M. N. Drozdov

Nizhny Novgorod State University, Gorkey, Nizjnij Novgorod, Russia

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Publications (141)102.89 Total impact

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    ABSTRACT: We report on building a novel chemical vapor deposition (CVD) reactor for diamond delta-doping. The main features of our reactor are: a) the use of rapid gas switching system, (b) the reactor design providing the laminar gas flow. These features provide the creation of ultra-sharp interfaces between doped and undoped material and minimize the prolonged ”tails” formation in the doping profile. It is proved by optical emission spectroscopy that gas switching time is not more than 10 seconds. Using the novel reactor we have grown the nanometer-thin layers of boron doped diamond. The FWHM of boron concentration profile is about 2 nm which is proved by SIMS. It is shown that the both single delta-layer and multiple delta-layers could be grown using the novel CVD reactor. In principle, the reactor could be used for diamond delta doping with other dopants, like nitrogen, phosphorus etc. (© 2016 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)
    No preview · Article · Feb 2016 · physica status solidi (RRL) - Rapid Research Letters
  • A. V. Antonov · M. N. Drozdov · A. V. Novikov · D. V. Yurasov
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    ABSTRACT: The segregation of Sb in Ge epitaxial layers grown by the method of molecular beam epitaxy on Ge (001) substrates is investigated. For a growth temperature range of 180–325°C, the temperature dependence is determined for the segregation ratio of Sb in Ge, which shows a sharp increase (by more than three orders of magnitude) with increasing temperature. The strong dependence of the segregation properties of Sb on the growth temperature makes it possible to adapt a method based on the controlled use of segregation developed previously for the doping of Si structures for the selective doping of Ge structures with a donor impurity. Using this method selectively doped Ge:Sb structures, in which the bulk impurity concentration varies by an order of magnitude at distances of 3–5 nm, are obtained.
    No preview · Article · Nov 2015 · Semiconductors
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    ABSTRACT: A method for the in situ passivation of GaN-based structures with silicon nitride in the growth chamber of a metal organic vapor phase epitaxy (MOVPE) reactor is described. The structural and electrical properties of the obtained layers are investigated. The in situ and ex situ passivation of transistor structures with silicon nitride in an electron-beam-evaporation device are compared. It is shown that ex situ passivation changes neither the initial carrier concentration nor the mobility. In situ passivation makes it possible to protect the structure surface against uncontrollable degradation upon the finishing of growth and extraction to atmosphere. In the in situ passivated structure, the carrier concentration increases and the mobility decreases. This effect should be taken into account when manufacturing passivated GaN-based transistor structures.
    No preview · Article · Nov 2015 · Semiconductors
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    ABSTRACT: Antimony segregation in Ge(001) films grown by molecular beam epitaxy was studied. A quantitative dependence of the Sb segregation ratio in Ge on growth temperature was revealed experimentally and modeled theoretically taking into account both the terrace-mediated and step-edge-mediated segregation mechanisms. A nearly 5-orders-of-magnitude increase in the Sb segregation ratio in a relatively small temperature range of 180-350 °C was obtained, which allowed to form Ge:Sb doped layers with abrupt boundaries and high crystalline quality using the temperature switching method that was proposed earlier for Si-based structures. This technique was employed for fabrication of different kinds of n-type Ge structures which can be useful for practical applications like heavily doped n+-Ge films or δ-doped layers. Estimation of the doping profiles sharpness yielded the values of 2-5 nm per decade for the concentration gradient at the leading edge and 2-3 nm for the full-width-half-maximum of the Ge:Sb δ-layers. Electrical characterization of grown Ge:Sb structures revealed nearly full electrical activation of Sb atoms and the two-dimensional nature of charge carrier transport in δ-layers.
    Full-text · Article · Oct 2015 · Journal of Applied Physics
