共查询到20条相似文献,搜索用时 15 毫秒
1.
N. A. Vlasenko P. F. Oleksenko Z. L. Denisova N. V. Sopinskii L. I. Veligura E. G. Gule O. S. Litvin M. A. Mukhlyo 《Semiconductors》2011,45(5):587-592
The spectrum of the photoconductivity induced by the polarization field of charges at surface states and traps in the film
bulk has been analyzed to determine the energy band diagram at the c-Si-SiO
x
interface and the changes in the electronic states after the film annealing. It is found that the energy bands are bent at
the Si-SiO
x
interface and the Si surface is enriched in electrons. In equilibrium the photocurrent peak at 1.1 eV is due to the band-to-band
transitions in the silicon part of the interface. Annealing shifts the peak to higher energies; this shift increases with
an increase in the annealing temperature from 650 to 1000°C. This effect is accompanied by a decrease in the photocurrent
at ≤1.1 eV and weakening of the band-edge photoluminescence near the Si surface. The changes revealed are explained by the
formation of an oxide layer with Si nanoclusters at the Si-SiO
x
interface upon annealing. This process is caused by oxygen diffusion from the SiO
x
film, which occurs mainly via defects on the Si wafer surface. The photoconductivity spectrum of the samples charged by short-term
application of a negative potential to silicon exhibits electronic transitions in the SiO
x
film, both from the matrix electronic states and from the states of the defects and Si nanoclusters in the film. 相似文献
2.
S. Yu. Turishchev V. A. Terekhov D. A. Koyuda K. N. Pankov A. V. Ershov D. A. Grachev A. I. Mashin E. P. Domashevskaya 《Semiconductors》2013,47(10):1316-1323
Al2O3/SiO x /Al2O3/SiO x /…/Si(100) multilayer nanoperiodic structures (MNS) are studied by X-ray absorption near-edge structure spectroscopy (XANES). Experimental XANES spectroscopy spectra are obtained using synchrotron radiation. The formation of Si nanoclusters in the surface layers of the structures during their high-temperature annealing is observed. The structures featured intense size-dependent photoluminescence in the wavelength region near 800 nm. At the same time, it is shown that the formation of aluminum silicates is possible. The inversion effect of the intensity of the XANES spectra during the interaction of synchrotron radiation with MNSs is revealed. 相似文献
3.
Roushdey Salh L. Fitting E. V. Kolesnikova A. A. Sitnikova M. V. Zamoryanskaya B. Schmidt H. -J. Fitting 《Semiconductors》2007,41(4):381-386
High resolution transmission electron microscopy, scanning transmission electron microscopy, and cathodoluminescence have
been used to investigate Si and Ge cluster formation in amorphous silicon-dioxide layers. Commonly, cathodoluminescence emission
spectra of pure SiO2 are identified with particular defect centers within the atomic network of silica including the nonbridging oxygen hole center
associated with the red luminescence at 650 nm (1.9 eV) and the oxygen deficient centers with the blue (460 nm; 2.7 eV) and
ultraviolet band (295 nm; 4.2 eV). In Ge+ ion-implanted SiO2, an additional violet emission band appears at 410 nm (3.1 eV). The strong increase of this violet luminescence after thermal
annealing is associated with formation of low-dimension Ge aggregates such as dimers, trimers, and higher formations, further
growing to Ge nanoclusters. On the other hand, pure silica layers were modified by heavy electron beam irradiation (5 keV;
2.7 A/cm2), leading to electronic as well as thermal dissociation of oxygen and the appearance of under-stoichiometric SiOx. This SiOx will undergo a phase separation and we observe Si cluster formation with a most probable cluster diameter of 4 nm. Such largely
extended Si clusters will diminish the SiO2-related luminescence and Si-crystal-related luminescence in the near IR.
The text was submitted by the authors in English. 相似文献
4.
The results of the first studies of the effect of selective etching on photoluminescence in porous nc- Si–SiOx structures containing Si nanoclusters (nc-Si) in the SiOx matrix are reported. In the initial samples at room temperature, intense photoluminescence bands are observed with peaks
at 840 and 660 nm corresponding to radiative recombination of free charge carriers (or charge carriers bound to excitons)
excited in nc- Si. After selective etching of the nc- Si–SiOx structures in 1% HF solution, these bands are noticeably shifted to higher energies of the spectrum. It is suggested that
the evolution of the spectra is due to the decrease in the Si nanoparticle dimensions on etching of the oxide and additional
oxidation of nc- Si. The results show that selective etching of the oxide matrix can be used to control the radiation spectra of porous nc- Si–SiOx structures. 相似文献
5.
