共查询到20条相似文献,搜索用时 15 毫秒
1.
V. G. Baru S. Bayliss V. A. Zhitov L. Yu. Zakharov G. Kartopu V. I. Pokalyakin A. Sapelkin G. V. Stepanov A. A. Timofeev O. F. Shevchenko 《Russian Microelectronics》2005,34(5):272-278
With a view to creating Si LEDs, the structural and luminescent properties of SiO x N y films containing Si nanocrystals in the SiO x N y matrix are studied experimentally. It is found that the film structure (nanocrystal size and concentration, the presence of an amorphous phase, etc.) and the spectrum and intensity of photoluminescence (PL) and electroluminescence (EL) are strongly dependent on the Si stoichiometric excess δ and annealing conditions. At δ≈ 10%, unannealed films are amorphous and contain Si clusters of size < 2 nm, as deduced from the TEM and microdiffraction data obtained. Annealing at 800–1000°C for 10–60 min produces Si crystals 3–5 nm in size with a concentration of ≈1018 cm?3. The annealed films exhibit room-temperature PL and EL over the wavelength range 400–850 nm with intensity peaks located at 50–60 and 60–70 nm, respectively. The PL and EL spectra are found to be qualitatively similar. This suggests that both the PL and the EL should be associated with the formation of luminescent centers at nanocrystal–matrix interfaces and in boundary regions. However, the two phenomena should differ in the mechanism by which the centers are excited. With the EL, excitation should occur by impact processes due to carrier heating in high electric fields. It is found that as δ increases, so does the proportion of large amorphous Si clusters with a high density of dangling bonds. This enhances nonradiative recombination and suppresses luminescence. 相似文献
2.
V. G. Baru V. I. Pokalyakin E. A. Skryleva 《Journal of Communications Technology and Electronics》2011,56(10):1227-1233
Features of formation, the composition, and the mictostructure of the luminescence-active transition region arising in the
course of the deposition of the SiO
x
N
y
(Si) nanocomposite layer with the use of the reactive ion sputtering of the Si target in the O2 and N2 atmosphere are studied. The composition and the microstructure of the transition regions are analyzed using the methods of
the X-ray photoelectron spectroscopy (XPS) upon the layer-by-layer etching of the composite layers. it is found that the transition
regions contain amorphous clusters and nanocrystals of Si as well as such nanoinclusions as Si-Si chains in the oxynitride
matrix. The influence of the microstructure on the characteristics of the electroluminescence of nanocomposite layers is revealed. 相似文献
3.
Jae-Hong Lim Mi Yeong Park Dong Chan Lim Bongyoung Yoo Jung-Ho Lee Nosang V. Myung Kyu Hwan Lee 《Journal of Electronic Materials》2011,40(5):1321-1325
Thermoelectric Sb
x
Te
y
films were potentiostatically electrodeposited in aqueous nitric acid electrolyte solutions containing different concentrations
of TeO2. Stoichiometric Sb
x
Te
y
films were obtained by applying a voltage of −0.15 V versus saturated calomel electrode (SCE) using a solution consisting
of 2.4 mM TeO2, 0.8 mM Sb2O3, 33 mM tartaric acid, and 1 M HNO3. The nearly stoichiometric Sb2Te3 films had a rhombohedral structure, R[`3]m R\bar{3}m , with a preferred orientation along the (015) direction. The films had hole concentration of 5.8 × 1018/cm3 and exhibited mobility of 54.8 cm2/Vs. A more negative potential resulted in higher Sb content in the deposited Sb
x
Te
y
films. Furthermore, it was observed that the hole concentration and mobility decreased with increasingly negative deposition
potential, and eventually showed insulating properties, possibly due to increased defect formation. The absolute value of
the Seebeck coefficient of the as-deposited Sb2Te3 thin film at room temperature was 118 μV/K. 相似文献
4.
A. V. Ershov D. I. Tetelbaum I. A. Chugrov A. I. Mashin A. N. Mikhaylov A. V. Nezhdanov A. A. Ershov I. A. Karabanova 《Semiconductors》2011,45(6):731-737
The photoluminescence, infrared absorption, and Raman spectra of amorphous multilayered nanoperiodic a-SiO
x
/ZrO2 structures produced by vacuum evaporation and then annealed at different temperatures (500–1100°C) are studied. It is established
that the evolution of the optical properties with increasing annealing temperature is controlled by sequential transformation
of Si clusters formed in the SiO
x
layers from nonphase inclusions to amorphous clusters and then to nanocrystals. The finally formed nanocrystals are limited
in sizes by the thickness of the initial SiO
x
layers and by chemical reactions with ZrO2. 相似文献
5.
