Low Dimension Properties of Nanostructures on Ultrathin Layers of Silicon Formed by Oxidation of Ion Cut SOI Wafers and Electron Lithography

Conductor, resistor, and dielectric patterns of microelectronic device are usually defined by exposure of a photosensitive material through a mask onto the device with subsequent development of the photoresist and chemical removal of the undesired materials. Standard optical techniques are limited and electron lithography provides several important advantages, including the ability to expose features as small as 1,000 Å, and direct exposure on the wafer with no intermediate mask. This presentation is intended to report how electron lithography was used to define the permalloy patterns which are used to manipulate domains in magnetic bubble memory devices.The electron optical system used in our experiment as shown in Fig. 1 consisted of a high resolution scanning electron microscope, a computer, and a high precision motorized specimen stage. The computer is appropriately interfaced to address the electron beam, control beam exposure, and move the specimen stage.

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Electron correlation phenomena in semiconductor low-dimension structures and nanostructures

Uspekhi Fizicheskih Nauk ◽

10.3367/ufnr.0174.200410f.1109 ◽

2004 ◽

Vol 174 (10) ◽

pp. 1109

Author(s):

Vladislav B. Timofeev

Keyword(s):

Electron Correlation ◽

Low Dimension

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Low-Dimension Electronic Precesses in High Mobility GaAs/Al(x) Ga(1-x)As Nanostructures

10.21236/ada344651 ◽

1998 ◽

Author(s):

D. C. Tsui ◽

M. Shayegan

Keyword(s):

High Mobility ◽

Low Dimension

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ВЛИЯНИЕ ТВЕРДОФАЗНОЙ РЕКРИСТАЛЛИЗАЦИИ С ДВОЙНОЙ ИМПЛАНТАЦИЕЙ НА ПЛОТНОСТЬ СТРУКТУРНЫХ ДЕФЕКТОВ В УЛЬТРАТОНКИХ СЛОЯХ КРЕМНИЯ НА САПФИРЕ

Nanoindustry Russia ◽

10.22184/1993-8578.2020.13.3s.154.159 ◽

2020 ◽

Vol 96 (3s) ◽

pp. 154-159

Author(s):

Н.Н. Егоров ◽

С.А. Голубков ◽

С.Д. Федотов ◽

В.Н. Стаценко ◽

А.А. Романов ◽

...

Keyword(s):

Dislocation Density ◽

Solid Phase ◽

Modern Method ◽

Structural Defects ◽

Structural Quality ◽

Mos Transistors ◽

Ultrathin Layers ◽

Heteroepitaxial Layers ◽

Xrd And Tem

Высокая плотность структурных дефектов является основной проблемой при изготовлении электроники на гетероструктурах «кремний на сапфире» (КНС). Современный метод получения ультратонких структур КНС с помощью твердофазной эпитаксиальной рекристаллизации позволяет значительно снизить дефектность в гетероэпитаксиальном слое КНС. В данной работе ультратонкие (100 нм) слои КНС были получены путем рекристаллизации и утонения субмикронных (300 нм) слоев кремния на сапфире, обладающих различным структурным качеством. Плотность структурных дефектов в слоях КНС оценивалась с помощью рентгеноструктурного анализа и просвечивающей электронной микроскопии. Кривые качания от дифракционного отражения Si(400), полученные в ω-геометрии, продемонстрировали максимальную ширину на полувысоте пика не более 0,19-0,20° для ультратонких слоев КНС толщиной 100 нм. Формирование структурно совершенного субмикронного слоя КНС 300 нм на этапе газофазной эпитаксии обеспечивает существенное уменьшение плотности дислокаций в ультратонком кремнии на сапфире до значений ~1 • 104 см-1. Тестовые n-канальные МОП-транзисторы на ультратонких структурах КНС характеризовались подвижностью носителей в канале 725 см2 Вс-1. The high density of structural defects is the main problem on the way to the production of electronics on silicon-on-sapphire (SOS) heteroepitaxial wafers. The modern method of obtaining ultrathin SOS wafers is solid-phase epitaxial recrystallization which can significantly reduce the density of defects in the SOS heteroepitaxial layers. In the current work, ultrathin (100 nm) SOS layers were obtained by recrystallization and thinning of submicron (300 nm) SOS layers, which have various structural quality. The density of structural defects in the layers was estimated by using XRD and TEM. Full width at half maximum of rocking curves (ω-geometry) was no more than 0.19-0.20° for 100 nm ultra-thin SOS layers. The structural quality of 300 nm submicron SOS layers, which were obtained by CVD, depends on dislocation density in 100 nm ultrathin layers. The dislocation density in ultrathin SOS layers was reduced by ~1 • 104 cm-1 due to the utilization of the submicron SOS with good crystal quality. Test n-channel MOS transistors based on ultra-thin SOS wafers were characterized by electron mobility in the channel 725 cm2 V-1 s-1.