R. Kube H. Bracht J. Lundsgaard Hansen A. Nylandsted Larsen E.E. Haller S. Paul W. Lerch 《Materials Science in Semiconductor Processing》2008,11(5-6):378
Experiments on the diffusion of Si and Ge in Si1-xGex-isotope heterostructures with Ge contents x=0, 0.05, and 0.25 were performed at temperatures between 870 and . The concentration profiles of the stable Si- and Ge-isotopes were recorded by means of time-of-flight secondary ion mass spectrometry. For all compositions, an Arrhenius type temperature dependence of diffusion was observed. The activation enthalpy of Si diffusion in SiGe equals the activation enthalpy of Ge diffusion and the pre-exponential factors agree within experimental accuracy. However, the absolute values of the Si and Ge diffusion coefficients indicate a clear trend. In elemental Si the diffusion coefficients of Si and Ge agree, but the difference between the diffusion coefficients of Ge and Si in Si1-xGex increases with x. This indicates that with increasing Ge content the diffusional jumps of Ge atoms become more successful compared to that of Si. This trend is explained with an increasing contribution of vacancies to self-diffusion in Si1-xGex with an increase of the Ge content x. 相似文献
6.
An experimental investigation is conducted into the formation Ge nanoclusters by heat treatment of germanosilicate-glass (Si x Ge y O z ) films that are produced by oxidation of Ge-doped nanostructured polysilicon. It employs Auger and IR spectroscopy, high-resolution electron microscopy, and x-ray diffraction. The process by which Ge atoms in the films are transported toward the substrate is found to include the following stages: (1) the formation of a GeO2 and a SiO2 phase, (2) the reduction of GeO2 to Ge by Si, (3) Ge-crystallite nucleation, and (4) Ge-crystallite growth. Heat treatment in humid oxygen at ≥ 800°C is found to increase Ge-nanocluster size, the point of crystallization being 500°C. It is established that heat treatment at a temperature close to the Ge melting point results in complete aggregation of the germanium into clusters, with a twofold increase in both the mean size and the number of clusters. Germanium is found to accumulate at the interface between oxidized and unoxidized polysilicon. 相似文献
7.
D. M. Zhigunov N. V. Shvydun A. V. Emelyanov V. Yu. Timoshenko P. K. Kashkarov V. N. Seminogov 《Semiconductors》2012,46(3):354-359
The effect of the stoichiometry of thin silicon suboxide films on the processes of the formation and evolution of silicon
nanoclusters during thermal annealing is studied by photoluminescence measurements. The samples are produced by the thermal
sputtering of a SiO powder in an oxygen atmosphere, with the subsequent deposition of a 500 nm-thick SiO
x
layer onto a Si substrate. The morphological properties and size of Si nanoclusters are explored by analyzing the photoluminescence
spectra and kinetics. A comparative study of the luminescence properties of thin SiO
x
layers with different stoichiometric parameters, x = 1.10, 1.29, 1.56, and 1.68, is accomplished for samples annealed at different temperatures in the range 850 to 1200°C.
The dependences of the photoluminescence decay time on the annealing temperature, the stoichiometric parameter of the initial
silicon suboxide film, and the nanocluster size are studied. 相似文献
8.
M. V. Shaleev A. V. Novikov A. N. Yablonskiĭ O. A. Kuznetsov Yu. N. Drozdov Z. F. Krasil’nik 《Semiconductors》2007,41(2):167-171
The results of studying the photoluminescence of the structures with Ge(Si) self-assembled islands embedded into tensile-strained Si layer are reported. The structures were grown on smooth relaxed Si1 ? x Gex/Si(001) (x = 0.2–0.3) buffer layers. The photoluminescence peak found in the photoluminescence spectra of the studied structures is related to the indirect (in real space) optical transition between the holes localized in the Ge(Si) islands and electrons localized in the tensile-strained Si layers under and above an island. It is shown that one can efficiently control the position of the photoluminescence peak for a specified type of structure by varying the thickness of the strained Si layers. It is found that, at 77 K, the intensity of the photoluminescence signal from the heterostructures with Ge(Si) self-assembled islands contained between the tensile-strained Si layers exceeds by an order of magnitude the intensity of the photoluminescence signal from the GeSi structures with islands formed on the Si(001) substrates. 相似文献
9.
