Plasma Deposition of a-Si:H

1984 ◽  
Vol 38 ◽  
Author(s):  
John C. Knights
Keyword(s):  
Gas Phase ◽  
Plasma Deposition ◽  
Substrate Surface ◽  
Silicon Film ◽  
Reaction Products ◽  
Primary Reaction ◽  
Second Stage ◽  
Third Stage ◽  
Secondary Reactions ◽  
Hydrogenated Amorphous

AbstractThere are four easily identified stages in the formation of a hydrogenated amorphous silicon film from an electrical discharge in silane. The first stage is the primary reaction between electrons and silane resulting in a mixture of ions and free radicals. The second stage is the transport of these species to the substrate surface accompanied in parallel by a multiplicity of secondary reactions e.g. ion-molecule, photon-molecule, etc. The third stage is the reaction or adsorption of these species with or onto the substrate surface and the fourth stage is the process by which these species or their reaction products incorporate into the growing film or are reemitted from the surface into the gas phase.

Thiirene formation in the reactions of sulfur atoms with alkynes

1983 ◽  
Vol 61 (10) ◽  
pp. 2268-2281 ◽  
Author(s):  
Bela Verkoczy ◽  
Alden G. Sherwood ◽  
Imre Safarik ◽  
Otto P. Strausz
Keyword(s):  
Gas Phase ◽  
New Products ◽  
Reaction Products ◽  
Gas Phase Reactions ◽  
Bimolecular Reactions ◽  
Primary Products ◽  
End Products ◽  
Secondary Reactions

The gas phase reactions of S(1D2) and S(3PJ) atoms with alkynes have been studied by photolyzing COS in the presence of CH≡CH, CF3C≡CH, and CF3C≡CCF3. In the reactions with CH≡CH, CS2, benzene, and thiophene were formed; with CF3C≡CH, eight products were found with disubstituted thiophenes and trisubstituted benzenes as the major products. In the case of CF3C≡CCF3, only perfluorotetramethylthiophene was detected at low conversion but at long photolysis several new products were observed. Many of the reaction products characterized here have not been reported before.The formation and distribution of the reaction products could be rationalized by an overall mechanism in which the formation of the highly reactive primary adducts, thiirene and thioformylmethylene, is followed by bimolecular reactions yielding the principal end products. The formation of minor products could be explained by secondary photoisomerizations, secondary photolysis, and by secondary decompositions and the secondary reactions of sulfur atoms with primary products.

A NOVEL METHOD TO EVALUATE PLASMA DEPOSITED SILICON OXIDE BARRIER FILMS BY WATER CONTACT ANGLE MEASUREMENT UNDER DC VOLTAGE APPLICATION (FOR CONFERENCE PUBLICATIONS FROM ACCS 2011)

2012 ◽  
Vol 24 (02) ◽  
pp. 165-169
Author(s):  
Ko-Shao Chen ◽  
Chin-Yen Chou ◽  
Shu-Chuan Liao ◽  
Chia-Hui Tsao ◽  
Hsin-Ming Wu
Keyword(s):  
Thin Film ◽  
Contact Angle ◽  
Water Contact Angle ◽  
Plasma Deposition ◽  
Substrate Surface ◽  
Silicon Film ◽  
Angle Measurement ◽  
Silicon Thin Film ◽  
Water Contact ◽  
Organic Silicon

In this study, organic silicon thin film was deposited on a comb type electrode substrate surface using hexamethyldisilazane (HMDSZ) plasma deposition technique to enhance voltage withstanding capability. The wettability, morphology and capability to withstand voltage were investigated by water contact angle (WCA) measurement, SEM observations, AFM and ampere meter analysis, respectively. The WCA of the substrate is 92.3° after the plasma deposition. As voltage is applied to the electrode, the WCA lowers to 76.4° and the resulting current flow is 0.078 mA. If the voltage is continually applied to the device, the organic silicon film on the substrate starts to peel off, accompanied with a sharp increase in current, which is an irreversible phenomenon. From the SEM and AFM analysis, the voltage withstanding capability of the device can be enhanced by prolonging the plasma processing time in order to obtain thicker thin film.

Surface Chemistry of CVD Reactions Studied by Molecular Beam/Surface Scattering

1990 ◽  
Vol 204 ◽  
Author(s):  
Ming L. Yu ◽  
Ulrich Memmert ◽  
Nicholas I. Buchan ◽  
Thomas F. Kuech
Keyword(s):  
Surface Chemistry ◽  
Real Time ◽  
Gas Phase ◽  
Molecular Beam ◽  
Substrate Surface ◽  
Atomic Layer ◽  
Molecular Beams ◽  
Surface Scattering ◽  
Reaction Products ◽  
Beam Surface

ABSTRACTA molecular beam/surface scattering experiment in an ultrahigh vacuum is conceptually a simulation of a CVD reactor without the interference from gas phase and wall reactions. The surface chemistry can be studied in real-time during the deposition reaction at the desired temperature. In our experiment, we used pulsed molecular beams of the reactants and a mass spectrometer to monitor In real-time the reaction products evolving from the substrate surface. With this arrangement, the reaction probability of the molecules can readily be determined by measuring the unreacted fraction of the molecular beam. The reaction pathways can be deduced from the Identification of the reaction products, while their time-evolutions give the kinetic parameters. We shall illustrate this technique by our study on the reactions of trimethylgallium and triethylgallium on GaAs as related to the metalorganic CVD and atomic layer epitaxy of GaAs.

