Modified Line-of-Sight Model for Deposition of Tungsten Silicide Barrier Layers

1990 ◽  
Vol 181 ◽  
Author(s):  
Timothy S. Cale ◽  
Gregory B. Raupp
Keyword(s):  
Qualitative Agreement ◽  
Quantitative Agreement ◽  
Reaction Model ◽  
Experimental Results ◽  
Diffusion Reaction ◽  
Line Of Sight ◽  
Tungsten Silicide ◽  
Barrier Layers ◽  
Nominal Thickness ◽  
Model Predictions

ABSTRACTA modified line-of-sight model for transport and deposition during LPCVD is used to predict step coverage and film composition uniformity of tungsten silicide barrier layers. Predictions are compared with experimental results for 2 μim wide by 6 μm deep trenches with barrier layers of 0.2 μm nominal thickness. Model predictions are in quantitative agreement with those of a diffusion-reaction model and are in qualitative agreement with experiment.

Deposition of Tungsten Silicide Barrier Layers and Tungsten in Rectangular Vias

1990 ◽  
Vol 181 ◽  
Author(s):  
Timothy S. Cale ◽  
Gregory B. Raupp ◽  
Manoj K. Jain
Keyword(s):  
Hydrogen Reduction ◽  
Low Pressure ◽  
Diffusion Reaction ◽  
High Deposition Rate ◽  
Tungsten Silicide ◽  
Step Process ◽  
Barrier Layers ◽  
Tungsten Hexafluoride ◽  
Selection Of ◽  
Pressure Hydrogen

ABSTRACTDiffusion-reaction analysis of a two step process in which a tungsten silicide barrier layer is deposited in a rectangular trench by low pressure dichlorosilane reduction of tungsten hexafluoride followed by a complete tungsten fill by low pressure hydrogen reduction of tungsten hexafluoride reveals that high step coverage and high deposition rate can be readily achieved with logical selection of process parameters. This fact, coupled with the potential for accomplishing these deposition steps in the same single wafer reactor, suggests that this two step process may offer a high throughput alternative to blanket tungsten deposition by silane reduction.

scholarly journals A Diffusion-Reaction Model for Predicting Enzyme-Mediated Dynamic Hydrogel Stiffening

Gels ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 17 ◽  
Author(s):  
Hung-Yi Liu ◽  
Chien-Chi Lin
Keyword(s):  
Cell Fate ◽  
Diffusion Path ◽  
Reaction Model ◽  
Tissue Mechanics ◽  
Diffusion Reaction ◽  
Factors Affecting ◽  
Model Predictions ◽  
Tunable Mechanical Properties ◽  
The Impact ◽  
Hydrogel System

Hydrogels with spatiotemporally tunable mechanical properties have been increasingly employed for studying the impact of tissue mechanics on cell fate processes. These dynamic hydrogels are particularly suitable for recapitulating the temporal stiffening of a tumor microenvironment. To this end, we have reported an enzyme-mediated stiffening hydrogel system where tyrosinase (Tyrase) was used to stiffen orthogonally crosslinked cell-laden hydrogels. Herein, a mathematical model was proposed to describe enzyme diffusion and reaction within a highly swollen gel network, and to elucidate the critical factors affecting the degree of gel stiffening. Briefly, Fick’s second law of diffusion was used to predict enzyme diffusion in a swollen poly(ethylene glycol) (PEG)-peptide hydrogel, whereas the Michaelis–Menten model was employed for estimating the extent of enzyme-mediated secondary crosslinking. To experimentally validate model predictions, we designed a hydrogel system composed of 8-arm PEG-norbornene (PEG8NB) and bis-cysteine containing peptide crosslinker. Hydrogel was crosslinked in a channel slide that permitted one-dimensional diffusion of Tyrase. Model predictions and experimental results suggested that an increasing network crosslinking during stiffening process did not significantly affect enzyme diffusion. Rather, diffusion path length and the time of enzyme incubation were more critical in determining the distribution of Tyrase and the formation of additional crosslinks in the hydrogel network. Finally, we demonstrated that the enzyme-stiffened hydrogels exhibited elastic properties similar to other chemically crosslinked hydrogels. This study provides a better mechanistic understanding regarding the process of enzyme-mediated dynamic stiffening of hydrogels.

