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1.
A. E. Dolbak B. Z. Ol’shanetskii S. A. Tiis R. A. Zhachuk 《Physics of the Solid State》1999,41(8):1364-1368
The effect of the coadsorption of Co and Ni on an Si(111) surface structure and on the diffusion of adsorbed atoms is investigated
by low-energy electron diffraction and Auger electron spectroscopy. It is established that surface structures similar to those
formed with the adsorption of Co alone are formed with the Ni and Co coadsorption on an Si(111) surface. It is found that
the contribution of surface diffusion to the transport of Ni atoms is sharply higher on an Si(111) surface with submonolayer
Co concentrations in the temperature range 500–750 °C than for a pure surface, where the main mechanism of Ni transport along
the surface is diffusion of Ni atoms through the bulk of Si.
Fiz. Tverd. Tela (St. Petersburg) 41, 1489–1494 (August 1999) 相似文献
2.
Qualitative changes are observed in the character of the surface electronic structure accompanying the adsorption of potassium
on a Si(111) 7×7 surface. The metallic conductivity of the Si(111)7×7 surface is destroyed at the very early stages of adsorption.
A new band induced by the adsorption of potassium is observed below the Fermi level. It is found that the K/Si(111)7×7 interface
is semiconducting right up to saturating coverage. A surface transition from an insulating into a metallic state, accompanied
by pinning of the Fermi level, is observed in the region of saturating coverage. Metallic conductivity arises in the adsorbed
potassium layer as a result of the development of an induced surface band at the Fermi level.
Pis’ma Zh. éksp. Teor. Fiz. 66, No. 1, 27–30 (10 July 1997) 相似文献
3.
The mechanism of the transport of nickel along a Si(111) surface in the presence of adsorbed cobalt atoms is established by
LEED and Auger electronic spectroscopy. The mechanism consists of diffusion of nickel atoms through the bulk and segregation
of the atoms on the surface during annealing. This mechanism of nickel transport plays the governing role at temperatures
below 700°C, where nickel transport along clean silicon surfaces is not observed. It is found that the nickel segregation
factor is what determines the lowest temperature at which nickel transport is observed on clean silicon surfaces.
Pis’ma Zh. éksp. Teor. Fiz. 69, No. 6, 423–425 (25 March 1999) 相似文献
4.
Continuing miniaturization of electronic devices necessarily requires assembly of several different objects or devices in
a small space. Therefore, besides thin films growth, the possibility of fabricating wires and dots [1, 2] at the nanometre
scale composed of metal silicides is of the top interest. This report is about the STM/STS investigation of cobalt silicides’
nanostructures created on Si(111)-(√19 × √19) substrates via Co evaporation and post deposition annealing. This (√19 × √19)
reconstruction was induced by Ni doping. Less than 1ML of Co on surface was obtained. Surface reconstruction induced growth
of agglomerates of clusters rather than an uniform layer. The post deposition annealing of a crystal sample (up to 670 K,
770 K, 870 K, 970 K, 1070 K and 1170 K) led to creation of silicides’ nanostructures. Measurements showed that coalescence
of Co nanoislands begun around 970 K. Annealing above 1070 K led to alloying of a Co, Ni and Si. As a consequence the Si(111)-(7×7)
reconstruction occurred at the cost of Si(111)-(√19 × √19).
相似文献
5.
U. Höfer 《Applied Physics A: Materials Science & Processing》1996,63(6):533-547
Optical second-harmonic generation (SHG) from silicon surfaces may be resonantly enhanced by dangling-bond-derived surface states. The resulting high sensitivity to hydrogen adsorption combined with unique features of SHG as an optical probe has been exploited to study various kinetical and dynamical aspects of the adsorption system H2/Si. Studies of surface diffusion of H/Si(111)7×7 and recombinative desorption of hydrogen from Si(111)7 × 7 and Si(100)2 × 1 revealed that the covalent nature of hydrogen bonding on silicon surfaces leads to high diffusion barriers and to desorption kinetics that strongly depend on the surface structure. Recently, dissociative adsorption of molecular hydrogen on Si(100)2×1 and Si(111)7×7 could be observed for the first time by heating the surfaces to temperatures between 550 K and 1050 K and monitoring the SH response during exposure to a high flux of H2 or D2. The measured initial sticking coefficients for a gas temperature of 300K range from 10–9 to 10–5 and strongly increase as a function of surface temperature. These results demonstrate that the lattice degrees of freedom may play a decisive role in the reaction dynamics on semiconductor surfaces. 相似文献
6.
