bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Pseudobinary Alloys (Al2O3)x(TiO2)1 − x as High‐k Dielectrics on Silicon
Authors: Vitanov Petko , Harizanova Antoaneta , Ivanova Tatyana , Alexieva Zvetanka , Ivanova Katya , Agostinelli Guido 
Published: February 2006

AbstractSummary: An interesting opportunity arises when two or more oxides are used as alloys in an attempt to combine the desirable properties of several materials. These systems are predominantly non‐stoichiometric, and in the case of two oxides, they are called pseudobinary alloys. Varying the ratio of the two oxides, thin films with certain preset characteristics can be obtained—refractive index, energy band gap, dielectric constants etc. Our investigations were focussed on spin‐coated (Al2O3)x(TiO2)1 − x films. The electrical properties of (Al2O3)x(TiO2)1 − x were studied forming MIS structures. For accurate determinations of the dielectric constant various measurement methods were used: classical C‐V, impedance spectroscopy and CV map B instrument. The effect of adding Al2O3 to TiO2 is to produce an amorphous dielectric film, which is thermodynamically stable on Si.C‐V curves at 1 MHz of MIS structures with PBA (Al2O3)x(TiO2)1 − x and ALD Al2O3 film.imageC‐V curves at 1 MHz of MIS structures with PBA (Al2O3)x(TiO2)1 − x and ALD Al2O3 film.
Investigation of p‐Type MOS Structure Irradiated with 23 MeV Electrons
Authors: Kaschieva Sonia , Halova Elena , Vlaikova Emilia , Alexandrova Sashka , Valcheva Evgenia , Dmitriev Sergey 
Published: February 2006

AbstractSummary: p‐type silicon MOS structures were irradiated with 23 MeV electrons in vacuum for different durations. Capacitance‐voltage (C/V), current‐voltage (I/V) and conductance‐voltage (G/V) methods were used to investigate the changes in the electrical characteristic of the MOS structures after electron irradiation. Our results show that high‐energy electron irradiation generates positive charges in the oxide and at the SiSiO2 interface, which are frequency dependent. After electron irradiation, two kinds of interface traps are determined. The traps energy position evaluated by these three independent methods is very close to Ev + 0.16 eV and Ev + 0.36 eV. As these results are in a very good agreement with our earlier results, obtained by TSC and DLTS methods, the observed traps can be attributed to the boron‐ (V/B) and oxygen (V/O) vacancies complexes.I/V characteristics of a reference and of a MOS structures, the latter being irradiated by 23 MeV electrons.imageI/V characteristics of a reference and of a MOS structures, the latter being irradiated by 23 MeV electrons.
RBS Investigation of Ion Implanted SiSiO2 Structures Irradiated with 20 MeV Electrons
Authors: Kaschieva Sonia B. , Angelov Christo V. , Dmitriev Sergey N. , Tsutsumanova Gichka I. 
Published: February 2006

AbstractSummary: The influence of high‐energy electron irradiation on the redistribution of silicon and oxygen atoms in implanted SiSiO2 structures has been investigated by Rutherford backscattering spectroscopy (RBS). Two groups of SiSiO2 samples implanted with different doses of silicon ions (1 × 1012 cm−2 and 1 × 1016 cm−2) are used. The ion energy of 15 keV is chosen to produce maximum radiation defects at the SiSiO2 interface. The structures are then irradiated with 20 MeV electrons for different durations (from 60 s up to 120 min). After electron irradiation, the redistribution of the oxygen and silicon atoms in the samples implanted with 1 × 1012 cm−2 Si+ ions is negligible: significant redistribution of these atoms is found only in SiSiO2 samples implanted a with dose of 1016 cm−2. These results demonstrate that the structural changes at the silicon surface of implanted SiSiO2 samples, which take place after electron irradiation, depend more strongly on the implantation dose than on the electron dose irradiation.RBS spectra of SiSiO2 samples implanted with silicon ions and subsequently electron irradiated.imageRBS spectra of SiSiO2 samples implanted with silicon ions and subsequently electron irradiated.
Raman Scattering Characterization of Ion‐Beam Synthesized Mg2Si, 1
Authors: Atanassov Alexander , Zlateva Genoveva , Baleva Mitra , Goranova Ekaterina , Amov Blagoj , Angelov Christo , Mikli Valdek 
Published: February 2006