The Double Excitation of Helium by Electron Impact

1935 ◽  
Vol 31 (4) ◽  
pp. 604-608 ◽  
Author(s):  
H. S. W. Massey ◽  
C. B. O. Mohr
Keyword(s):  
Electron Impact ◽  
Qualitative Agreement ◽  
Quantitative Agreement ◽  
Experimental Results ◽  
Angular Distributions ◽  
Double Excitation ◽  
Doubly Excited

The probability of excitation of helium by electron impact to the more important doubly excited levels is calculated, and comparison made with the experimental results of Priestley and Whiddington who have observed two lines due to double excitation. The calculated relative intensities and angular distributions are found to be in qualitative agreement with experiment, and reasons are given for the lack of quantitative agreement.

scholarly journals Researching on the Deterministic Channel Models for Urban Microcells Considering Diffraction Effects

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2143
Author(s):  
Chunzhi Hou ◽  
Zhensen Wu ◽  
Jiaji Wu ◽  
Yunhua Cao ◽  
Leke Lin ◽  
...  
Keyword(s):  
Millimeter Wave ◽  
Wireless Channel ◽  
Experimental Results ◽  
Line Of Sight ◽  
Diffraction Effect ◽  
Channel Models ◽  
Wave Channel ◽  
Channel Parameters ◽  
Diffraction Effects ◽  
Ray Launching

Deterministic channel models, such as the three-dimensional (3D) ray launching method, can yield wireless channel parameters. In the non-line-of-sight (NLOS) propagation, the outdoor 3D ray launching method that considers diffraction effects is more accurate than the one that does not. While considering the diffraction effect, obtaining the diffraction point is challenging. This paper proposed a method for determining diffracted rays using the receiving sphere method in 3D ray launching. The diffraction point is determined using the shortest distance method between two straight lines, and the signal loss from the transmitting to receiving antennas is obtained. Furthermore, experiments on a millimeter wave in a microcell scenario were performed. The test results of the wireless channel parameters were compared with theoretical calculations. The results obtained via the 3D ray launching method that only considers the specular reflection and direct rays agree with the experimental results in the line-of-sight (LOS); furthermore, they generate larger errors compared with the experimental results in the NLOS. The results obtained via the 3D ray launching method that considers the direct ray, reflected rays, and diffracted rays agree with the experimental results both in the LOS and NLOS. Therefore, the 3D ray launching method that considers the diffraction effect can improve the prediction accuracy of the millimeter wave channel parameters in a microcell.

scholarly journals A permeation-diffusion-reaction model of gas transport in cellular tissue of plant materials

2006 ◽  
Vol 57 (15) ◽  
pp. 4215-4224 ◽  
Author(s):  
Q. T. Ho ◽  
B. E. Verlinden ◽  
P. Verboven ◽  
S. Vandewalle ◽  
B. M. Nicolai
Keyword(s):  
Gas Transport ◽  
Cellular Tissue ◽  
Reaction Model ◽  
Diffusion Reaction ◽  
Plant Materials

Diffusion-reaction model for ASR

2014 ◽  
pp. 639-648 ◽  
Author(s):  
J Liaudat ◽  
C López ◽  
I Carol
Keyword(s):  
Reaction Model ◽  
Diffusion Reaction

scholarly journals An Indoor AC Magnetic Positioning System

2021 ◽  
Author(s):  
Paolo Carbone ◽  
Guido De Angelis ◽  
Valter Pasku ◽  
Alessio De Angelis ◽  
Marco Dionigi ◽  
...  
Keyword(s):  
Indoor Environment ◽  
Indoor Positioning ◽  
Experimental Results ◽  
System Level ◽  
Line Of Sight ◽  
Positioning System ◽  
Positioning Error ◽  
Geometric Configurations ◽  
Indoor Positioning System ◽  
Non Line Of Sight

<div><div><div><p>This paper describes the design and realization of a Magnetic Indoor Positioning System. The system is entirely realized using off-the-shelf components and is based on inductive coupling between resonating coils. Both system-level architecture and realization details are described along with experimental results. The realized system exhibits a maximum positioning error of less than 10 cm in an indoor environment over a 3×3 m2 area. Extensive experiments in larger areas, in non-line-of-sight conditions, and in unfavorable geometric configurations, show sub-meter accuracy, thus validating the robustness of the system with respect to other existing solutions.</p></div></div></div>

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