M. N. Drozdov

Institute for Physics of Microstructures RAS, Afonino, Nizjnij Novgorod, Russia

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Publications (129)89.71 Total impact

  • Pavel Andreevich Yunin, Yurii Nikolaevich Drozdov, Mikhail Nikolaevich Drozdov
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    ABSTRACT: We propose a new approach to express SIMS depth profiling on a TOF.SIMS-5 time-of-flight mass spectrometer. The approach is based on the instrument capability to independently perform raster scans of sputter and probe ion beams. The probed area can be much smaller than the diameter of a sputter ion beam, like in the AES depth profiling method. This circumstance alleviates limitations on the sputter beam–raster size relation, which are critical in other types of SIMS, and enables analysis on a curved-bottomed sputter crater. By considerably reducing the raster size, it is possible to increase the depth profiling speed by an order of magnitude without radically degrading the depth resolution. A technique is proposed for successive improvement of depth resolution through profile recovery with account for the developing curvature of the sputtered crater bottom in the probed area. Experimental study of the crater bottom form resulted in implementing a method to include contribution of the instrumental artifacts in a nonstationary depth resolution function within the Hofmann's mixing–roughness–information depth model. The real-structure experiment has shown that the analysis technique combining reduction of a raster size with a successive nonstationary recovery ensures high speed of profiling at ~100 µm/h while maintaining the depth resolution of about 30 nm at a 5 µm depth. Copyright © 2015 John Wiley & Sons, Ltd.
    Surface and Interface Analysis 05/2015; 47(7). DOI:10.1002/sia.5773 · 1.39 Impact Factor
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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).
    Technical Physics Letters 03/2015; 41(3):266-269. DOI:10.1134/S1063785015030189 · 0.58 Impact Factor
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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.
    Thin Solid Films 01/2015; 577. DOI:10.1016/j.tsf.2015.01.025 · 1.87 Impact Factor
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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.
    Technical Physics Letters 01/2015; 41(1). DOI:10.1134/S1063785015010113 · 0.58 Impact Factor
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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.
    Semiconductors 01/2015; 49(1):134-137. DOI:10.1134/S1063782615010261 · 0.71 Impact Factor
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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.
    Semiconductors 01/2015; 49(1):19-22. DOI:10.1134/S1063782615010066 · 0.71 Impact Factor
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    ABSTRACT: Methods for minimizing nonlinear matrix effects in the quantitative determination of germanium concentrations in Ge (x) 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 Ge (x) Si1 - x /Si multilayer heterostructures is provided by the calibration mode using elemental Ge- and Si- negative secondary ions.
    Semiconductors 08/2014; 48(8):1109-1117. DOI:10.1134/S1063782614080090 · 0.71 Impact Factor
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    ABSTRACT: In this work we consider a method of accounting for the nonstationary effects in recovery of SIMS depth profiles. The depth resolution function (DRF) is described by Hofmann's nonstationary MRI (mixing-roughness-information depth) model using the depth-dependent parameters. The effects in question include the nonstationary atomic mixing and development of surface roughness. A mathematical description of the nonstationary depth profiling process by the Fredholm integral equation of the first kind is proposed. The inverse problem is solved using an algorithm based on the Tikhonov regularization method. The proposed nonstationary recovery method is tested on both model and real structures. The development of surface roughness in SIMS depth profiling of the real structure was observed. Grazing incidence x-ray reflectometry (XRR) technique was used to verify the results of SIMS profiles restoration for periodic structure containing thin Ge layers in the Si matrix. The advantages of the proposed recovery algorithm to allow for the nonstationary effects are shown.
    Applied Surface Science 07/2014; 307:33–41. DOI:10.1016/j.apsusc.2014.03.126 · 2.54 Impact Factor
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    ABSTRACT: A new approach to the diagnostics of Ge (x) Si1 - x /Si heterostructures with self-assembled nanoislands, which is based on the method of secondary ion mass spectrometry (SIMS) using secondary Ge-2 cluster ions, is discussed. Calibration dependences of the yield of atomic (Ge) and cluster (Ge-2) secondary ions on the concentration of germanium in homogeneous Ge (x) Si1 - x have been obtained for a TOF.SIMS-5 setup. It is established that, in contrast to the well-known linear dependence of Ge-74/Si-30 a << x/(1 - x), the secondary Ge-2 cluster ions obey the quadratic relation Ge-2/Si-30 a << [x/(1 - x)](2). It is shown that the proposed SIMS depth profiling using nonlinear calibration relations for Ge-2 cluster ions provides expanded information on multilayer Ge (x) 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.
    Technical Physics Letters 07/2014; 40(7):601-605. DOI:10.1134/S1063785014070190 · 0.58 Impact Factor
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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.
    Journal of Crystal Growth 06/2014; 396:66–70. DOI:10.1016/j.jcrysgro.2014.03.042 · 1.69 Impact Factor
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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.
    Semiconductors 05/2014; 48(5):612-616. DOI:10.1134/S1063782614050170 · 0.71 Impact Factor
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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.
    Physica E Low-dimensional Systems and Nanostructures 03/2014; 57:42–46. DOI:10.1016/j.physe.2013.10.022 · 1.86 Impact Factor
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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.
    Technical Physics 02/2014; 59(3):402-406. DOI:10.1134/S1063784214030293 · 0.54 Impact Factor
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    ABSTRACT: A comprehensive study of the crystal structure and distribution of impurities in GaAs nanoheterosystems containing InGaAs quantum wells and delta ‹Mn›-doped layers is performed. High-resolution transmission electronmicroscopy, energy dispersive spectroscopy, and X-ray diffraction are used in particular. It is shown that our technique allows growing structures with embedded delta layers of magnetic impurities epitaxially.