COMPUTER MODELING OF CHEMICAL EQUILIBRIUMS IN WO3–H2O SYSTEM

2017 ◽  
pp. 35-48 ◽  
Author(s):  
V.P. Bondarenko ◽  
O.O. Matviichuk
Keyword(s):  
Transition Temperature ◽  
Gas Phase ◽  
Single Phase ◽  
Reference Data ◽  
Maximum Amount ◽  
Reaction Products ◽  
Influence Of Temperature ◽  
Equilibrium Chemical ◽  
Program Data ◽  
Good Agreement

Detail investigation of equilibrium chemical reactions in WO3–H2O system using computer program FacktSage with the aim to establish influence of temperature and quantity of water on formation of compounds of H2WO4 and WO2(OH)2 as well as concomitant them compounds, evaporation products, decomposition and dissociation, that are contained in the program data base were carried out. Calculations in the temperature range from 100 to 3000 °С were carried out. The amount moles of water added to 1 mole of WO3 was varied from 0 to 27. It is found that the obtained data by the melting and evaporation temperatures of single-phase WO3 are in good agreement with the reference data and provide additionally detailed information on the composition of the gas phase. It was shown that under heating of 1 mole single-phase WO3 up to 3000 °С the predominant oxide that exist in gaseous phase is (WO3)2. Reactions of it formation from other oxides ((WO3)3 and (WO3)4) were proposed. It was established that compound H2WO4 is stable and it is decomposed on WO3 and H2O under 121 °C. Tungsten Oxide Hydrate WO2(OH)2 first appears under 400 °С and exists up to 3000 °С. Increasing quantity of Н2О in system leads to decreasing transition temperature of WO3 into both liquid and gaseous phases. It was established that adding to 1 mole WO3 26 mole H2O maximum amount (0,9044–0,9171 mole) WO2(OH)2 under temperatures 1400–1600 °С can be obtained, wherein the melting stage of WO3 is omitted. Obtained data also allowed to state that that from 121 till 400 °С WO3–Н2O the section in the О–W–H ternary system is partially quasi-binary because under these temperatures in the system only WO3 and Н2O are present. Under higher temperatures WO3–Н2O section becomes not quasi-binary since in the reaction products WO3 with Н2O except WO3 and Н2O, there are significant amounts of WO2(OH)2, (WO3)2, (WO3)3, (WO3)4 and a small amount of atoms and other compounds. Bibl. 12, Fig. 6, Tab. 5.

The Coherence of Mary Barton: Romance, Realism, and Utopia

2015 ◽  
Vol 5 (3) ◽  
pp. 185-200
Author(s):  
Robert Z. Birdwell
Keyword(s):  
Thomas Carlyle ◽  
The Novel ◽  
Second Stage ◽  
The Third ◽  
Third Stage ◽  
Three Stages ◽  
Mode Of Production

Critics have argued that Elizabeth Gaskell's first novel, Mary Barton (1848), is split by a conflict between the modes of realism and romance. But the conflict does not render the novel incoherent, because Gaskell surpasses both modes through a utopian narrative that breaks with the conflict of form and gives coherence to the whole novel. Gaskell not only depicts what Thomas Carlyle called the ‘Condition of England’ in her work but also develops, through three stages, the utopia that will redeem this condition. The first stage is romantic nostalgia, a backward glance at Eden from the countryside surrounding Manchester. The second stage occurs in Manchester, as Gaskell mixes romance with a realistic mode, tracing a utopian drive toward death. The third stage is the utopian break with romantic and realistic accounts of the Condition of England and with the inadequate preceding conceptions of utopia. This third stage transforms narrative modes and figures a new mode of production.

How well do voice-hearing assessment measures capture the positive experiences of individuals?

2019 ◽  
Author(s):  
Lucy Armstrong ◽  
Lorna Hogg ◽  
Pamela Charlotte Jacobsen
Keyword(s):  
Systematic Review ◽  
Lived Experience ◽  
Second Stage ◽  
The Third ◽  
Third Stage ◽  
Hearing Assessment ◽  
Positive Experiences ◽  
Assessment Measures ◽  
Stage 1 ◽  
The Voice

The first stage of this project aims to identify assessment measures which include items on voice-hearing by way of a systematic review. The second stage is the development of a brief framework of categories of positive experiences of voice hearing, using a triangulated approach, drawing on views from both professionals and people with lived experience. The third stage will involve using the framework to identify any positve aspects of voice-hearing included in the voice hearing assessments identified in stage 1.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

scholarly journals When the World Breaks Down: A 3-Stage Existential Model of Nihilism in Schizophrenia