A. I. Oreshkin R. Z. Bakhtizin P. Murugan V. Kumar N. Fukui T. Hashizume T. Sakurai 《JETP Letters》2010,92(7):449-452
Spatially resolved images of an individual C60F18 fluorofullerene molecule on Si(100) − 2 × 1 surface have been obtained using scanning tunneling microscopy. Scanning tunneling
microscopy results and ab initio calculations show that the fluorofullerene molecules interact with the Si(100) − 2 × 1 surface
with F atoms pointing down towards the surface. The adsorption energy of a C60F18 molecule on Si(100) − 2 × 1 surface is ∼12.1 eV, which is much higher than the adsorption energy of the same molecule on
Si(111) − 7 × 7 surface (6.65 eV). C60F18 molecules are located in the troughs in-between the dimer rows occupying the four-dimer site on Si(100) − 2 × 1 surface. 相似文献
7.
Anupam Roy Trilochan Bagarti K. Bhattacharjee K. Kundu B.N. Dev 《Surface science》2012,606(9-10):777-783
Ge atoms have been deposited on domain-patterned clean Si(111)-(7 × 7) and oxidized Si(111)-(7 × 7) surfaces. Clustering of Ge from the deposited Ge adatoms on these two kinds of surfaces shows contrasting patterns. On the clean Si surface, clustering predominantly occurs on domain boundaries, which include step edges on two sides. This leaves small domains denuded. Ge diffusion length has been estimated from the size of these denuded domains. For large domains, additional clustering is observed within the domains. For the oxidized Si surface, the pattern formation is in sharp contrast with that for the clean Si surface. In this case the domain boundaries remain relatively empty and there is strong clustering within the domains leading to the formation of dense Ge nanoislands within the domains. This contrasting pattern formation has been explained via a reaction diffusion model. 相似文献
8.
The surface structures 3 × 2, 5 × 2, 7 × 2, and 9 × 2 formed on the Si(111) plane during adsorption of submonolayer strontium
have been investigated using scanning tunneling microscopy. The experimental data obtained are in agreement with the models
of surface reconstructions proposed earlier for the structures induced by the adsorption of divalent metal atoms. An important
constituent of these structures is provided by strontium atomic chains in the 〈1$
\bar 1
$
\bar 1
0〉 direction. Three types of domains of surface structures are formed on the Si(111) plane, which correspond to the rotational
symmetry C
3 of the surface under consideration. The reduction of the symmetry of the substrate to C
1 with the use of the stepped Si(7 7 10) surface makes it possible to form strontium atomic chains, which are oriented with
respect to the substrate in a similar manner. 相似文献
9.
A. V. Dvurechenskii V. A. Zinov’ev V. A. Markov 《Journal of Experimental and Theoretical Physics》1998,87(6):1116-1121
Reflected high-energy electron diffraction (RHEED) and detection of the intensity oscillations of the specular reflection
have been used to investigate morphological changes in Si(111) associated with the two-dimensional layer-by-layer mechanism
of silicon growth from a molecular beam under conditions of pulsed (0.25–1 s) bombardment with low-energy (80–150 eV) Kr ions
in the interval of small total radiative fluxes (1011–1012 cm22), for which the density of radiation-generated defects is small in comparison with the surface density of the atoms. After
pulsed ion bombardment an increase in the intensity of the specular reflection is observed if the degree of filling of the
monolayer satisfies 0.5<θ<1. No increase in the intensity occurs during the initial stages of filling of the monolayer. The maximum amplitude increment
of the oscillations is reached at θ≈0.8. The magnitude of the amplitude increment of the RHEED oscillations increases with temperature up to 400°C and then falls.
At temperatures above 500°C amplification of the reflection intensity essentially vanishes. Experiments on multiple ion bombardment
of each growing layer showed that the magnitude of the amplitude increment of the oscillations decreased as a function of
the number of deposited layers (the order of the RHEED oscillation). A mechanism for the observed phenomena is proposed, based
on the concept of surface reconstruction by pulsed ion bombardment accompanied by formation of a (7×7) superstructure, which
corresponds to a decrease of the activation energy of surface diffusion of the adatoms. Within the framework of the proposed
mechanism the results of Monte Carlo modeling agree with the main experimental data.
Zh. éksp. Teor. Fiz. 114, 2055–2064 (December 1998) 相似文献
10.
Oleksandr Romanyuk Keita Kataoka Fumihiko Matsui Ken Hattori Hiroshi Daimon 《Czechoslovak Journal of Physics》2006,56(3):267-276
The atomic structure of thin iron silicide film, grown epitaxially on the Si(111) surface, has been analyzed by means of the
three-dimensional RHEED Patterson function analysis. The iron-silicide-terminated surface with (2 × 2) periodicity has been
prepared by a solid-phase epitaxy method. 2 ML of Fe were deposited on the Si(111)-(7 × 7) surface and annealed at 500°C.
