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The performance variation caused by the stress field near a through-silicon via (TSV) is measured using 28-nm node devices across 12-in wafers. The TSV is fabricated by a via-last process. The back-end-of-line dielectrics on TSV cause the asymmetric stress field, i.e., the absolute value of radial stress ( $\vert \sigma _{r}\vert )$ does not equal to that of tangential stress ( $\vert \sigma _{\theta }\vert )$ on silicon and leads to the asymmetric keep-out zone (KOZ), different from previously reported. A modified KOZ model with the asymmetric radial and tangential stress field is proposed and verified by 3-D finite-element analysis simulation and experiment data. The physics behind the asymmetry is also described. Comparable KOZ size for nFETs and pFETs is observed.

Impact of via-last through-silicon via (TSV) on 28nm node devices is investigated. The stress field of TSV is affected by the back-end-of-line (BEOL) dielectrics. The absolute value of radial stress (|σr|) is different from that of tangential stress (|σθ|) on silicon, which leads to the asymmetric keep-out zone (KOZ). The physics behind the asymmetry is also described. A modified KOZ model considering the asymmetric stress field is proposed and verified by experiment data.

Primary, high density bovine articular chondrocyte (BAC) cultures, stimulated with transforming growth factor-beta-1, elaborated a high molecular weight anionic glycoconjugate, kDa 540, which does not contain glycosaminoglycan chains (Chan and Anastassiades, 1996). The effect of exogenously added transforming growth factor-beta-1 on the elaboration of the high molecular weight glycoconjugate and of proteoglycans was studied during dedifferentiation of the chondrocytes, utilizing a serial subculture technique under anchorage-dependent conditions, up to four subcultures. The high molecular weight glycoconjugate was detected in the media of all growth-factor-stimulated chondrocyte subcultures, as well as stimulated primary cultures, but not in unstimulated primary cultures or subcultures. By contrast, a large proteoglycan, was only secreted by primary cultures and first subcultures, whether treated with transforming growth factor-beta-1 or untreated. This proteoglycan contained mostly chondroitin sulfate chains, whose hydrodynamic size was increased by the addition of transforming growth factor-beta-1. Further, the pattern of the proteoglycans appearing in the media of subcultures 2-4 was influenced by the addition of transforming growth factor-beta-1, so that while these control subcultures elaborated both the large and small chondroitin sulfate proteoglycans, the equivalent stimulated subcultures elaborated only intermediate sized chondroitin sulfate proteoglycan(s). These results suggest that while dedifferentiation of articular chondrocytes, achieved by subculturing, strongly modulates the effect of exogenously added transforming growth factor-beta-1 on the type of proteoglycan elaborated, the process of dedifferentiation does not influence the transforming-growth-factor-beta-dependent synthesis of the high molecular weight anionic glycoconjugate.

The influence of polystyrene beads (80 μm) and nylon fibres on the water permeability of bleached kraft wood pulp fibre pads was measured and the results were regressed to the Kozeny-Carman equation. SEM micrographs of pad cross sections showed that the beads, which were uniformly distributed, had little effect on pad structure whereas the long rigid nylon fibres made the pads more difficult to compress. The pad specific surface areas and swollen volumes were linear functions of the content of beads or nylon fibres. This suggests that the fibre pad permeability characteristics could be adequately modeled from the linear superposition of geometric properties of the pad constituents. L'influence des billes de polystyrene (80 μm) et des fibres de nylon sur la permeabilite a l'eau de tampons de fibre de pǎte a papier Kraft blanchie a ete mesuree, et les resultats sont traites avec l'equation de Kozeny-Carman. Des micrographies SEM (microscopie electronique a balayage) de sections transversales des tampons montrent que les billes, qui sont uniformement distribuees, ont peu d'effet sur la structure des tampons, alors que les fibres de nylon rigides longues rendent les tampons plus difficiles a comprimer. La surface specifique des tampons et les volumes gonfles sont des fonctions lineaires de la teneur en billes ou en fibres de nylon. Ceci suggere que les caracteristiques de permeabilite des tampons de fibres pourrait ětre adequatement modelisees par la superposition lineaire des proprietes geometriques des constituants des tampons.