    Bulletin of the Russian Academy of Sciences Physics 01/2014; 78(1):6-8. DOI:10.3103/S1062873814010055
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    ABSTRACT: In this publication, we report the results of studying a multilayerd nonperiodic SiGe/Si structure by the methods of X-ray diffractometry, grazing-angle X-ray reflectometry, and secondary-ion mass spectrometry (SIMS). Special attention is paid to the processing of the component distribution profile using the SIMS method and to consideration of the most significant experimental distortions introduced by this method. A method for processing the measured composition distribution profile with subsequent consideration of the influence of matrix effects, variation in the etching rate, and remnants of ion sputtering is suggested. The results of such processing are compared with a structure model obtained upon combined analysis of X-ray diffractometry and grazing-angle reflectometry data. Good agreement between the results is established. It is shown that the combined use of independent techniques makes it possible to improve the methods of secondary-ion mass spectrometry and grazing-incidence reflectometry as applied to an analysis of multilayered heteroepitaxial structures (to increase the accuracy and informativity of these methods).
    Semiconductors 11/2013; 47(12):1556-1561. DOI:10.1134/S1063782613120221 · 0.71 Impact Factor
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    ABSTRACT: A new variant of depth profiling for thin-film fullerene-containing organic structures by the method of time-of-flight (TOF) secondary ion mass spectrometry (SIMS) on a TOF.SIMS-5 setup is described. The dependence of the yield of C60 molecular ions on the energy of sputtering ions has been revealed and studied. At an energy of sputtering Cs+ ions below 1 keV, the intensity of C60 molecular ions is sufficiently high to make possible both elemental and molecular depth profiling of multicomponent (multilayer) thin-film structures. Promising applications of TOF-SIMS depth profiling for obtaining more detailed information on the real molecular composition of functional organic materials are shown.
    Technical Physics Letters 11/2013; 39(12):1097-1100. DOI:10.1134/S1063785013120183 · 0.58 Impact Factor
  • M. N. Drozdov, A. V. Novikov, D. V. Yurasov
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    ABSTRACT: The effects of the growth temperature, composition, and elastic strains in separate layers on the segregation of antimony are studied experimentally for stressed SiGe structures grown by molecular beam epitaxy. It is established that the growth conditions and parameters of the structures exert an interrelated influence on the segregation of Sb: the degree of the influence of the composition and elastic stresses in the SiGe layers on Sb segregation depends on the growth temperature. It is shown that usage of a method previously proposed by us for the selective doping of silicon structures with consideration for the obtained dependences of Sb segregation on the growth conditions and parameters of the SiGe layers makes it possible to form SiGe structures selectively doped with antimony.
    Semiconductors 11/2013; 47(11):1481-1484. DOI:10.1134/S1063782613110079 · 0.71 Impact Factor
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    ABSTRACT: The results of experimental studies of the effect of rapid thermal annealing on low-barrier diode structures used in the fabrication of microwave detectors for imaging arrays are indicative of an increase in the effective barrier height. Assuming that this effect is related to the diffusion spreading of the silicon δ-doped layer, which determines charge transport in the modified diode, a theoretical model is developed and the diffusion coefficient for silicon in the near-surface region of gallium arsenide (D ≈ 2 × 10−14 cm2/s at 600°C) is estimated. A comparison with published data makes it possible to assume that diffusion in the near-surface layers is greatly facilitated compared to that in the bulk. It is suggested that the cause of acceleration of the diffusion can be a high electric field formed by the charged plane of the detector and it can also be related to an increased density of defects near the surface. The practical result consists in the emerging possibility of increasing (within a certain range) the effective barrier height in the grown structures, which will make it possible to adapt the parameters of low-barrier diodes to the optimal value in order to obtain sensitive detectors.
    Semiconductors 11/2013; 47(11):1470-1474. DOI:10.1134/S106378261311016X · 0.71 Impact Factor
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    ABSTRACT: YBa2Cu3O7 − δ high-temperature superconductor targets subjected to ion-plasma sputtering in a magnetron-sputtering system are studied by X-ray diffraction analysis and secondary ion-mass spectrometry. It is found that dc magnetron sputtering is accompanied by diffusive oxygen depletion and restructuring of the target surface caused by radiation and heat effects of bombarding ions. It is assumed that these changes in the target are responsible for a decrease in the growth rate of YBa2Cu3O7 − δ films.
    Technical Physics Letters 10/2013; 39(10). DOI:10.1134/S1063785013100076 · 0.58 Impact Factor
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    ABSTRACT: Optically transparent hybrid organic–inorganic nanocomposites based on poly(titanium oxide) gels and hydroxyethylmethacrylate (HEMA, with different component ratios, and terpolymers containing lactide or glycolide as a third component) have been synthesized using a two-stage method. Exchange reactions between HEMA and titanium isopropoxide, and hydrolytic polycondensation of titanium alkoxide in the organic monomer agent have been detected. Radical polymerization of HEMA in the presence of poly(titanium oxide) has been studied. The presence of poly(titanium oxide)–oxoethylmethacrylate clusters of 4–6 nm size in the nanocomposites has been established by small-angle X-ray, X-ray phase analysis and secondary ionic mass spectroscopy. The set of physico-mechanical, thermophysical and optical properties of hybrid nanocomposites has been analyzed. Under UV-irradiation of nanocomposites, the single-electron transition Ti4+ Ti3+, accompanied by the darkening/discoloring of the sample, took place. The intensity and speed of photochromic transition can be regulated by changing the composition of nanocomposites. The tensile strength of nanocomposites and the temperature of destruction reach 6.8 MPa and 244 °C respectively. The dependence of the properties of nanocomposites on the initial ratio of organic and inorganic components has been established.
    09/2013; 1(39). DOI:10.1039/C3TC30432A