scholarly journals Mechanism of Electronegativity Heterojunction of Nanometer Amorphous-Boron on Crystalline Silicon: An Overview

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 108
Author(s):  
Paolo Sberna ◽  
Piet X. Fang ◽  
Changming Fang ◽  
Stoyan Nihtianov
Keyword(s):  
Crystalline Silicon ◽  
Chemical Vapor ◽  
Amorphous Boron ◽  
Research Directions ◽  
Highly Sensitive ◽  
Low Energy Electrons ◽  
Unique Nature ◽  
History Of ◽  
Microelectronics Industry ◽  
Ultraviolet Photons

The discovery of the extremely shallow amorphous boron-crystalline silicon heterojunction occurred during the development of highly sensitive, hard and robust detectors for low-penetration-depth ionizing radiation, such as ultraviolet photons and low-energy electrons (below 1 keV). For many years it was believed that the junction created by the chemical vapor deposition of amorphous boron on n-type crystalline silicon was a shallow p-n junction, although experimental results could not provide evidence for such a conclusion. Only recently, quantum-mechanics based modelling revealed the unique nature and the formation mechanism of this new junction. Here, we review the initiation and the history of understanding the a-B/c-Si interface (henceforth called the “boron-silicon junction”), as well as its importance for the microelectronics industry, followed by the scientific perception of the new junctions. Future developments and possible research directions are also discussed.

Surface Processes in CVD: Laser- and Low Energy Electron-Induced Decomposition of W(CO)6 on Si(111)-(7×7)

1988 ◽  
Vol 131 ◽  
Author(s):  
Cynthia M. Friend ◽  
J. R. Swanson ◽  
F. A. Flitsch
Keyword(s):  
Chemical Vapor ◽  
Electron Bombardment ◽  
Low Energy ◽  
Limiting Factor ◽  
Thermally Induced ◽  
Low Energy Electrons ◽  
Ultraviolet Photolysis ◽  
Temperature Programmed ◽  
Ultraviolet Photons ◽  
Temperature Programmed Reaction

ABSTRACTThe decomposition of W(CO)6 adsorbed on Si(111)-(7×7) using low energy electrons and ultraviolet photons has been investigated under ultrahigh vacuum conditions. This work is motivated by a desire to understand the mechanism for laser- and electron-assisted chemical vapor deposition (CVD) of tungsten using volatile coordination complexes and to specifically understand the role of the surface in these processes. Both electron stimulated and photo-assisted decomposition of the adsorbed W(CO)6 are observed. No thermal decomposition of the W(CO)6 occurs under the conditions of these experiments, based on independent temperature programmed reaction experiments, ruling out the possibility of laser- or electron-induced heating as the cause of decomposition. Furthermore, the interaction of the W(CO)6 with the Si(111)-(7×7) surface is shown to be exceedingly weak based on the fact that the desorption energy is 9.46 ± 0.77 kcal/mol. Desorption of CO is induced during both ultraviolet photolysis and electron bombardment. Carbon monoxide is exclusively evolved during ultraviolet photolysis: no W-containing fragments are desorbed. During electron bombardment, a small amount of the W(CO)6 is desorbed, accounting for ∼10% of the desorption. In both cases, CO-containing W fragments remain on the surface after decomposition at low surface temperature. The remaining surface fragments do not undergo further photolysis at 308 nm but do react thermally. Competing desorption and dissociation of CO are thermally induced resulting in carbide and oxide impurities in the deposited material. The fact that strongly bound W(CO)x fragments are trapped on the surface is proposed as a limiting factor in the purity of tungsten deposits using the decomposition of W(CO)6.