M. Lingalugari K. Baskar P.-Y. Chan P. Dufilie E. Suarez J. Chandy E. Heller F. C. Jain 《Journal of Electronic Materials》2013,42(11):3156-3163
Multistate behavior has been achieved in quantum dot gate field-effect transistor (QDGFET) configurations using either SiO x -cladded Si or GeO x -cladded Ge quantum dots (QDs) with asymmetric dot sizes. An alternative method is to use both SiO x -cladded Si and GeO x -cladded Ge QDs in QDGFETs. In this paper, we present experimental verification of four-state behavior observed in a QDGFET with cladded Si and Ge dots site-specifically self-assembled in the gate region over a thin SiO2 tunnel layer on a Si substrate. This paper also investigates the use of lattice-matched high-κ ZnS-ZnMgS-ZnS layers as a gate insulator in mixed-dot Si QDGFETs. Quantum-mechanical simulation of the transfer characteristic (I D–V G) shows four-state behavior with two intermediate states between the conventional ON and OFF states. 相似文献
10.
The epitaxial growth of an epi-Ge layer via GexSi1-xO2 reduction in hydrogen annealing is reported. GexSi+1-x alloys with x = 0.52 and 0.82 were first grown epitaxially on Si substrates. They were then oxidized in a wet ambient and
subsequently annealed in 5% or 100% H2. The reduction of Ge from its oxide state is observed in both samples with both ambients. However, an epitaxial Ge growth
is only observed in the sample with x = 0.82 after the 5% H2 annealing. The other three cases result in the formation of polycrystalline Ge. The roles of the hydrogen partial pressure
and the Ge content are discussed and conditions under which this novel mode of solid-phase epitaxy can occur are explained. 相似文献
11.
N. V. Vostokov Yu. N. Drozdov Z. F. Krasil’nik O. A. Kuznetsov D. N. Lobanov A. V. Novikov M. V. Shaleev 《Semiconductors》2006,40(2):229-233
The results of studying the growth of self-assembled Ge(Si) islands on relaxed Si1?xGex/Si(001) buffer layers (x≈25%), with a low surface roughness are reported. It is shown that the growth of self-assembled islands on the buffer SiGe layers is qualitatively similar to the growth of islands on the Si (001) surface. It is found that a variation in the surface morphology (the transition from dome-to hut-shaped islands) in the case of island growth on the relaxed SiGe buffer layers occurs at a higher temperature than for the Ge(Si)/Si(001) islands. This effect can be caused by both a lesser mismatch between the crystal lattices of an island and the buffer layer and a somewhat higher surface density of islands, when they are grown on an SiGe buffer layer. 相似文献
12.
SiN
x
:H films of different compositions grown on glass and silicon substrates using plasma-chemical vapor deposition at a temperature
of 380°C have been subjected to pulsed laser annealings. The treatments are performed using titanium-sapphire laser radiation
with a wavelength of 800 nm and a pulse duration of 30 fs. Structural changes in the films are studied using Raman spectroscopy.
Amorphous silicon nanoclusters are detected in as-grown films with molar fractions of excess silicon of ∼1/5 and larger. Conditions
required for pulsed crystallization of nanoclusters were determined. According to the Raman data, no silicon clusters were
detected in as-grown films with a small amount of excess silicon (x > 1.25). Pulsed treatments resulted in the formation of silicon nanoclusters 1–2 nm in size in these films. 相似文献
13.
N. V. Vostokov S. A. Gusev I. V. Dolgov Yu. N. Drozdov Z. F. Krasil’nik D. N. Lobanov L. D. Moldavskaya A. V. Novikov V. V. Postnikov D. O. Filatov 《Semiconductors》2000,34(1):6-10
The growth of self-assembled Ge islands on Si(001) surface and changes in the island structure parameters in the course of subsequent annealing were studied. Island structures possessing a small (~6%) scatter with respect to lateral dimensions and heights of the islands were obtained. The Raman spectra and X-ray diffraction data show evidence that silicon dissolves in the islands. The atomic fraction of Si in the resulting SixGe1?x solid solution was determined and the elastic strain in the islands was measured. It was found that annealing of the heterostructures with islands is accompanied by increasing Si fraction in the islands, which leads to changes in the island shape and size. 相似文献
14.