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    ABSTRACT: Original approach to fabricating a GaN/AlN/nanocrystalline diamond structure has been suggested and implemented. The stages of deposition of a structure of this kind include the following: (a) growth of nanocrystalline CVD-diamond on single-crystal AlN (preliminarily grown on a silicon substrate), (b) etch removal of the silicon substrate, and (c) growth of single-crystal GaN on the surface of single-crystal AlN. Single-crystal gallium nitride with a width of the X-ray rocking curve for the (0002) reflection of 0.35° was obtained on a nanocrystalline-diamond substrate.
    Full-text · Article · May 2015 · Technical Physics Letters
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    Full-text · Article · Mar 2015
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    ABSTRACT: It was demonstrated that the low-coherence interferometry technique can be successfully applied to real-time substrate temperature evaluation during molecular beam epitaxy in a wide range down to room temperature. The proposed technique was used for formation of silicon layers delta-doped by antimony. Due to shortening of the growth interruptions needed for temperature switching the low-coherence interferometry technique allows improving the crystal quality of the grown samples and reducing the material and time consumption. These advantages become extremely beneficial with lowering of the growth temperatures.
    No preview · Article · Mar 2015 · Journal of Crystal Growth
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    ABSTRACT: Hexagonal single-crystalline indium nitride (InN) films on (0001)-oriented sapphire (Al2O3) and (111)-oriented fianite (yttria-stabilized zirconia, YSZ) substrates and on (0001)-oriented GaN/Al2O3 templates have been grown at a record high rate of 10 μm/h by the method of metalorganic vapor phase epitaxy with nitrogen activation in plasma of electron cyclotron resonance discharge generated by gyrotron radiation. It is established that the use of fianite substrates significantly improves the structural perfection and photoluminescent properties of InN films as compared to those grown on sapphire and templates. Undoped InN films exhibit n-type conductivity with electron concentrations within n = 8.0 × 1019-4.9 × 1020 cm−3 and room-temperature mobilities up to 180 cm2/(V s).
    No preview · Article · Mar 2015 · Technical Physics Letters
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    ABSTRACT: Time-of-flight Secondary Ion Mass Spectrometry and High-resolution Transmission Electron Microscopy study is reported on depth profiling of 375 nm-thick multilayer La/B4C interferential mirrors produced by magnetron sputtering for X-ray radiation at the wavelength of 6.7 nm. The introduction of ultra-thin (0.5 nm) carbon barrier layer inside each period of ca. 7.5 nm suppressed the broadening of interface regions, decreased the width of La and B profiles and as a result improved the reflectance of mirrors. Depending on the layers’ sequence (La/C/B4C or La/B4C/C upward the Si substrate), two different mechanisms – chemical interaction and reaction diffusion, were employed for qualitative explanation of the obtained results.
    Full-text · Article · Jan 2015 · Thin Solid Films
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    ABSTRACT: The possibility of using substrates based on “strained silicon on insulator” structures with a thin (25 nm) buried oxide layer for the growth of light�emitting SiGe structures is studied. It is shown that, in contrast to “strained silicon on insulator” substrates with a thick (hundreds of nanometers) oxide layer, the temperature stability of substrates with a thin oxide is much lower. Methods for the chemical and thermal cleaning of the surface of such substrates, which make it possible to both retain the elastic stresses in the thin Si layer on the oxide and provide cleaning of the surface from contaminating impurities, are perfecte. It is demonstrated that it is possible to use the method of molecular beam epitaxy to grow light emitting SiGe structures of high crystalline quality on such substrates.
    Full-text · Article · Jan 2015 · Semiconductors
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    ABSTRACT: The conditions for producing thin homogeneous mirror-smooth Ge layers on 2-inch Si substrates by means of hot wire chemical vapor deposition (HWCVD) are determined. Ge layers thickness of 200 nm have the structure of epitaxial mosaic single crystal with almost complete relaxation of elastic stresses. Value of X-ray diffraction rocking curve half-width was less 6 '. The density of threading dislocations in the Ge layers was in the range of (3-6) × 105 cm-2, and the value of the root-mean-square surface roughness was less than 0.8 nm.
    Full-text · Article · Jan 2015 · Technical Physics Letters