Three-dimensional Patterson function was calculated from series of φ-scanned RHEED intensity distributions converted to the k-space. The resulting model of γ-FeSi2 structure consists of two silicide layers faulted to each other with three relaxed Si adatoms above the H3 site. 相似文献
11.
The mechanism of silicon epitaxy on porous Si(111) layers is investigated by the Monte Carlo method. The Gilmer model of adatom
diffusion extended to the case of arbitrary surface morphology is used. Vacancies and pendants of atoms are allowed in the
generalized model, the activation energy of a diffusion hop depends on the state of the neighboring positions in the first
and second coordination spheres, and neighbors located outside the growing elementary layer are also taken into account. It
is shown that in this model epitaxy occurs by the formation of metastable nucleation centers at the edges of pores, followed
by growth of the nucleation centers along the perimeter and the formation of a thin, continuous pendant layer. Three-dimensional
images of surface layers at different stages of epitaxy were obtained. The dependence of the kinetics of the epitaxy process
on the amount of deposited silicon is determined for different substrate porosities.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 7, 512–517 (10 April 1998) 相似文献
12.
R. A. Zhachuk S. A. Teys B. Z. Olshanetsky 《Journal of Experimental and Theoretical Physics》2011,113(6):972-982
The diffusion of strontium atoms on the Si(111) surface at room temperature has been investigated using scanning tunnel microscopy
and simulation carried out in terms of the density functional theory and the Monte Carlo method. It has been found that the
reconstruction of a clean silicon surface with a 7 × 7 structure has a profound effect on the diffusion process. The average
velocity of motion of a strontium atom in a unit cell of the 7 × 7 structure has been calculated. The main diffusion paths
of a strontium atom and the corresponding activation energies have been determined. It has been demonstrated that the formation
of scanning tunnel microscope images of the Si(111)-7 × 7 surface with adsorbed strontium atoms is significantly affected
by the shift of the electron density from the strontium atom to the nearest neighbor silicon adatoms in the 7 × 7 structure. 相似文献
13.
2 and Si lattices at 380 °C, which was defined as zero-mismatch temperature. The implantation was conducted with a metal vapor
vacuum arc (MEVVA) ion implanter at an extraction voltage of 45 kV. Based on a thermal conduction estimation, a temperature
rise of 380 °C required the Ni-ion current density to be 35 μA/cm2. For the Si(111) wafers, the high conducting NiSi2 layers were indeed directly formed after Ni-ion implantation with this specific current density to a normal dose of 2×1017 ions/cm2 and the resistivity was as low as 9 μΩ cm. For the Si(111) wafers pre-covered with a 10-nm Ni overlayer, the resistivity
of the NiSi2 layers obtained under the same conditions decreased down to about 6 μΩ cm. The superior electrical property of the NiSi2 was thought to be related to its formation temperature, i.e. at a zero-mismatch temperature of 380 °C, which resulted in
minimizing the stress and stress-induced defects involved in its formation as well as cooling process.
Received: 27 April 1998 / Accepted: 26 October 1998 相似文献
14.
S. A. Teys E. M. Trukhanov A. S. Ilin A. V. Kolesnikov 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(8):1055-1058
The surface phase transitions 7 × 7 → 5 × 5 for two-dimensional and c2 × 8 →7 × 7 and 7 × 7 → c2 × 8 for three-dimensional Ge islands epitaxially grown on Si(111) were found experimentally using scan- ning tunneling microscopy.
The first two transitions are associated with an increase in the level of misfit strains, while the last is related to a decrease
in the stress level during plastic relaxation. 相似文献
15.
Effects of pulsed irradiation by low-energy ions during homoepitaxy of silicon from a molecular beam
A. V. Dvurechenskii V. A. Zinov’ev V. A. Markov R. Crötzchel K. -X. Heinig 《JETP Letters》1996,64(10):742-747
The change in the morphology of a Si(111) surface under pulsed irradiation by 145-eV Kr+ ions with a pulse duration of 0.5 s during epitaxy of silicon from a molecular beam is studied experimentally by RHEED. It
is found that pulsed irradiation by low-energy ions intensifies the specular reflection. This corresponds to a decrease in
the roughness of the growing surface. It is shown that the observed effect depends strongly on the degree of filling of the
surface atomic layer, the substrate temperature, and the ion current density.
Pis’ma Zh. éksp. Teor. Fiz. 64, No. 10, 689–694 (25 November 1996) 相似文献
16.