The SiNx films process research by plasma-enhanced chemical vapor deposition in crystalline silicon solar cells

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744101 ◽  
Author(s):  
Bitao Chen ◽  
Yingke Zhang ◽  
Qiuping Ouyang ◽  
Fei Chen ◽  
Xinghua Zhan ◽  
...  
Keyword(s):  
Thin Film ◽  
Chemical Vapor Deposition ◽  
Solar Cell ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Silicon Solar Cell ◽  
Crystalline Silicon ◽  
Chemical Vapor ◽  
Double Layers ◽  
Crystalline Silicon Solar Cell

SiNx thin film has been widely used in crystalline silicon solar cell production because of the good anti-reflection and passivation effect. We can effectively optimize the cells performance by plasma-enhanced chemical vapor deposition (PECVD) method to change deposition conditions such as temperature, gas flow ratio, etc. In this paper, we deposit a new layer of SiNx thin film on the basis of double-layers process. By changing the process parameters, the compactness of thin films is improved effectively. The NH3passivation technology is augmented in a creative way, which improves the minority carrier lifetime. In sight of this, a significant increase is generated in the photoelectric performance of crystalline silicon solar cell.

The Properties Of a-Si:H/c-Si Heterostructures Prepared By 55 kHz Pecvd For Solar Cell Application

1997 ◽  
Vol 485 ◽  
Author(s):  
B. G Budaguan ◽  
A. A. Aivazov ◽  
A. A. Sherchenkov ◽  
A. V Blrjukov ◽  
V. D. Chernomordic ◽  
...  
Keyword(s):  
Crystalline Silicon ◽  
Low Frequency ◽  
Reverse Current ◽  
Chemical Vapor ◽  
Interface State ◽  
State Density ◽  
Solar Cell Application ◽  
Current Voltage ◽  
Frequency Plasma ◽  
Device Applications

AbstractIn this work a-Si:H/c-Si heterostructures with good electronic properties of a-Si:H were prepared by 55 kHz Plasma Enhanced Chemical Vapor Deposition (PECVD). Currentvoltage and capacitance-voltage characteristics of a-Si:H/c-Si heterostructures were measuredto investigate the influence of low frequency plasma on the growing film and amorphous silicon/crystalline silicon boundary. It was established that the interface state density is low enough for device applications (<2.1010 cm−2). The current voltage measurements suggest that, when forward biased, space-charge-limited current determines the transport mechanism in a- Si:H/c-Si heterostructures, while reverse current is ascribed to the generation current in a-Si:H and c-Si depletion layers.

Influence of Technical Parameters on the Residual Stress in the Diamond Coating

2012 ◽  
Vol 426 ◽  
pp. 85-88
Author(s):  
Hong Xiang Wang ◽  
Dun Wen Zuo ◽  
Chun Xu ◽  
Chun Zhou
Keyword(s):  
Residual Stress ◽  
Substrate Temperature ◽  
Compressive Stress ◽  
Crystalline Silicon ◽  
Volume Ratio ◽  
Chemical Vapor ◽  
Chamber Pressure ◽  
Diamond Coating ◽  
Diamond Coatings ◽  
Technical Parameters

The diamond coatings were prepared by hot filament chemical vapor deposition(HFCVD) on the mono-crystalline silicon substrates. The influence of the technical parameters such as methane volume ratio, substrate temperature and reaction pressure on the residual stress in the diamond coating was studied. The results showed that the residual stress in the coating was compressive stress in the range of parameters studied, and too high or too low substrate temperature, chamber pressure and methane volume ratio would all increase the residual compressive stress. This relationship can be explained by the influence of amorphous carbon content, vacancy density and grain size on the residual stress.

MEMS Post-Packaging by Localized Heating

2000 ◽  
Author(s):  
Liwei Lin
Keyword(s):  
Vapor Deposition ◽  
Microelectromechanical Systems ◽  
Chemical Vapor ◽  
Research Subject ◽  
Major Research ◽  
Research Directions ◽  
Mems Packaging ◽  
Fusion Bonding ◽  
Localized Heating ◽  
Pressure Chemical

Abstract This work addresses important post-packaging issues for microelectromechanical systems (MEMS) and introduces specific research directions by means of localized heating and bonding. MEMS packaging has become a major research subject due to the stringent packaging requirements in the emerging filed of MEMS. Establishing a versatile post-packaging process not only advances the field scientifically but also helps product commercialization in industry. An innovative post-packaging approach by localized heating and bonding is proposed and presented in this paper. Various post-packaging processes are demonstrated, including an integrated LPCVD (Low Pressure Chemical Vapor Deposition) sealing process, localized silicon-gold eutectic bonding, localized silicon-glass fusion bonding, localized solder bonding and localized CVD bonding processes.