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    ABSTRACT: Chemical structure of the top Al/C-60 interface in Al/C-60/ITO sandwich structures (Al is the thermally deposited top aluminum layer, C-60 is the thermally deposited fullerene layer, ITO is the double indiumtin oxide, the role of the substrate is played by Lavsan (polyethylene terephthalate), or glass) is studied by time-of-flight secondary mass spectrometry (ToF-SIMS) with depth profiling. The study is stimulated by the recently found specific features of the photovoltaic effect in fullerene-containing sandwich structures on glass or polymer substrates. It is found that the chemical composition of the top Al/C-60 interface is not the same on different substrates. This leads to differences in the photovoltaic conversion parameters for more complex thin-film structures with a molecular heterojunction.
    Full-text · Article · Jan 2015 · Semiconductors
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    ABSTRACT: It is demonstrated using X-ray diffraction and atomic force microscopy that elastic stresses in GeSi layers on Si (115) substrates relax more effectively than in the same layers on Si (001) substrates. This fact is attributed to the predominant contribution of one of the (111) slip planes on the (115) cut. The atomicforce-microscopy image of the GeSi/Si(115) surface reveals unidirectional slip planes, while the GeSi/Si(001) image contains a grid of orthogonal lines and defects at the points of their intersection. As a result, thick GeSi layers on Si (115) have a reduced surface roughness. A technique for calculating the parameters of relaxation of the layer on the Si (115) substrate using X-ray diffraction data is discussed.
    No preview · Article · Jan 2015 · Semiconductors
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    ABSTRACT: Model Al/C60/ITO sandwich devices were fabricated, where Al is a magnetron sputtered aluminum layer (top electrode); C60 is a buckminsterfullerene layer routinely deposited by thermal evaporation in vacuum; and ITO is an indium tin oxide layer (bottom electrode). These devices demonstrate weak rectification in the dark and almost negligible photovoltaic activity under illumination, if polyethyleneterephthalate (PET) is used as substrate. If the substrate is glass, inversion of rectification occurs, accompanied by a rather more pronounced photovoltaic effect (in the reverse direction, too) than in their Al/C60/ITO/PET counterparts. Secondary ion mass spectroscopy (SIMS) with depth-profiling suggests that this effect is associated with the differences in the chemical composition of the top Al/C60 interface in devices on PET and on glass. Such differences result from migration of admixtures from the substrate towards the top electrode. Since (photo)electrical properties of the devices reflect the dominating contribution of one of the two interfaces (top Al/C60 and bottom C60/ITO), rectification can be reversed by amending either interface. This fact is to be taken into account when comparing efficiency of multilayer photovoltaic cells (e.g., with a heterojunction) on different substrates.
    Full-text · Article · Sep 2014 · Synthetic Metals
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    ABSTRACT: Methods for minimizing nonlinear matrix effects in the quantitative determination of germanium concentrations in Gex Si1 − x layers by secondary ion mass spectrometry are discussed. The analysis conditions with positive SiCs+, GeCs+ and negative Ge−, Si− secondary ions produced during sputtering by cesium ions are used in the TOF.SIMS-5 setup with a time-of-flight mass analyzer. In contrast to published works for TOF.SIMS setups, the linear dependence of the ion-concentration ratio Ge−/Si− on x/(1 − x) is shown. Two new linear calibrations for the germanium concentration as a function of the cluster Ge 2− secondary ion yield are proposed. The calibration factors are determined for all linear calibrations at various energies of sputtered cesium ions and Bi+ and probe Bi 3+ ions. It is shown for the first time that the best depth resolution among the possible conditions of quantitative germanium depth profiling in Gex Si1 − x /Si multilayer heterostructures is provided by the calibration mode using elemental Ge− and Si− negative secondary ions.
    No preview · Article · Aug 2014 · Semiconductors