I. Z. Indutnyy I. Yu. Maĭdanchuk V. I. Min’ko P. E. Shepelyavyĭ V. A. Dan’ko 《Semiconductors》2007,41(10):1248-1254
The effect of chemical treatment in saturated vapors of ammonia and acetone on the spectral composition and intensity of photoluminescence in porous SiO x films containing Si nanocrystals (nc-Si) is studied. The porosity of the SiO x films is provided by oblique vacuum deposition of thermally evaporated silicon or silicon monoxide on polished silicon substrates. The kinetics of adsorption of the vapors is monitored by variations in the frequency of a quartz oscillator on which the films to be studied are deposited. As a result of chemical treatment followed by high-temperature annealing of the SiO x films at the temperature 950°C, a new band, absent from the as-prepared films, appears in the photoluminescence spectrum at shorter wavelengths. The peak position and intensity of the band depend, correspondingly, on the composition of the film and on the time duration of the treatment. It is found that the new photoluminescence band is quenched upon exposure to laser radiation at the wavelength 488 nm. The quenching is more pronounced at the band peak. The possibility of controlling the characteristics of photoluminescence of the porous structures by chemical treatment is shown. 相似文献
6.
N. A. Vlasenko N. V. Sopinskii E. G. Gule V. V. Strelchuk P. F. Oleksenko L. I. Veligura A. S. Nikolenko M. A. Mukhlyo 《Semiconductors》2012,46(3):323-329
The photoluminescence of SiO
x
films deposited on c-Si wafers by the thermal evaporation of SiO in a vacuum and, for the first time, doped with ErF3 by coevaporation is studied. It is shown that, like undoped SiO
x
films, the unannealed SiO
x
:ErF3 films passivate the surface of the Si wafers and, thus, increase their edge photoluminescence intensity almost fivefold.
A similar increase is observed after annealing of the doped films in air at 750°C. Doping with ErF3 suppresses the photoluminescence of Si nanoclusters, if the films have been subjected to high-temperature annealing (at 750°C).
In this case, the PL intensity of the band with a peak at ∼890 nm decreases as well. The ∼890 nm band is observed for the
first time and, due to its features, is attributed to transitions in SiO
x
matrix defects. The experimentally observed effect of ErF3 doping on SiO
x
film photoluminescence is interpreted. An intense photoluminescence signal from Er3+ ions in the nearinfrared spectral region (the 4
I
11/2 → 4
I
15/2 and 4
I
13/2 → 4
I
15/2 transitions) is observed in the SiO
x
:ErF3 films annealed in air at 750°C. This finding shows that 1.54 μm luminescent emitters, which are currently in popular demand,
can be produced by a simple low-cost method. 相似文献
7.
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
8.
A. A. Lotin O. A. Novodvorsky E. V. Khaydukov V. N. Glebov V. V. Rocheva O. D. Khramova V. Ya. Panchenko C. Wenzel N. Trumpaicka K. D. Chtcherbachev 《Semiconductors》2010,44(2):246-250
The Mg
x
Zn1-x
O thin films with a Mg content corresponding to x = 0–0.45 are grown by pulsed laser deposition on ablation of ceramic targets. The conditions for epitaxial growth of the
films on the single-crystal Al2O3 (00.1) substrates are established. The record limit of solubility of Mg in hexagonal ZnO, x = 35 is attained. In this case, the lattice mismatch for the parameter a of the ZnO and Mg0.35Zn0.65O films does not exceed 1%, whereas the band gaps of the films differ by 0.78 eV. The surface roughness of the films corresponds
to 0.8–1.5 nm in the range of x = 0–0.27. 相似文献
9.
V. V. Bolotov V. E. Roslikov E. A. Kurdyukova O. V. Krivozubov Yu. A. Sten’kin D. V. Cheredov 《Semiconductors》2012,46(1):105-108
The electrical characteristics and chemical reactant sensitivity of layers of heterogeneous nanocomposites based on porous
silicon and nonstoichiometric tin oxide por-Si/SnO
x
, fabricated by the magnetron sputtering of tin with subsequent oxidation, are studied. It is shown that, in the nanocomposite
layers, a system of distributed heterojunctions (Si/SnO
x
nanocrystals) forms, which determine the electrical characteristics of such structures. The sensitivity of test sensor structures
based on por-Si/SnO
x
nanocomposites to NO2 is determined. A mechanism for the effect of the adsorption of NO2 molecules on the current-voltage characteristics of the por-Si(p)/SnO
x
(n) heterojunctions is suggested. 相似文献
10.