The isochronal and isothermal annealing characteristics of acceptor‐doped GaAs:Be grown at low substrate temperatures (300 °C) by molecular‐beam epitaxy (LTMBE) have been studied. The Be was introduced in a range of concentrations from 1016 to 1019 cm−3. Electrical measurements of as‐grown material up to the highest Be concentration of 1019 cm−3 show that no free holes are contributed to the valence band even though Raman spectroscopy of the Be local vibrational mode indicates that the majority of the Be impurities occupy substitutional sites. It is proposed that Be acceptors are rendered inactive by the high concentration of AsGa‐related native donor defects present in LTMBE material. The concentration of AsGa‐related defects in the neutral charge state was estimated from infrared absorption measurements to be as high as 3×1019 cm−3. A distinct annealing stage at 500 °C, similar to that found in irradiation‐damaged and plastically deformed GaAs, marks a rapid decrease in the concentration of AsGa‐related...

In the dormitories of universities, the indoor air quality (IAQ) is especial concern, which greatly affects the learning efficiency and students' physical and mental health. In order to improve the IAQ of student dormitories, the present characteristics of IAQ should be investigated. In this paper, the measurement of the IAQ was conducted in student dormitories on a campus in Chongqing. The investigation includes two parts: site measurement and subjective questionnaire investigations. The measured indexes include air temperature, relative humidity, the concentration distribution of carbon dioxide (CO 2 ), carbon monoxide (CO), sulfur dioxide (SO 2 ), nitrogen dioxide (Nox), respirable suspended particulates (PM10), total number of bacteria (TNB), etc. The measured data showed that the concentration of CO 2 , SO 2 , PM10 and total number of bacteria were beyond the amount stipulated in related standards, and the thermal environment needed improved. For the sake of reflecting the IAQ comprehensively, the subjective investigation was also conducted with questionnaires. The site measurement and questionnaire investigation showed that it was necessary to improve the IAQ of student dormitories, which could be done by increasing the ventilation rate by means of a mechanical system.

A wavelength-tunable actively mode-locked erbium fiber ring laser was demonstrated using a Fabry–Perot semiconductor modulator. The modulator played the simultaneous roles of an intensity mode locker and a tunable optical filter. Stable single- or dual-wavelength nearly transform-limited picosecond pulses at gigabit repetition rates were generated. Continuous wavelength tuning was achieved by simply controlling the temperature of the modulator. Pulse train with a repetition rate up to 19.93 GHz (eight times the driving frequency) was obtained by using rational harmonic mode-locking technique.

For organometallic vapor phase epitaxial (OMVPE) grown InP, the change in lattice constant is measured as a function of tellurium (Te) dopant concentration. We observe ~0.15% dilation in the InP lattice constant at a Te concentration of ~1020 cm-3. Our measurements are compared to predictions from Vegard’s Law.

We have successfully grown bulk In0.53Ga0.47As on InP using tertiarybutylarsine (TBA), trimethylindium and trimethylgallium. The growth temperature was 602° and the V/III ratio ranged from 19 to 38. Net carrier concentrations were 2 – 4 × 1015 cm-3, n-type, with a peak 77 K mobility of 68,000 cm2/V. sec. Increasing compensation was observed in In0.53Ga0.47As grown at higher V/III ratios. PL spectra taken at 5 K revealed strong near bandgap emission at 0.81 eV—with the best sample having a FWHM of 2.5 meV. At lower energies, donor-acceptor pair transitions were evident. Strong and sharp 5 K PL emission was observed from InP/In0.53Ga0.47As/InP quantum wells grown with TBA.

Electrical single- and dual-wavelength tuning and three-wavelength operation of an actively mode-locked fiber ring laser generating picosecond pulses were demonstrated by using a cavity with large dispersion. A continuous tuning range up to ∼37 nm of single-wavelength picosecond pulses at ∼1 GHz was achieved by only changing the modulation frequency. Continuous wavelength tuning of dual-wavelength (18.5 nm spacing) 3 GHz picosecond pulses was also demonstrated with a tuning range up to ∼17 nm. The tuning ranges were mainly limited by the gain bandwidth of the Er-doped fiber. Simultaneous generation of three-wavelength picosecond pulses at ∼2 GHz was also demonstrated by further increasing the cavity dispersion.