AbstractSummary: The unpolarized Raman scattering spectra of ion beam synthesized Mg2Si phase, embedded in (100) Si matrix are studied. We used two different doses for the Mg ions, 4 × 1017 cm−2 and 8 × 1017 cm−2, each of them with two different energies 40 keV and 60 keV, which were implanted into (100) Si substrates. After implantation, the samples were subjected to rapid thermal annealing for different durations. The samples' surfaces were studied by scanning electron microscopy (SEM). On the basis of the Raman spectra behavior, conclusions were drawn about the influence of the technological parameters on the formation of the Mg2Si phase.SEM microphotographs of samples produced with an ion dose of 8 × 1017 cm−2, an ion energy of 40 keV, and annealed for 60 s.imageSEM microphotographs of samples produced with an ion dose of 8 × 1017 cm−2, an ion energy of 40 keV, and annealed for 60 s.
Influence of the Implantation Dose and of the Annealing Duration on the Raman Spectra of Ion‐Beam Synthesized β‐FeSi2 Layers
Authors: Marinova Maya , Zlateva Genoveva , Baleva Mitra 
Published: February 2006

AbstractSummary: The samples under investigation are prepared by ion‐beam synthesis, followed by rapid thermal annealing. Fe ions with two different doses, each of them with two different energies, are implanted into Si substrates. The two step implantation with the iron doses used ensure the formation of unburied polycrystalline continuous β‐FeSi2 layers with a thickness of about 50 nm in the case of the lowest implantation dose, and of about 100 nm in the case of the higher one. We observed the same Raman modes, which are predicted theoretically and detected experimentally by other authors as well. The influence of the Fe ion dose and of the annealing time on the Raman spectra behavior is characterized.Raman spectra of a sample obtained by implantation with 5 × 1016 cm−2 dose of iron ions, and annealed at 900 °C for 60 s.imageRaman spectra of a sample obtained by implantation with 5 × 1016 cm−2 dose of iron ions, and annealed at 900 °C for 60 s.
Electron Energy Distribution Function Measurements in an Inductively Driven Tandem Plasma Source
Authors: Tsankov Tsanko , Kiss'ovski Zhivko , Djermanova Nina , Kolev Stanimir 
Published: February 2006

AbstractSummary: Electron energy distribution functions (EEDF) are obtained from probe measurement data along the axis of the metallic chamber of an inductively driven tandem plasma source. The numerical procedure for calculating the second derivative of the probe current combines Savitzky‐Golay smoothing filter and the three‐point differentiator with a varying step. The EEDF is obtained through the Druyvesteyn formula from the calculated second derivative. The shape of the EEDFs in argon gas at low pressures is investigated for the case of a tandem plasma source. Experimental EEDFs are compared with Maxwellian distributions, and deviations in the tail are observed at higher pressures, which are explained in terms of the ratio between the electron‐electron collision frequency and the excitation frequency. Axial variations of the slope and of the area below the EEDF curve result in electron temperature and concentration decrease along the axis.Electron energy distribution function (EEDF) measured for gas pressure of 26 mTorr, at an axial position of 12 cm.imageElectron energy distribution function (EEDF) measured for gas pressure of 26 mTorr, at an axial position of 12 cm.
Spatial Distribution of the Wave Field of Filamented High‐Frequency Discharges
Authors: Lishev Stiliyan , Schlüter Hans , Shivarova Antonia , Tarnev Khristo 
Published: February 2006

AbstractSummary: This study is on high pressure surface wave‐sustained discharges at the stage of their contraction into filaments: gas discharge channels positioned in the off‐center region of the cross section of the discharge and extended along its length. Based on results for the dispersion behavior and the space distribution of the wave field, obtained by a 2D numerical code developed for describing surface wave properties in plasma with an arbitrary distribution of density, the structure of the modes sustaining the discharge was identified. It is reminiscent of the superposition of an azimuthally‐symmetric and azimuthally‐asymmetric field configurations. The results obtained form the basis for modelling the plasma behavior in the discharge.Space distribution of the amplitude of the Ez field component of a surface wave sustaining a dipole filamentary structure.imageSpace distribution of the amplitude of the Ez field component of a surface wave sustaining a dipole filamentary structure.
Fabrication and Study of Periodically Structured Y2O3 Waveguides
Authors: Dikovska Anna Og. , Tonchev Svetlen H. , Vasilev Cvetelin , Atanasov Petar A. 
Published: February 2006