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    ABSTRACT: A new approach to the diagnostics of Gex Si1 − x /Si heterostructures with self-assembled nanoislands, which is based on the method of secondary ion mass spectrometry (SIMS) using secondary Ge2 cluster ions, is discussed. Calibration dependences of the yield of atomic (Ge) and cluster (Ge2) secondary ions on the concentration of germanium in homogeneous Gex Si1 − x have been obtained for a TOF.SIMS-5 setup. It is established that, in contrast to the well-known linear dependence of 74Ge/30Si ∫ x/(1 − x), the secondary Ge2 cluster ions obey the quadratic relation Ge2/30Si ∫ [x/(1 − x)]2. It is shown that the proposed SIMS depth profiling using nonlinear calibration relations for Ge2 cluster ions provides expanded information on multilayer Gex Si1 − x /Si heterostructures with nanoislands. By using this approach, without additional a priori data on the sample structure, it is possible to distinguish planar layers and GeSi layers with three-dimensional nanoislands, estimate the height of islands, reveal the presence of a wetting layer, and trace the evolution of islands during their formation in a multilayer structure.
    No preview · Article · Jul 2014 · Technical Physics Letters
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    D.V. Yurasov · M.N. Drozdov · N.D. Zakharov · A.V. Novikov
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    ABSTRACT: In the present work features of antimony (Sb) segregation in SiGe heterostructures grown by molecular beam epitaxy are investigated. Dependences of the segregation strength on growth temperature, composition and elastic strains are obtained. It is shown that growth conditions and parameters of the structure exert an interrelated impact on the impurity segregation: the influence of the structure parameters depends on growth temperature. Moreover, the alloy composition is found to be a much more significant factor than the elastic strains in SiGe layers. Obtained dependences of Sb segregation on growth conditions and structure parameters were used for formation of selectively doped SiGe heterostructures.
    Full-text · Article · Jun 2014 · Journal of Crystal Growth
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    ABSTRACT: The germanium-distribution profile is investigated in a Si/SiO2/Si structure after the implantation of 74Ge into SiO2 dielectric layer, bonding with the Si device layer, and high-temperature annealing. The anomalously high transport and accumulation of 74Ge atoms near the SiO2/Si interface far from the bonded boundary is found. The observed 74Ge distribution is beyond the framework of the existing model of diffusion of Ge in Si and SiO2 after postimplantation annealing. A modified model of diffusion of Ge atoms near the Si/SiO2 interface qualitatively explaining the observed features is proposed.
    No preview · Article · May 2014 · Semiconductors
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    ABSTRACT: A study of vertical transport in δ-doped SiGe/Si heterostructures is presented. An asymmetrical triple barrier structure was grown with a δ-layer of boron impurity in the center of a narrow quantum well. The growth procedure was followed by conventional processing including photolithography, plasma etching and magnetron sputtering. Secondary-ion mass-spectroscopy depth profiling and high resolution x-ray diffraction were used to control the as-grown structure. The conductance of the structure was measured at liquid helium temperature and analyzed. All pronounced resonances were identified. The resonant feature near 60 mV is attributed to impurity-assisted tunneling, which is supported by calculation of the binding energy of the acceptor in the narrower quantum well.
    Full-text · Article · Mar 2014 · Physica E Low-dimensional Systems and Nanostructures
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    ABSTRACT: A new approach to analyzing the X-ray diffraction spectra of multilayer structures is described. This approach is based on information on the layer growth time. As compared to the standard analysis, the number of variable parameters decreases. The stability and rate of convergence of fitting a calculated spectrum to an experimental spectrum increase in the case of a large number of layers and little-information experimental data. The approach is executed by imposing relations on the model parameters during the calculation of spectra using the Bruker DIFFRAC.Leptos software package. A multilayer SiGe/Si structure is used to compare the new approach and the standard procedure of analysis. The correctness of the new approach is supported by a comparison with the experimental data obtained by secondary-ion mass spectrometry and transmission electron microscopy. The advantages and limitations of the proposed method are discussed.
    Full-text · Article · Feb 2014 · Technical Physics

Publication Stats

346 Citations
102.89 Total Impact Points

Institutions

  • 2014-2015
    • Nizhny Novgorod State University
      Gorkey, Nizjnij Novgorod, Russia
  • 2000-2015
    • Russian Academy of Sciences
      • Institute for Physics of Microstructures
      Moskva, Moscow, Russia
  • 1999-2015
    • Institute for Physics of Microstructures RAS
      Afonino, Nizjnij Novgorod, Russia
  • 2011
    • Novgorod State University
      Nowgorod, Novgorod, Russia