Y. Chen T. J. Zhu S. H. Yang S. N. Zhang W. Miao X. B. Zhao 《Journal of Electronic Materials》2010,39(9):1719-1723
A new preparation process combining melt spinning and hot pressing has been developed for the (Ag
x
SbTe
x/2+1.5)15(GeTe)85 (TAGS-85) system. Compared with samples prepared by the traditional air-quenching and hot-pressing method, electrical conductivity
and thermal conductivity are lowered. The thermoelectric performance of the TAGS-85 samples varied with changing Ag content
and reached the highest ZT of 1.48 when x was 0.8 for the melt-spun sample, compared with the maximum ZT of 1.36 for the air-quenched sample. The Seebeck coefficient of the melt-spun TAGS-85 alloys was improved, while both the
electrical conductivity and thermal conductivity were decreased. The net result of this process is to effectively enlarge
the temperature span of ZT > 1, which will benefit industrial application. 相似文献
11.
Evandro Daniel Calderaro Cotrim Luís Henrique de Carvalho Ferreira 《Analog Integrated Circuits and Signal Processing》2012,71(2):275-282
In this paper an ultra-low-power CMOS symmetrical operational transconductance amplifier (OTA) for low-frequency G
m
-C applications in weak inversion is presented. Its common mode input range and its linear input range can be made large using
DC shifting and bulk-driven differential pair configuration (without using complex approaches). The symmetrical OTA was successfully
verified in a standard CMOS 0.35-μm process. The measurements show an open loop gain of 61 dB and a unit gain frequency of
195 Hz with only 800 mV of power supply voltage and just 40 nW of power consumption. The transconductance is 66 nS, which
is suitable for low-frequency G
m
-C applications. 相似文献
12.
A. O. Evwaraye 《Journal of Electronic Materials》2010,39(6):751-755
n-Type 4H-SiC bulk samples with a net doping concentration of 2.5 × 1017 cm−3 were irradiated at room temperature with 1-MeV electrons. The high doping concentration plus a reverse bias of up to −13 V
ensures high electric field in the depletion region. The dependence of the emission rate on the electric field in the depletion
region was measured using deep-level transient spectroscopy (DLTS) and double-correlation deep-level transient spectroscopy
(DDLTS). The experimental data are adequately described by the phonon-assisted tunneling model proposed by Karpus and Pere. 相似文献
13.
V. A. Terekhov E. I. Terukov Yu. K. Undalov E. V. Parinova D. E. Spirin P. V. Seredin D. A. Minakov E. P. Domashevskaya 《Semiconductors》2016,50(2):212-216
The phase composition and optical properties of hydrogenated amorphous films of silicon suboxide (a-SiOx:H) with silicon nanoclusters are studied. Ultrasoft X-ray emission spectroscopy show that silicon- suboxide films with various oxidation states and various amorphous silicon-cluster contents can be grown using dc discharge modulation. In films with an ncl-Si content of ~50%, the optical-absorption edge is observed, whose extrapolation yields an optical band gap estimate of ~3.2–3.3 eV. In the visible region, rather intense photoluminescence bands are observed, whose peak positions indicate the formation of silicon nanoclusters 2.5–4.7 nm in size in these films, depending on the film composition. 相似文献
14.
Yu. M. Isaenko 《Journal of Communications Technology and Electronics》2009,54(1):27-39
The excitation of main parasitic modes E 11, H 11, and H 21, which have cutoff sections in a sectoral transition between modes H 10 and H 01, is investigated. It is shown that, for magnetic modes, including modes H 11 and H 21, it is unnecessary to use the Airy equation and that this circumstance simplifies the design relationships. The energies of these modes are calculated as functions of the transition parameters. 相似文献
15.
V. V. Brus M. I. Ilashchuk Z. D. Kovalyuk P. D. Maryanchuk K. S. Ulyanytsky B. N. Gritsyuk 《Semiconductors》2011,45(8):1077-1081
Surface-barrier anisotype n-TiO2/p-CdTe heterojunctions are fabricated by depositing thin titanium-dioxide films on a freshly cleaved surface of single-crystalline
cadmium-telluride wafers by reactive magnetron sputtering. It is established that the electric current through the heterojunctions
under investigation is formed by generation-recombination processes in the space-charge region via a deep energy level and
tunneling through the potential barrier. The depth and nature of the impurity centers involved in the charge transport are
determined. 相似文献
16.