We have investigated strained InGaAs single quantum well structures using MeV ion beam methods. The structural properties of these structures, including composition and well size, have been studied. It has been found that the composition obtained by Rutherford backscattering spectrometry and particle‐induced x‐ray emission techniques agrees very well with that obtained by the ion channeling method.

A high molecular weight anionic glycoconjugate was isolated from the media of the transforming growth factor-β treated chondrocyte cultures by anion-exchange chromatography on DEAE–Sephacel and Mono Q columns and was partially characterized. This high molecular weight anionic glycoconjugate was not detected in the non-treated (control) cultures. Characterization studies showed that the glycoconjugate is a non-reducible, non-collagenous glycoprotein containing O-linked, N-linked, and sialic acid substituted carbohydrate units. The isolated glycoconjugate stained "blue" with Stains All and migrated as a single band on sodium dodecyl sulfate gradient gels (2.5–10% acrylamide – diallyl tartardiamide) at an estimated molecular weight of 540 000. Amino acid and amino sugar analyses showed that it is rich in aspartic acid – asparagine, glutamic acid – glutamine, alanine, proline, and glycine, and contains galactosamine and glucoasmine. This transforming growth factor-β inducible glycoprotein may be involved in cell differentiation and in the cartilage repair process. It may also be used as a marker to localize the biological activity of transforming growth factor-β in articular cartilage.Key words: transforming growth factor-β, chondrocytes, anionic glycoconjugate synthesis.

Anchorage-dependent cultures of a population of cells derived from the outer part of the rat calvaria demonstrated decreased net accumulation of radiolabeled chondroitin sulfate (CS) and hyaluronic acid (HA) per cell as the cell density of the cultures increased. The addition of TGF-beta 1 resulted in large stimulations of the net CS, but not of the net HA, accumulating in the medium at all cell densities and an abolition of the density-dependent effect. These effects were largely due to increases in newly synthesized CS appearing in the medium. Supplementation of the culture media with CS had complex but relatively small effects on the stimulation of the net accumulation of radiolabeled medium CS by TGF-beta 1. The addition of TGF-beta 1 also resulted in a biphasic effect on cell growth that depended on the plating density, but cell growth differences could not account for the marked stimulation of CS synthesis by TGF-beta 1. Experiments with cycloheximide and beta-xyloside and isolation of the intact anionic glycoconjugates (AG) indicated that although synthesis of core protein was the limiting factor in CS synthesis, TGF-beta 1 stimulated the synthesis of CS chain when sufficient beta-xyloside acceptor was available. The overall results suggest that, in this cell system, the action of TGF-beta 1 on the synthesis of the major extracellular AGs is characterized by a relatively specific upregulation of CS proteoglycan (PG) synthesis and an uncoupling of the inhibitory effect of high cell density on CS PG synthesis.

For the thick 50 A oxide, the Cu contamination slightly increases the gate oxide leakage current in the pretunneling region, which may be attributed to the trap-assisted tunneling. The reason why the Cu contamination has little effect on the F-N tunneling may be due to a much larger current conduction than the trap-assisted tunneling at large bias. In contrast, a large leakage current is also observed in the direct tunneling region in addition to the increased pretunneling current. The two orders of magnitude larger leakage current at direct tunneling regime is unacceptable for low power circuit application. If a thinner oxide has a similar increasing trend for the leakage

The growth of unintentionally doped indium phosphide by low pressure metalorganic chemical vapor deposition (LPMOCVD) using triethlylindium and phosphine has been investigated by low temperature photoluminescence (PL). Pregrowth annealing was found to result in improved crystalline quality of the seed surface. The predominant acceptor impurity on the annealed substrate surface and in the initial epitaxial region (1200 A) was shown to be carbon. The major acceptor impurity in thicker epilayers further away from the substrate interface was determined to be Zn. Silicon was also identified from the PL spectra, though its concentration might be much smaller than that of zinc. No deep level impurities were observed in this material. Most important of all, the highly resolved exciton PL spectrum demonstrated that excellent quality InP comparable to the best material grown by vapor phase epitaxy could be grown by LPMOCVD without the need for phosphine cracking.