Myeloid Sarcoma of the Head and Neck Region

2013 ◽  
Vol 137 (11) ◽  
pp. 1560-1568 ◽  
Author(s):  
Jane Zhou ◽  
Diana Bell ◽  
L. Jeffrey Medeiros
Keyword(s):  
Head And Neck ◽  
Low Frequency ◽  
Neck Region ◽  
Immunohistochemical Analysis ◽  
Myeloid Sarcoma ◽  
Head And Neck Region ◽  
Bone Marrow Disease ◽  
Highly Sensitive ◽  
History Of ◽  
High Degree

Context.—Myeloid sarcoma of the head and neck region can pose diagnostic challenges because of the low frequency of myeloid sarcoma and the potential for tumors of almost any lineage to occur in the head and neck. Objective.—To study the clinicopathologic and immunohistochemical characteristics of myeloid sarcoma in the head and neck region and to review the differential diagnosis. Design.—We searched for cases of myeloid sarcoma involving the head and neck region for a 24-year period at our institution. The medical records and pathology slides were reviewed. Additional immunohistochemical stains were performed. Results.—We identified 17 patients, age 17 to 85 years. Most tumors involved the oral cavity. Myeloid sarcoma was the initial diagnosis in 9 patients (53%); the remaining 8 patients (47%) had a history of bone marrow disease. Immunohistochemical analysis using antibodies specific for lysozyme, CD43, and CD68 were highly sensitive for diagnosis but were not specific. By contrast, assessment for myeloperoxidase in this study was less sensitive but more specific. We also used antibodies specific for CD11c and CD33 in a subset of cases, and these reagents seem helpful as well. Conclusions.—The clinical presentation of myeloid sarcoma involving the head and neck, particularly the mouth, is often nonspecific, and a high degree of suspicion for the possibility of myeloid sarcoma is needed. Immunohistochemistry is very helpful for establishing the diagnosis.

Effects of long-term protection from grazing on phenotypic expression in geographically separated mountain rough fescue populations

2014 ◽  
Vol 94 (1) ◽  
pp. 33-39 ◽  
Author(s):  
D. J. Thompson ◽  
W. D. Willms
Keyword(s):  
Plant Communities ◽  
Phenotypic Expression ◽  
Highly Sensitive ◽  
History Of ◽  
Genetic Makeup ◽  
Rough Fescue ◽  
Geographic Sources ◽  
Lake Site ◽  
Summer Grazing

Thompson, D. J. and Willms, W. D. 2014. Effects of long-term protection from grazing on phenotypic expression in geographically separated mountain rough fescue populations. Can. J. Plant Sci. 94: 33–39. Whether or not long-term grazing or protection from grazing alters the genetic makeup of grass populations has been debated. Mountain rough fescue [(Festuca campestris (Rydb.)], which is highly sensitive to summer grazing, and becomes dominant in plant communities with long-term protection, was chosen to address this question. Plants from three geographic sites (Stavely in AB, Milroy in the Kootenay trench, BC and Goose Lake on the BC interior plateau) with divergent grazing histories were vegetatively propagated from tillers. Daughter plants were planted into two field nurseries (at Kamloops, BC, and Stavely, AB) and morphological measurements were taken in two field seasons post-establishment. Plants from all three populations were taller, flowered earlier, and were more productive at the Kamloops nursery site. Of the three geographic sources, plants from the Goose Lake site were most distinct with narrower leaves, later flowering, and greater yield. Plants with a long history of grazing had slightly shorter fertile tillers and leaves than plants with a history of long-term protection.