N. T. Bagraev L. E. Klyachkin A. M. Malyarenko A. I. Ryskin A. S. Shcheulin 《Semiconductors》2005,39(5):528-532
Boron diffusion and the vapor-phase deposition of silicon layers are used to prepare ultrashallow p+-n junctions and p+-Si-n-CdF2 heterostructures on an n-CdF2 crystal surface. Forward portions of the I–V characteristics of the p+-n junctions and p+-Si-n-CdF2 heterojunctions reveal the CdF2 band gap (7.8 eV), as well as allow the identification of the valence-band structure of cadmium fluoride crystals. Under conditions in which forward bias is applied to the p+-Si-n-CdF2 heterojunctions, electroluminescence spectra are measured for the first time in the visible spectral region. 相似文献
17.
The aim of this study, to explain effects of the SiO2 insulator layer thickness on the electrical properties of Au/n-GaAs Shottky barrier diodes (SBDs). Thin (60 Å) and thick (250 Å) SiO2 insulator layers were deposited on n-type GaAs substrates using the plasma enganced chemical vapour deposition technique. The current-voltage (I–V) and capacitance-voltage (C-V) characteristics have been carried out at room temperature. The main electrical parameters, such as ideality factor (n), zero-bias barrier height (? Bo ), series resistance (R s ), leakage current, and interface states (N ss ) for Au/SiO2/n-GaAs SBDs have been investigated. Surface morphologies of the SiO2 dielectric layer was analyzed using atomic force microscopy. The results show that SiO2 insulator layer thickness very affects the main electrical parameters. Au/n-GaAs SBDs with thick SiO2 insulator layer have low leakage current level, small ideality factor, and low interface states. Thus, Au/n-GaAs SBDs with thick SiO2 insulator layer shows better diode characteristics than other. 相似文献
18.
The possibility of controlling the effective lifetime of nonequilibrium carriers by varying the lattice mismatch between the interfaced materials of a heterostructure has been studied on the example of InGaAs/GaAs heterostructures. It was found that, at a given composition (thickness) of a lightly doped layer of the InGaAs alloy, the nonequilibrium carrier lifetime depends on its thickness (composition), which enables variation of the nonequilibrium carrier lifetime from several nanoseconds to a microsecond without any significant change in the concentration of mobile carriers. The results obtained were used to fabricate pulse p +-p 0-π-n 0-n + diodes with blocking voltages of up to 500 V, which can switch currents of ≥10 A and have recovery times no longer than 10 ns. 相似文献
19.
This study reports the good thermal stability of a sputtered Cu(MoN
x
) seed layer on a barrierless Si substrate. A Cu film with a small amount of MoN
x
was deposited by reactive co-sputtering of Cu and Mo in an Ar/N2 gas mixture. After annealing at 560°C for 1 h, no copper silicide formation was observed at the interface of Cu and Si. Leakage
current and resistivity evaluations reveal the good thermal reliability of Cu with a dilute amount of MoN
x
at temperatures up to 560°C, suggesting its potential application in advanced barrierless metallization. The thermal performance
of Cu(MoN
x
) as a seed layer was evaluated when pure Cu is deposited on top. X-ray diffraction, focused ion beam microscopy, and transmission
electron microscopy results confirm the presence of an ∼10-nm-thick reaction layer formed at the seed layer/Si interface after
annealing at 630°C for 1 h. Although the exact composition and structure of this reaction layer could not be unambiguously
identified due to trace amounts of Mo and N, this reaction layer protects Cu from a detrimental reaction with Si. The Cu(MoN
x
) seed layer is thus considered to act as a diffusion buffer with stability up to 630°C for the barrierless Si scheme. An
electrical resistivity of 2.5 μΩ cm was obtained for the Cu/Cu(MoN
x
) scheme after annealing at 630°C. 相似文献
20.
O. A. Ageev A. E. Belyaev N. S. Boltovets V. N. Ivanov R. V. Konakova Ya. Ya. Kudryk P. M. Lytvyn V. V. Milenin A. V. Sachenko 《Semiconductors》2009,43(7):865-871
Mechanism of charge transport in a diode of a silicon carbide’s Schottky barrier formed by a quasi-amorphous interstitial phase TiB x on the surface of n-6H-SiC (0001) single crystals with an uncompensated donor (nitrogen) concentration of ~1018 cm?3 and dislocation density of ~(106–108) cm?2 has been studied. It is demonstrated that, at temperatures T ? 400 K, the charge transport is governed by the tunneling current along dislocations intersecting the space charge region. At T > 400 K, the mechanism of charge transport changes to a thermionic mechanism with a barrier height of ~0.64 eV and ideality factor close to 1.3. 相似文献