High‐quality modulation doped In0.53Ga0.47As/InP heterostructures have been grown by atmospheric pressure metalorganic chemical‐vapor deposition (MOCVD) using solid trimethylindium source. The two‐dimensional nature of electrons bound in the In0.53Ga0.47As/InP heterojunctions is proved by a Shubnikov‐de Haas effect experiment. Electron Hall mobilities as high as 12000, 83000, 98000, and 92000 cm2/V s at 300, 77, 40, and 4.2 K are obtained, respectively. The electron effective mass is measured to be m*CR =0.043 m0 by cyclotron resonance experiments on the samples with two‐dimensional electron sheet concentrations of (3.0–3.7)×1011/cm2. From far‐infrared impurity absorption data the ionization energy of the residual donors in the MOCVD‐grown In0.53Ga0.47As is determined to be 2.95 meV.

Hall effect and transverse magnetoresistance have been detected in unilluminated monocrystalline trigonal selenium samples at room temperature with a signal-to-noise ratio of the order of ten. The magnetoresistance change increased quadratically with magnetic field strength (B). An average hole mobility (μ1μ3)1/2 of 80 cm2 V−1s−1 was obtained from magnetoresistance of 37 cm2 V−1 s−1 from magnetoconductivity assuming the existence of inhomogeneity effects. Hall mobilities were two orders of magnitude smaller. Hall voltage was found to increase linearly with B but slightly superlinearly with sample current. Halleffekt und transversaler transversaler Magnetowiderstand wurden an unbelichteten, monokristallinen, trigonalen Selenproben bei Zimmertemperatur und mit einem Rauschabstand der Grosenordnug von zehn nachgewiesen. Die Magnetowiderstandsanderung nahm mit der magnetischen Feldstarke (B) quadratisch zu. Es ergab sich ein Durchschnittswert der Locherbeweglichkeit (μ1μ3)1/2 von 80 cm2 V−1 s−1 aus dem Magnetowiderstand bzw. 37 cm2 V−1 s−1 aus der Magnetoleitfahigkeit, wobei das Vorhandensein von Inhomogenitaten angenommen wird. Die Hallbeweglichkeiten waren grosenordnungsmasig zweimal kleiner. Die Hallspannung nahm mit B linear bzw. mit dem Probenstrom geringfugig uberlinear zu.

We have found a new electron trap state in Si‐doped AlxGa1−xAs by deep level transient spectroscopy and constant temperature capacitance transient measurements under strong light illumination. This new trap is shallower than the DX center associated with Si impurity in that its emission and capture activation energies are equal to 0.20±0.05 and 0.17±0.05 eV, respectively. Its maximum concentration is comparable to the concentration of the DX center. Possible origins of this new trap and its relationship to the DX center are discussed.

The uninterrupted growth of high quality GaInAs layers on InP buffers by atmospheric pressure metalorganic chemical vapor deposition using trimethylindium is reported. A lattice mismatch smaller than 4.3×10−4 and low‐temperature photoluminescence exciton linewidth of 2.6 meV have been obtained, along with best 300‐K, 77‐K, and 4.2‐K Hall mobilities of 11 200, 64 000, and 80 000 cm2/Vs, respectively. Such high mobility values at 4.2 K are explained by the existence of a two‐dimensional electron gas and demonstrate the superior quality of the GaInAs epilayers grown in our laboratory.

Growth of very high quality unintentionally doped InP by low pressure metalorganic vapor phase epitaxy using solid trimethylindium as the indium source is described. Hall mobilities of 5370 cm2/Vs (300 K) and 131 600 cm2/Vs (77 K) with residual carrier concentration of 2.5×1014 cm−3 have been obtained. Low‐temperature photoluminescence exciton spectra revealed that the neutral acceptor‐bound‐exciton emission was hardly observable, indicating a very low compensation ratio.