AbstractSummary: Periodically structured waveguides have several advantages over their unstructured‐planar film counterparts such as lower threshold for laser generation, due to the lateral confinement of both the pump and the laser modes, higher coupling efficiency, and easy operation. The structural and optical qualities of the waveguides, on the one hand, and the diffraction efficiency of the periodic structure, on the other, are the key parameters that must be controlled in order to obtain planar waveguides suitable for laser application. In the present work, thin Er, Yb‐doped Y2O3 films were grown on a periodically structured glass substrate by laser ablation. The waveguide structure has a period of 560 nm. The smooth surface, good adhesion, and possibility to repeat the substrate structure make the deposition method suitable for preparation of structured waveguides. The waveguide thickness non‐uniformity introduced by the laser deposition method was estimated to be about 4.6%. It does not affect the waveguide propagation.AFM image of the surface after deposition of the waveguide.imageAFM image of the surface after deposition of the waveguide.
Laser Heterodyne Measurement of Photothermal Displacement for Material Surface Characterization
Authors: Pencheva Vasilka , Penchev Stoyan , Naboko Vasilii , Donchev Todor , Kolev Svetoslav , Kutzarova Tania 
Published: February 2006

AbstractSummary: Double‐heterodyne photodisplacement technique (PDT), based on the detection of the thermal expansion of a sample under irradiation by laser light has been employed to improve the resolution of photothermal displacement measurements up to orders of sub‐picometers. We have developed an ultra‐sensitive system to measure photothermal displacement of metallic and non‐metallic materials, such as silicon, due to the illumination by an ordinary laser diode. Non‐destructive characteristics of the scheme are well suited for conditions that restrict access to the sample to be measured. Careful consideration is given to eliminate the noise sources, so as to achieve the level of sensitivity that needed to detect the structural inhomogeneity of materials. Good agreement between experimental results and theoretical predictions is demonstrated.Laser double‐heterodyne detection of the photo‐thermal expansion of metallic and non‐metallic materials illuminated by a laser diode.imageLaser double‐heterodyne detection of the photo‐thermal expansion of metallic and non‐metallic materials illuminated by a laser diode.
Electrical and Optical Characteristics of Ta2O5 Thin Films Deposited by Electron‐Beam Vapor Deposition
Authors: Todorova Zhana , Donkov Nikolay , Ristić Zoran , Bundaleski Nenad , Petrović Suzana , Petkov Mario 
Published: February 2006

AbstractSummary: Ta2O5 is a material with good perspectives for many applications in modern electronics and information technologies. Several deposition techniques of thin Ta2O5 films have been suggested. Reliable information is still needed, however, on structural, electrical and optical parameters of the films, and their dependence on the deposition technique. We have deposited Ta2O5 thin films by electron‐beam evaporation of Ta2O5 powder onto Si, tantalum and glass substrates. The resistivity of the films with various thicknesses was measured by four‐point probe method before and after annealing in an oxygen atmosphere. The reflectance in the IR region depending on the substrate and film thickness was shown.IR characteristics of the 320 nm thick films deposited on glass substrates after annealing.imageIR characteristics of the 320 nm thick films deposited on glass substrates after annealing.
Detection of NH3 by Quartz Crystal Microbalance Coated with Ta2O5
Authors: Georgieva Velichka , Spassov Lozan , Donkov Nikolay , Petkov Plamen , Atanassov Mitko 
Published: February 2006

AbstractSummary: This paper reports a study of the sorption properties of thin Ta2O5 films to NH3 vapors. The films are deposited using electron beam evaporation. In order to determine the sorption ability of Ta2O5 to NH3, a quartz crystal microbalance (QCM) with a thin Ta2O5 film is investigated. The Ta2O5 film is used as a receptor for the NH3 gas. The AT‐cut, 14 MHz quartz resonators allow conversion of the additional mass loading that occurs as a result of sorption into a frequency shift. The experiments are carried out by measuring the resonant frequency shift of the QCM to vapors from an aqueous solution of NH3 with different concentrations from 10 to 10 000 ppm. The obtained experimental results indicate that the variations of the resonant frequency are a function of the ammonia concentration and the thickness of the Ta2O5 layer. The process of sorption is found to be reversible. The reported investigation shows that a QCM covered with a thin Ta2O5 layer is sensitive to ammonia vapors at room temperature and is able to detect NH3 concentrations in the investigated range (10–10 000 ppm).Relative change of QCM frequency versus ammonia concentrationimageRelative change of QCM frequency versus ammonia concentration
Determination of Nitrogen Atoms Loss Probabilities on Copper, Aluminium, Alumina, Brass and Nylon Surfaces
Authors: Sarrette Jean‐Philippe , Rouffet Benoît , Ricard André 
Published: February 2006