2021 ◽  
pp. 1-24
Author(s):  
Philipp Klar ◽  
Georg Northoff
Keyword(s):  
The Self ◽  
First Person ◽  
Second Stage ◽  
Existential Crisis ◽  
Third Stage ◽  
The World ◽  
Third Person ◽  
Pathological Development ◽  
Sense Of Reality ◽  
Intentional Structure

The existential crisis of nihilism in schizophrenia has been reported since the early days of psychiatry. Taking first-person accounts concerning nihilistic experiences of both the self and the world as vantage point, we aim to develop a dynamic existential model of the pathological development of existential nihilism. Since the phenomenology of such a crisis is intrinsically subjective, we especially take the immediate and pre-reflective first-person perspective’s (FPP) experience (instead of objectified symptoms and diagnoses) of schizophrenia into consideration. The hereby developed existential model consists of 3 conceptualized stages that are nested into each other, which defines what we mean by existential. At the same time, the model intrinsically converges with the phenomenological concept of the self-world structure notable inside our existential framework. Regarding the 3 individual stages, we suggest that the onset or first stage of nihilistic pathogenesis is reflected by phenomenological solipsism, that is, a general disruption of the FPP experience. Paradigmatically, this initial disruption contains the well-known crisis of common sense in schizophrenia. The following second stage of epistemological solipsism negatively affects all possible perspectives of experience, that is, the first-, second-, and third-person perspectives of subjectivity. Therefore, within the second stage, solipsism expands from a disruption of immediate and pre-reflective experience (first stage) to a disruption of reflective experience and principal knowledge (second stage), as mirrored in abnormal epistemological limitations of principal knowledge. Finally, the experience of the annihilation of healthy self-consciousness into the ultimate collapse of the individual’s existence defines the third stage. The schizophrenic individual consequently loses her/his vital experience since the intentional structure of consciousness including any sense of reality breaks down. Such a descriptive-interpretative existential model of nihilism in schizophrenia may ultimately serve as input for future psychopathological investigations of nihilism in general, including, for instance, its manifestation in depression.

The Origins of the Village Revisited: From Nuclear to Extended Households

2002 ◽  
Vol 67 (3) ◽  
pp. 417-433 ◽  
Author(s):  
Kent V. Flannery
Keyword(s):  
Nuclear Family ◽  
Extended Family ◽  
Near East ◽  
Shared Storage ◽  
Nuclear Families ◽  
Second Stage ◽  
Third Stage ◽  
Two Stages ◽  
Extended Households ◽  
The Village

In Mesoamerica and the Near East, the emergence of the village seems to have involved two stages. In the first stage, individuals were distributed through a series of small circular-to-oval structures, accompanied by communal or “shared” storage features. In the second stage, nuclear families occupied substantial rectangular houses with private storage rooms. Over the last 30 years a wealth of data from the Near East, Egypt, the Trans-Caucasus, India, Africa, and the Southwest U.S. have enriched our understanding of this phenomenon. And in Mesoamerica and the Near East, evidence suggests that nuclear family households eventually gave way to a third stage, one featuring extended family households whose greater labor force made possible extensive multifaceted economies.

Reconstruction of Tragus and External Auditory Meatus using Remnant Auricle during Microtia Reconstruction

2018 ◽  
Vol 34 (02) ◽  
pp. 227-229
Author(s):  
Yi-gao Hu ◽  
Wei Ding ◽  
Jun Tan ◽  
Xin Chen ◽  
Tao Luo ◽  
...  
Keyword(s):  
Skin Flap ◽  
Skin Grafting ◽  
External Auditory Meatus ◽  
Reconstruction Technique ◽  
External Ear ◽  
Flap Necrosis ◽  
Second Stage ◽  
The Third ◽  
Third Stage ◽  
Thin Skin

AbstractThis article investigates an effective method with which to reconstruct the tragus and external auditory meatus for microtia reconstruction. The external ear was reconstructed using a delayed postauricular skin flap in patients with congenital microtia. After the first stage of delaying the postauricular skin flap and the second stage of otoplasty with ear framework fabricated from autogenous rib cartilage draping with the delayed skin flap, the third stage involved tragus and external auditory meatus canaloplasty. After designing the remnant auricle flap, the lower part was trimmed and the tragus was reconstructed. The upper part was trimmed into a thin skin flap, which was rotated and used to cover the hollowed wound posterosuperior to the tragus so as to mimic the external auditory meatus. If remnant wounds were present, skin grafting was conducted. In total, 121 patients with congenital microtia were treated from March 2010 to March 2016. The reconstructed tragus and external auditory meatus were well formed, and all wounds healed well. No severe complications such as flap necrosis occurred. Six months postoperatively, the morphology of the reconstructed tragus and external auditory meatus was good. Overall, the patients and their families were satisfied. The use of remnant auricle to reconstruct the tragus and external auditory meatus is an effective auricular reconstruction technique.

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