Kyu-Hwan Shim Hyeon Deok Yang Yeon-Ho Kil Jong-Han Yang Woong-Ki Hong Jeong-Jin Kim Sukill Kang Tae Soo Jeong Taek Sung Kim 《Materials Science in Semiconductor Processing》2013,16(1):126-130
We have investigated the Si0.8Ge0.2/Si multi-layer grown directly onto the Si (001) substrates using reduced pressure chemical vapor deposition. The thicknesses of the Si0.8Ge0.2/Si multi-layer were determined using transmission electron microscopy. From the results of energy-dispersive X-ray spectroscopy and X-ray diffraction analyses on the Si0.8Ge0.2/Si multi-layer, Ge composition in the Si1?xGex layers was determined as ~20% and the value of residual strain ε of the Si0.8Ge0.2 layer is calculated to be 0.012. Three peaks are observed in Raman spectrum, which are located at approximately 514, 404, and 303 cm?1, corresponding to the vibration of Si–Si, Si–Ge, and Ge–Ge phonons, respectively. The photoluminescence spectrum originates from the radiative recombinations both from the Si substrate and the Si0.8Ge0.2/Si multi-layer. For the Si0.8Ge0.2/Si multi-layer, the transition peaks related to the quantum well region observed in the photocurrent spectrum were preliminarily assigned to e–hh and e–lh fundamental excitonic transitions. 相似文献
15.
Yu. N. Drozdov Z. F. Krasil’nik D. N. Lobanov A. V. Novikov M. V. Shaleev A. N. Yablonskiĭ 《Semiconductors》2006,40(3):338-341
The effect of the predeposition of strained Si1 ? x Gex layers (x ≤ 20%) on photoluminescence (PL) of self-assembled Ge(Si)/Si(001) islands is studied. A shift of the PL peak related to dome-shaped islands (domes) to lower energies, with respect to the PL peak related to pyramidal islands is observed; this shift is related to a much larger height of the domes compared to that of pyramids. It is found that, as the Ge content in the Si1 ? x Gex layer (x) becomes higher than 0.1, two separate peaks appear in the broad PL band related to the islands; these peaks are attributed to the zero-phonon and phonon-assisted optical transitions in the islands. The appearance of these transitions is caused by a change of the TO-phonon type involved in radiative recombination: a TOGe-Ge phonon is replaced by a TOSi-Ge phonon with a shorter wavelength. 相似文献
16.
Sachin Joshi Sagnik Dey Michelle Chaumont Alan Campion Sanjay K. Banerjee 《Journal of Electronic Materials》2007,36(6):641-647
We demonstrate ultra-thin (<150 nm) Si1−x
Ge
x
dislocation blocking layers on Si substrates used for the fabrication of tensile-strained Si N channel metal oxide semiconductor
(NMOS) and Ge P channel metal oxide semiconductor (PMOS) devices. These layers were grown using ultra high vacuum chemical
vapor deposition (UHVCVD). The Ge mole fraction was varied in rapid, but distinct steps during the epitaxial layer growth.
This results in several Si1−x
Ge
x
interfaces in the epitaxially grown material with significant strain fields at these interfaces. The strain fields enable
a dislocation blocking mechanism at the Si1−x
Ge
x
interfaces on which we were able to deposit very smooth, atomically flat, tensile-strained Si and relaxed Ge layers for the
fabrication of high mobility N and P channel metal oxide semiconductor (MOS) devices, respectively. Both N and P channel metal
oxide semiconductor field effect transister (MOSFETs) were successfully fabricated using high-k dielectric and metal gates
on these layers, demonstrating that this technique of using ultra-thin dislocation blocking layers might be ideal for incorporating
high mobility channel materials in a conventional CMOS process. 相似文献
17.