AbstractSummary: Materials exposure to a flowing post discharge jet can induce a significant rise of materials temperature. This increase is related to the recombination of the atomic species produced in the discharge at the surface of the exposed materials, which is a highly exothermic process. At pressures below 10 Torr, this process is the main loss term for the atoms far away from the discharge. Nevertheless, a very small number of reliable data concerning atomic recombination probabilities, γ, is available in the literature. In this work, such data are obtained for the recombination of the nitrogen atoms on five materials (copper, aluminium, alumina, brass and Nylon) by the adjustment between measured surface temperatures and calculated values obtained by a 3D modelling of the post discharge reactor, which includes the enthalpy deposition at the walls. Results show a general decrease of the γ‐values with increasing pressure, as already mentioned by other authors. The sensitivity of the method is also studied.Evolution with pressure of the N‐atom recombination probability γN for aluminium, copper, brass, alumina and Nylon.imageEvolution with pressure of the N‐atom recombination probability γN for aluminium, copper, brass, alumina and Nylon.
PIC – MCC Numerical Simulation of a DC Planar Magnetron
Authors: Kolev Ivan , Bogaerts Annemie 
Published: February 2006

AbstractSummary: A 2d3v numerical model of a DC sputter magnetron is presented. The model is fully self‐consistent and kinetic. Based on the Particle‐in‐Cell/Monte Carlo Collisions technique it includes modules for the gas heating and the diffusion transport of the sputtered atoms. An external electric circuit is incorporated to achieve the calculation of the cathode voltage in a self‐consistent manner, as well as the simulation of the constant current regime. The model is applied to a laboratory magnetron operated in argon.Calculated distribution of the electric potential, V, at p = 10 mTorr. The white line corresponds to V = 0 V.imageCalculated distribution of the electric potential, V, at p = 10 mTorr. The white line corresponds to V = 0 V.
Spectroscopic Ellipsometry as a Tool for Damage Profiling in Very Shallow Implanted Silicon
Authors: Karmakov Iordan , Konova Anka , Chakarov Ivan 
Published: February 2006

AbstractSummary: Ion implantation is still one of the key steps in Si integrated circuit technology. Spectroscopic Ellipsometry (SE) detects the defects created in the implanted Si. The successful application of SE for damage profiling depends on the quality of the algorithm used for evaluating the damage profile from SE data. In this work, we present retrieved SE damage depth profiles by our previously published algorithm in the as‐implanted Si with very low energies Ge+ ions‐ from 2 keV to 20 keV and 1 keV B+ ions (1 × 1015 cm−2). The comparisons of the SE retrieved damage depth profiles with experimental atomic concentration depth profiles, or simulated by the state‐of‐the‐art computer ATHENA code of Silvaco TCAD suits were made. The functional relation was obtained by proper fitting of measured by SE a/c depths, and the depths named “ends of damage” with the experimental or simulated ions concentration depth profiles. For reasons not understood, the damage profile of 5 keV Ge+ in c‐Si is smoother in shape beyond the a/c depth, with a longer tail.The damage profiles measured by SE for 5 keV Ge+ in c‐Si with two different doses: curve 1 ‐ for 6 × 1013 cm−2 and curve 2 ‐ for 1 × 1015 cm−2. Curve 3 ‐ presents the damage profile simulated by ATHENA for Ge+ ions with 5 keV; 1 × 1015 cm−2.imageThe damage profiles measured by SE for 5 keV Ge+ in c‐Si with two different doses: curve 1 ‐ for 6 × 1013 cm−2 and curve 2 ‐ for 1 × 1015 cm−2. Curve 3 ‐ presents the damage profile simulated by ATHENA for Ge+ ions with 5 keV; 1 × 1015 cm−2.
EHD Ponderomotive Forces and Aerodynamic Flow Control Using Plasma Actuators
Authors: Pinheiro Mario J. 
Published: February 2006

