensive analysis was performed pertaining to the influence of operating parameters, such as the duration of plasma exposure to the H2/Ar reactant, gas-flow ratio, plasma exposure duration and power of inductively coupled plasma source for the NH3/Ar reactant, on the obtained films' parameters, such as resistivity, superconducting transition temperature and critical current density. Amorphous silicon oxide was used as the substrate. It was shown by experiments, that films' resistivity affects the value of critical current density. As a result, the all-time record resistivity of 147 µΩ·cm was achieved for films with a thickness of 8 nm. When cooling in the Gifford McMahon closed-cycle cryostat, the values of superconducting transition temperature and critical current density were equal to 12.3 К and 9 МА/cm2 at a liquid helium temperature, respectively.

Vertically oriented graphene structures have a high specific surface area which makes them potential candidates for realization of various devices. On their basis, supercapacitors, lithium-ion batteries, absorbing coatings and bolometers, gas and electrochemical sensors, and other devices have been demonstrated. At the same time, such structures for conventional capacitors remain unexplored. In this research the fabrication technology of quasi three-dimensional capacitors based on metal/carbon nanowalls/insulator/metal structure (MCNWIM) are demonstrated. Carbon NanoWalls (CNWs) were used as a base electrode to increase the specific surface area of capacitors. Uniform dielectric and metal layers of aluminum oxide (AlOx) and titanium nitride (TiNx) were deposited by thermal atomic layer deposition (ALD) and plasma-enhanced atomic layer deposition (PEALD). A comparative analysis of ca-pacitors with and without a carbon nanostructure has been performed. The influence of dielectric thickness on the capacitance density as well as dependencies of breakdown voltage on the surface area were experimentally observed. The maximum capacitance density was 3.6 mF/cm2 at the AlOx thickness of 10 nm, which is 4.7 times higher than the values of capacitors without carbon nanostructure. The investigated structures were manufactured on four-inch silicon wafers that provide the possibility of the mass production of capacitors based on CNWs. (c) 2021 Elsevier Ltd. All rights reserved.

This study presents dielectric properties investigation of hafnium oxide (HfOx), aluminum oxide (AlOx) and tantalum oxide (TaOx) thin films and HfAlTaOx compound based on their multilayer structure. The thickness of all films under study was 40 nm. The investigated films were produced from metal-organic precursors by Plasma Enhanced Atomic Layer Deposition (PEALD). Based on the dielectrics mentioned above, we produced Metal - Insulator - Metal (MIM) capacitors and researched their properties. Dielectric constant for HfOx, AlOx, TaOx and HfAlTaOx was 20, 9, 31 and 13, correspondingly. Volumetric efficiency of MIM capacitors based on HfOx, AlOx, TaOx and HfAlTaOx was 4.4 nF/mm(2), 2 nF/mm(2), 6.8 nF/mm(2) and 2.9 nF/mm(2), correspondingly. Dielectric strength of HfAlTaOx compound was significantly higher (8.2 MV/cm) compared to other dielectrics: HfOx (3.6 MV/cm), AlOx (6.4 MV/cm), TaOx (1.5 MV/cm). The greatest values were observed in the compound of significantly higher dielectric strength which is comparable to silicon oxide. This study was the first to demonstrate the advantages of the produced compound, such as high dielectric constant and dielectric strength. (C) 2020 Elsevier B.V. All rights reserved.

Влияние буферного слоя на формирование катализатора на основе тонкой пленки никеля для синтеза углеродных нанотрубок

The formation of nanoparticles of a thin-film nickel catalyst applied on a buffer layer in the form of pure titanium, titanium oxide, or titanium nitride has been studied. It has been shown that if nanotubes are synthesized in three stages (oxidation, reduction, and growth of nanotubes), the situation may arise when the metallic catalyst becomes isolated from the surface, and hence, from the hydrocarbon flux, as a result of which the nanotube growth stops. Isolation takes place when the interface between titanium oxide and the gas phase in the reactor moves. In this case, titanium oxide goes round a nickel oxide nanoparticle and insulates it. The displacement rate of this interface and the coefficient of hydrogen diffusion in titanium dioxide have been determined.

A new method for determining the thickness of opaque films on bulk substrates is considered in the nanometer size range. The method is based on analysis and measurements of the energy spectra of back-scattered electrons. The thicknesses of local film nanostructures are determined from the amplitude values of the spectra and from their shift on the energy axis.

Basic principles of charging dielectric films on conducting substrates upon irradiation with electrons of average energy are considered. A ratio associating the equilibrium charging potential and the mean thickness of the dielectric film is calculated. The analytical expression is in good agreement with experimental results over a wide range of energies for electrons irradiating the target.

A critical survey of the current state of the problem of visualizing local impurity regions of semiconductor crystals in a scanning electron microscope (SEM) is presented. A new physicotechnical solution for monitoring impurity distributions in doped regions that allows us to increase the contrast between images of impurity sectors in a wide range of concentrations is proposed.

The structure of amorphous linear-chain carbon (LCC) during the structure formation under conditions of vacuum annealing was studied by electron diffraction and Raman spectroscopy methods. It was shown that the determining factor of lowering the work function of the LCC coating is the formation of nanoclusters of mutually misoriented short carbon chains.