R. Qian B. Anthony T. Hsu J. Irby D. Kinosky S. Banerjee A. Tasch 《Journal of Electronic Materials》1992,21(4):395-399
In this work, remote plasma-enhanced chemical vapor deposition (RPCVD) has been used to grow Ge
x
Si1−x
/Si layers on Si(100) substrates at 450° C. The RPCVD technique, unlike conventional plasma CVD, uses an Ar (or He) plasma
remote from the substrate to indirectly excite the reactant gases (SiH4 and GeH4) and drive the chemical deposition reactions. In situ reflection high energy electron diffraction, selected area diffraction,
and plan-view and cross-sectional transmission electron microscopy (XTEM) were used to confirm the single crystallinity of
these heterostructures, and secondary ion mass spectroscopy was used to verify abrupt transitions in the Ge profile. XTEM
shows very uniform layer thicknesses in the quantum well structures, suggesting a Frank/ van der Merwe 2-D growth mechanism.
The layers were found to be devoid of extended crystal defects such as misfit dislocations, dislocation loops, and stacking
faults, within the TEM detection limits (∼105 dislocations/cm2). Ge
x
Si1−x
/Si epitaxial films with various Ge mole fractions were grown, where the Ge contentx is linearly dependent on the GeH4 partial pressure in the gas phase for at leastx = 0 − 0.3. The incorporation rate of Ge from the gas phase was observed to be slightly higher than that of Si (1.3:1). 相似文献
18.
Structural characterization of thick, high-quality epitaxial Ge on Si substrates grown by low-energy plasma-enhanced chemical vapor deposition 总被引:1,自引:0,他引:1
Shawn G. Thomas Sushil Bharatan Robert E. Jones Rainer Thoma Thomas Zirkle N. V. Edwards Ran Liu Xiang Dong Wang Qianghua Xie Carsten Rosenblad Juergen Ramm Giovanni Isella Hans Von Känel 《Journal of Electronic Materials》2003,32(9):976-980
In this paper, we report on the growth of epitaxial Ge on a Si substrate by means of low-energy plasma-enhanced chemical vapor deposition (LEPECVD). A Si1?xGex graded buffer layer is used between the silicon substrate and the epitaxial Ge layer to reduce the threading dislocation density resulting from the lattice mismatch between Si and Ge. An advantage of the LEPECVD technique is the high growth rate achievable (on the order of 40 Å/sec), allowing thick SiGe graded buffer layers to be grown faster than by other epitaxial techniques and thereby increasing throughput in order to make such structures more manufacturable. We have achieved relaxed Ge on a silicon substrate with a threading dislocation density of 1 × 105 cm?2, which is 4?10x lower than previously reported results. 相似文献
19.
A. P. Detochenko S. A. Denisov M. N. Drozdov A. I. Mashin V. A. Gavva A. D. Bulanov A. V. Nezhdanov A. A. Ezhevskii M. V. Stepikhova V. Yu. Chalkov V. N. Trushin D. V. Shengurov V. G. Shengurov N. V. Abrosimov H. Riemann 《Semiconductors》2016,50(3):345-348
The technology of the growth of Si, Ge, and Si1–xGex layers by molecular-beam epitaxy with the use of a sublimation source of monoisotopic 30Si or 28Si and/or gas sources of monogermane 74GeH4 is demonstrated. All of the epitaxial layers are of high crystal quality. The secondary-ion mass spectroscopy data and Raman data suggest the high isotopic purity and structural perfection of the 30Si, 28Si, 74Ge, and 30Si1–x74Gex layers. The 30Si layers doped with Er exhibit an efficient photoluminescence signal. 相似文献
20.
V. A. Volodin A. I. Yakimov A. V. Dvurechenskiĭ M. D. Efremov A. I. Nikiforov E. I. Gatskevich G. D. Ivlev G. Yu. Mikhalev 《Semiconductors》2006,40(2):202-209
The goal of this study was the development of a method for the modification of a quantum dot (QD) structure in Ge/Si nanostructures by pulsed laser irradiation. The GexSi1?x QD structures were analyzed using data furnished by Raman spectroscopy. Frequency-dependent admittance measurements were used to study the energy spectrum of holes in the Ge/Si heterostructures with GexSi1?x QDs before and after the laser treatment. The obtained experimental data show that laser treatment makes it possible to reduce the sheet density of QDs, modify their composition, and increase the average size. The most important result is that the QD parameters become more uniform after the treatment with nanosecond laser pulses. In a sample with ODs of 8-nm average lateral size (six monolayers of Ge), the scatter of energy levels in the QD array is reduced by half after the treatment with 10 laser pulses. 相似文献