Z. Chvoj Z. Chromcová V. Cháb 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,76(3):453-461
In this article we investigate the complex 1D mesoscopic model of adatom diffusion and the evolution of an ordered phase on
the substrate surface. The analysis of the theoretical model is compared with the experimental results of the spreading of
Au
adatoms on Si(111)-(7×7) surface. The steady state solutions and their stability conditions are determined within the concept
of the traveling-wave solution. It is shown that the formation of the ordered
phase (5×2) and the difference in the diffusion of Au on (7×7) and on (5×2) structure results in a sharp edge of diffusion
front which corresponds to the coverage of a saturated
(5×2) phase. This edge moves linearly in time and α can be determined by experiment. The system of model equations enables
the damped waves solution or temporary evolution of two steps. 相似文献
17.
Role of buried ultra thin interlayer silicide on the growth of Ni film on Si(100) substrate 总被引:1,自引:0,他引:1
D.K. Sarkar M. Falke H. Giesler S. Teichert G. Beddies H.-J. Hinneberg 《Applied Physics A: Materials Science & Processing》2000,70(6):681-684
The presence of a buried, ultra-thin amorphous interlayer in the interface of room temperature deposited Ni film with a crystalline
Si(100) substrate has been observed using cross sectional transmission electron microscopy (XTEM). The electron density of
the interlayer silicide is found to be 2.02 e/?3 by specular X-ray reflectivity (XRR) measurements. X-ray diffraction (XRD) is used to investigate the growth of deposited
Ni film on the buried ultra-thin silicide layer. The Ni film is found to be highly textured in an Ni(111) plane. The enthalpy
of formation of the Ni/Si system is calculated using Miedema’s model to explain the role of amorphous interlayer silicide
on the growth of textured Ni film. The local temperature of the interlayer silicide is calculated using enthalpy of formation
and the average heat capacity of Ni and Si. The local temperature is around 1042 K if the interlayer compound is Ni3Si and the local temperature is 1389 K if the interlayer compound is Ni2Si. The surface mobility of the further deposited Ni atoms is enhanced due to the local temperature rise of the amorphous
interlayer and produced highly textured Ni film.
Received: 2 March 2000 / Accepted: 28 March 2000 / Published online: 11 May 2000 相似文献
18.
P.G. Karlsson J.H. Richter M.P. Andersson M.K.-J. Johansson J. Blomquist P. Uvdal A. Sandell 《Surface science》2011,605(13-14):1147-1156
The interaction between the metal organic precursor molecule titanium(IV) isopropoxide (TTIP) and three different surfaces has been studied: Si(111)-(7 × 7), SiOx/Si(111) and TiO2. These surfaces represent the different surface compositions encountered during TTIP mediated TiO2 chemical vapor deposition on Si(111). The surface chemistry of the titanium(IV) isopropoxide precursor and the film growth have been explored by core level photoelectron spectroscopy and x-ray absorption spectroscopy using synchrotron radiation. The resulting film morphology has been imaged with scanning tunneling microscopy. The growth rate depends on both surface temperature and surface composition. The behavior can be rationalized in terms of the surface stability of isopropoxy and isopropyl groups, confirming that growth at 573 K is a reaction limited process. 相似文献
19.
Andrey E. Dolbak Ruslan A. Zhachuk Boris Z. Olshanetsky 《Central European Journal of Physics》2004,2(2):254-265
Pb diffusion on clean Si(111), (100), and (110) surfaces was studied by Auger electron spectroscopy and low energy electron
diffraction in the temperature range from 100 to 300°C. It is shown that lead transport along sillicon surfaces takes place
via the mechanism of solid-phase spreading with a sharp moving boundary. The temperature dependence of the Pb diffusion coefficients
on Si(111), (100) and (110) surfaces have been obtained. A Si(110)-4×2-Pb surface structure has been observed for the first
time. 相似文献
20.
A. Yu. Grigor’ev A. M. Shikin G. V. Prudnikova S. A. Gorovikov V. K. Adamchuk 《Physics of the Solid State》1998,40(3):519-523
Formation of the Eu/Si(111) system as the metal layer thickness gradually increases from 0.5 to 60 monolayers (ML) deposited
on the silicon surface at room temperature, and after heating at up to 900 °C, has been studied by Auger electron spectroscopy,
electron-energy-loss spectroscopy, and low-energy-electron diffraction. It is shown that room-temperature film growth passes
through three stages, depending on the Eu layer thickness: metal chemisorption, interdiffusion of the metal and substrate
atoms, and buildup of the metal on the surface of the system. Heating of ultrathin (about one ML) Eu films deposited at room
temperature results in ordering of metal atoms on the silicon surface with only weak interaction. Heating thick (above 15
ML) Eu layers on the silicon surface produces silicides whose structure depends on the heating temperature.
Fiz. Tverd. Tela (St. Petersburg) 40, 562–567 (March 1998) 相似文献