Achieving High Nucleation Density of Diamond Film Under Low Pressures in Hot-Filament Chemical Vapor Deposition

1994 ◽  
Vol 363 ◽  
Author(s):  
Yan Chen ◽  
Jun Mei ◽  
Qijin Chen ◽  
Zhangda Lin
Keyword(s):  
Chemical Vapor Deposition ◽  
Diamond Film ◽  
Vapor Deposition ◽  
Crystalline Silicon ◽  
Chemical Vapor ◽  
Nucleation Density ◽  
Heteroepitaxial Growth ◽  
Hot Filament ◽  
Low Pressures ◽  
Gaseous Source

AbstractDiamond have been deposited rapidly under low pressures (<0.1 Torr) via hot filament chemical vapor deposition (HFCVD) on either scratched or mirror-smooth single crystalline silicon and titanium with nucleation densities of 109–1011/cm2. The nucleation density increases with the pressure decreases. Hydrogen and methane were used as the gaseous source. Raman spectroscopy and scanning electron microscopy(SEM) were used to analyze the obtained films. This result breaks through the limit that diamond film can only be synthesized above 10 Torr, showing a promising prospect that, as is essential for heteroepitaxial growth of monocrystalline diamond films, diamond film can be easily nucleated on unscratched substrate via Hot Filament CVD.

scholarly journals Surface passivation and optical characterization of Al2O3/a-SiCx stacks on c-Si substrates

2013 ◽  
Vol 4 ◽  
pp. 726-731 ◽  
Author(s):  
Gema López ◽  
Pablo R Ortega ◽  
Cristóbal Voz ◽  
Isidro Martín ◽  
Mónica Colina ◽  
...  
Keyword(s):  
Wavelength Range ◽  
Surface Passivation ◽  
Crystalline Silicon ◽  
Surface Recombination ◽  
Chemical Vapor ◽  
Optical Characterization ◽  
Surface Recombination Velocity ◽  
Carrier Injection ◽  
Si Substrates

The aim of this work is to study the surface passivation of aluminum oxide/amorphous silicon carbide (Al2O3/a-SiCx) stacks on both p-type and n-type crystalline silicon (c-Si) substrates as well as the optical characterization of these stacks. Al2O3 films of different thicknesses were deposited by thermal atomic layer deposition (ALD) at 200 °C and were complemented with a layer of a-SiCx deposited by plasma-enhanced chemical vapor deposition (PECVD) to form anti-reflection coating (ARC) stacks with a total thickness of 75 nm. A comparative study has been carried out on polished and randomly textured wafers. We have experimentally determined the optimum thickness of the stack for photovoltaic applications by minimizing the reflection losses over a wide wavelength range (300–1200 nm) without compromising the outstanding passivation properties of the Al2O3 films. The upper limit of the surface recombination velocity (S eff,max) was evaluated at a carrier injection level corresponding to 1-sun illumination, which led to values below 10 cm/s. Reflectance values below 2% were measured on textured samples over the wavelength range of 450–1000 nm.

scholarly journals Everyday Things Change: Australian Athlete Communication During the Coronavirus Lockdown

2020 ◽  
Vol 13 (3) ◽  
pp. 541-550
Author(s):  
Lewis Whales ◽  
Stephen Frawley ◽  
Adam Cohen ◽  
Natalia Nikolova
Keyword(s):  
Ethnographic Study ◽  
Professional Sport ◽  
Physical Interaction ◽  
Research Directions ◽  
Geographical Separation ◽  
History Of ◽  
Stakeholder Communication

During the coronavirus (COVID-19) pandemic, Australian professional sport leagues were impacted by temporary league shutdowns. One example is the Suncorp Super Netball, the world’s premier netball competition. This commentary paper explores the Suncorp Super Netball league shutdown from the perspective of the players. Our commentary has emerged from an ongoing ethnographic study supported by interviews with two players (a representative on the players association and a club captain) conducted during the league shutdown. Such a shutdown was the first in the history of the league, and it required an unprecedented response, coordinated by interdependent stakeholders. The authors outlined the importance of stakeholder communication in effectively navigating this extraordinary situation. In addition, the authors discussed the usefulness of technology-as-context for teamwork and leadership, given the limitations on physical interaction and geographical separation. In conclusion, the authors proposed recommendations for sport practitioners and potential research directions resulting from the coronavirus-related league shutdown.

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