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Poly(methyl-phenylsilylene) Derivatives as Photoconductors

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19932337 ◽

1993 ◽

Vol 58 (10) ◽

pp. 2337-2348 ◽

Cited By ~ 19

Author(s):

Ivan Kmínek ◽

Stanislav Nešpůrek ◽

Eduard Brynda ◽

Jiří Pfleger ◽

Věra Cimrová ◽

...

Keyword(s):

Spectral Properties ◽

Long Wavelength ◽

Langmuir Blodgett ◽

Ultrathin Layers ◽

Polar Derivatives ◽

Derivatives Of

The attachment of long wavelength absorbing π-conjugated chromophores to poly(methyl-phenylsilylene) (PMPSi) via reactions of its formylated derivative is described. Some of the obtained polymers exhibit improved photostability in comparison with the parent polymer. Their spectral properties and photoconductivity are discussed. Ultrathin layers and multilayers were prepared from polar derivatives of PMPSi by the Langmuir-Blodgett technique and their photoconductive behaviour was studied.

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Phenomenological Modelling

10.1093/oso/9780198782933.003.0009 ◽

2018 ◽

Author(s):

Ray Huffaker ◽

Marco Bittelli ◽

Rodolfo Rosa

Keyword(s):

Nonlinear Dynamics ◽

Time Series ◽

Real World ◽

Biological Diversity ◽

False Positives ◽

World Systems ◽

Economic Activities ◽

Essential Services ◽

Low Dimension ◽

Convergent Cross Mapping

Detecting causal interactions among climatic, environmental, and human forces in complex biophysical systems is essential for understanding how these systems function and how public policies can be devised that protect the flow of essential services to biological diversity, agriculture, and other core economic activities. Convergent Cross Mapping (CCM) detects causal networks in real-world systems diagnosed with deterministic, low-dimension, and nonlinear dynamics. If CCM detects correspondence between phase spaces reconstructed from observed time series variables, then the variables are determined to causally interact in the same dynamic system. CCM can give false positives by misconstruing synchronized variables as causally interactive. Extended (delayed) CCM screens for false positives among synchronized variables.

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Synthesis and size control of Si nanocrystals by SiO/SiO2 superlattices and Er doping

MRS Proceedings ◽

10.1557/proc-737-f1.6 ◽

2002 ◽

Vol 737 ◽

Cited By ~ 1

Author(s):

J. Heitmann ◽

D. Kovalev ◽

M. Schmidt ◽

L.X. Yi ◽

R. Scholz ◽

...

Keyword(s):

Phase Separation ◽

Crystal Size ◽

Radiative Lifetime ◽

Size Control ◽

Luminescence Signal ◽

Er Doping ◽

Size Dependent ◽

Transmission Electron ◽

Si Nanocrystals ◽

Ultrathin Layers

ABSTRACTThe synthesis of nc-Si by reactive evaporation of SiO and subsequent thermal induced phase separation is reported. The size control of nc-Si is realized by evaporation of SiO/SiO2 superlattices. By this method an independent control of crystal size and density is possible. The phase separation of SiO into SiO2 and nc-Si in the limit of ultrathin layers is investigated. Different steps of this phase separation are characterized by photoluminescence, infrared absorption and transmission electron microscopy measurements. The strong room temperature luminescence of nc-Si shows a strong blueshift of the photoluminescence signal from 850 to 750 nm with decreasing crystal size. Several size dependent properties of this luminescence signal, like decreasing radiative lifetime and increasing no-phonon transition properties with decreasing crystal size are in good agreement with the quantum confinement model. Er doping of the nc-Si shows an enhancement of the Er luminescence at 1.54 μm by a factor of 5000 compared to doped SiO2 layers. The decreasing transfer time for the nc-Si to Er transition with decreasing crystal size can be understood as additional proof of increasing recombination probability within the nc-Si for decreasing crystal size.

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Symmetries and anomalies of (1+1)d theories: 2-groups and symmetry fractionalization

Journal of High Energy Physics ◽

10.1007/jhep08(2021)061 ◽

2021 ◽

Vol 2021 (8) ◽

Author(s):

Matthew Yu

Keyword(s):

Spectral Sequence ◽

Global Symmetries ◽

Group Symmetry ◽

Low Dimension ◽

The One ◽

Group Symmetries

Abstract We investigate the interactions of discrete zero-form and one-form global symmetries in (1+1)d theories. Focus is put on the interactions that the symmetries can have on each other, which in this low dimension result in 2-group symmetries or symmetry fractionalization. A large part of the discussion will be to understand a major feature in (1+1)d: the multiple sectors into which a theory decomposes. We perform gauging of the one-form symmetry, and remark on the effects this has on our theories, especially in the case when there is a global 2-group symmetry. We also implement the spectral sequence to calculate anomalies for the 2-group theories and symmetry fractionalized theory in the bosonic and fermionic cases. Lastly, we discuss topological manipulations on the operators which implement the symmetries, and draw insights on the (1+1)d effects of such manipulations by coupling to a bulk (2+1)d theory.

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