AbstractSummary: We present a self‐consistent two‐dimensional fluid model of the temporal and spatial development of the one atmosphere uniform glow discharge plasma (OAUGDP®). Continuity equations for electrically charged species N, N, O, O, and electrons are solved coupled to the Poisson equation, subject to appropriate boundary conditions. An algorithm proposed by Patankar was used (S. V. Patankar, “Numerical Heat Transfer and Fluid Flow”, Taylor Francis, New York 1980). The transport parameters and rate coefficients for electrons at atmospheric pressure are obtained by solving the homogeneous Boltzmann equation for electrons under the hydrodynamic assumption. Operational variables are obtained as a function of time: electric current; surface charge accumulated on the dielectric surface; the memory voltage and the gas voltage controlling the discharge. The spatial distribution of the electric field, the populations of charged species, the resulting ponderomotive forces, and the gas speed are also obtained.Schematic representation of electrode geometry of an energized OAUGD® plasma panel.imageSchematic representation of electrode geometry of an energized OAUGD® plasma panel.
Growth and Modification of Organosilicon Films in PECVD and Remote Afterglow Reactors
Authors: Supiot Philippe , Vivien Céline , Granier Agnès , Bousquet Angélique , Mackova Anna , Escaich David , Clergereaux Richard , Raynaud Patrice , Stryhal Zdenek , Pavlik Jaroslav 
Published: February 2006

AbstractSummary: Five hundred nanometer thick organosilicon coatings are prepared on Si substrates in parallel by the plasma‐assisted polymerisation of hexamethyldisiloxane (HMDSO) in an RF‐inductively coupled plasma (RFICP) and distributed electron cyclotron resonance plasma (DECRP) at low pressure (0.27 Pa) and of tetramethyldisiloxane (TMDSO) premixed with oxygen in an N2 microwave induced remote afterglow (MIRA) at 560 Pa. The structure of these different films is analyzed by different techniques, such as Fourier‐transform infrared spectroscopy, Rutherford backscattering spectrometry, atomic force microscopy, ellipsometry, and contact angle measurements. Results of the film composition (at least 30% carbon content), optical properties, and morphology indicate a low cross‐linking degree accompanied by short chain length for RFICP and DECRP films, in contrast to a high‐molecular‐weight structure observed for the MIRA film. Carbon removal is achieved within the same plasma reactors by further oxygen‐containing plasma treatment performed in the RF‐ICP (3.33 Pa), DECRP (0.27 Pa, −200 V biased substrate), and MIRA (N2/O2 (98.7:1.3, 560 Pa)) reactors. The same measurements are carried out on the treated samples in order to detect the main changes in film composition, optical properties, and morphology. The evolution of surface energy is also studied. The results are discussed according to film structure and process specificity.O/Si and C/Si elemental ratios calculated from RBS analysis for an as‐deposited RF‐inductively coupled plasma coating (RFICP) and films post‐treated by N2/O2 microwave induced remote afterglow (MIRA), O2 RFICP and O2 distributed electron cyclotron resonance plasma (DECRP, biased sample) processes.imageO/Si and C/Si elemental ratios calculated from RBS analysis for an as‐deposited RF‐inductively coupled plasma coating (RFICP) and films post‐treated by N2/O2 microwave induced remote afterglow (MIRA), O2 RFICP and O2 distributed electron cyclotron resonance plasma (DECRP, biased sample) processes.
Raman Scattering Characterization of Ion‐Beam Synthesized Mg2Si, 2
Authors: Zlateva Genoveva , Atanassov Alexander , Baleva Mitra , Nicolova Lora 
Published: February 2006

AbstractSummary: The polarized Raman spectra of ion‐beam synthesized Mg2Si, embedded in (001) and (111) Si substrates were studied. The relative intensities of the F2g mode measured in several exact scattering configurations are compared with those calculated under the condition for minimum mismatch between the Si and Mg2Si lattices. A conclusion for the orientational growth of the Mg2Si phase in Si is drawn.The matching of the (111) Si and (111) Mg2Si planes.imageThe matching of the (111) Si and (111) Mg2Si planes.