A Kinetic Study of the C49 to C54 Conversion in TiSi2 Using Electrical Resistivity Measurements on Single Sub-Micron Lines

1995 ◽  
Vol 402 ◽  
Author(s):  
K. L. Saenger ◽  
C. Cabral ◽  
L. A. Clevenger ◽  
R. A. Roy
Keyword(s):  
Nucleation Site ◽  
Avrami Equation ◽  
Nucleation Density ◽  
Time Behavior ◽  
Site Density ◽  
Defect Sites ◽  
Kinetics Of ◽  
Nucleation Site Density ◽  
Individual Line

AbstractA simple, quasi-in situ resistivity technique was used to examine the C49 to C54 conversion kinetics of TiSi2 on sub-micron (0.2 to 1.1 μm) line structures formed in a self-aligned silicide (salicide) process. This technique was used to examine both aggregate conversion vs. time behavior and individual-line conversion vs. time behavior as a function of linewidth and polysilicon doping. As linewidth decreased, aggregate conversion vs. time at temperature behavior slowed, and the conversion behaviors shown by nominally identical lines became more variable. Four line behaviors were identified on the narrowest lines: short incubation/prompt conversion, gradual conversion, incomplete conversion, and no conversion. These behaviors are compared to those predicted by the Avrami equation, and to those predicted for a nucleation-site-density controlled reaction under conditions of low nucleation density. It is suggested that C49-C54 conversion in narrow lines may be primarily limited not by the number of C54 nucleation events, but by the presence of randomly occurring line-edge “defect” sites which slow and/or halt C54 grain growth.

Kinetics of agglomeration of NiSi and NiSi2 phase formation.

2002 ◽  
Vol 745 ◽  
Author(s):  
C. Detavernier ◽  
A. Özcan ◽  
C. Lavoie ◽  
Jean-Jordan Sweet ◽  
J. M. E. Harper
Keyword(s):  
Phase Formation ◽  
Nucleation Site ◽  
Silicon On Insulator ◽  
X Ray Diffraction ◽  
Heating Rates ◽  
Site Density ◽  
Device Applications ◽  
Higher Temperature ◽  
Kinetics Of

ABSTRACTWe have studied the kinetics of NiSi agglomeration and NiSi2 phase formation during heating of NiSi on Si, using simultaneous in situ measurements of resistance, light scattering and x-ray diffraction. NiSi is a desirable contact to Si because of its low resistivity, limited Si consumption and low formation temperature. However, the formation of the higher resistivity phase NiSi2 must be avoided for device applications. Ni thin films 5 to 30 nm thick were deposited on substrates of poly-Si and silicon-on-insulator (SOI) and were studied using heating rates from 0.3 to 27 °C/s. At low heating rates and for the thinnest films studied, NiSi agglomeration precedes NiSi2 nucleation by as much as 350°C. The agglomeration temperature decreases with decreasing film thickness and linewidth. Once the film is agglomerated, the formation of NiSi2 is delayed to higher temperature by its low nucleation site density and decreased contact area. We conclude that agglomeration is the primary failure mechanism limiting the morphological stability of NiSi as a contact material to Si devices.

scholarly journals Morphology and crystallization kinetics of Rubber-modified Nylon 6 Prepared by Anionic In-situ Polymerization

2020 ◽  
Vol 27 (1) ◽  
pp. 204-215
Author(s):  
Hongkai Zhao ◽  
Dengchao Zhang ◽  
Yingshuang Li
Keyword(s):  
Crystallization Kinetics ◽  
In Situ Polymerization ◽  
Good Description ◽  
Nylon 6 ◽  
Avrami Equation ◽  
Infrared Analysis ◽  
Chain Segment ◽  
The Impact ◽  
Kinetics Of

AbstractIn this work, we modified nylon 6 with liquid rubber by in-situ polymerization. The infrared analysis suggested that HDI urea diketone is successfully blocked by caprolactam after grafting on hydroxyl of HTPB, and the rubber-modified nylon copolymer is generated by the anionic polymerization. The impact section analysis indicated the rubber-modified nylon 6 resin exhibited an alpha crystal form.With an increase in the rubber content, nylon 6 was more likely to generate stable α crystal. Avrami equation was a good description of the non-isothermal crystallization kinetics of nylon-6 and rubber-modified nylon-6 resin. Moreover, it is found that the initial crystallization temperature of nylon-6 chain segment decreased due to the flexible rubber chain segment. n value of rubber-modified nylon-6 indicated that its growth was the coexistence of two-dimensional discoid and three-dimensional spherulite growth. Finally, the addition of the rubber accelerated the crystallization rate of nylon 6.

scholarly journals CNN-based visual analysis to study local boiling characteristics

2021 ◽  
Vol 2119 (1) ◽  
pp. 012068
Author(s):  
A N Chernyavskiy ◽  
I P Malakhov
Keyword(s):  
Network Architecture ◽  
High Speed ◽  
Visual Analysis ◽  
Nucleation Site ◽  
High Speed Video ◽  
Site Density ◽  
Segmentation Approach ◽  
Nucleation Site Density ◽  
Instance Segmentation

Abstract Visual analysis allows an estimate of different local boiling characteristics including bubble growth rate, departure diameters and frequencies of nucleation, nucleation site density and evolution of bubbles and dry spots in time. At the same time, visual determination of the presented characteristics in case of big amounts of data requires the development of the appropriate software which will allow not only determination of bubble location, but also an estimate of their sizes based on high-speed video. The presented problem can be solved by using the instance segmentation approach based on a convolutional neural network. In the presented work Mask R-CNN network architecture was used for estimation of the local boiling characteristics.

An Experimental Study of Boiling Heat Transfer During Quenching of Nanofluids With Carbon Nanotubes of Various Sizes

2016 ◽  
Author(s):  
Jia-Qi Li ◽  
Li-Wu Fan ◽  
Liang Zhang ◽  
Zi-Tao Yu
Keyword(s):  
Carbon Nanotubes ◽  
Heat Flux ◽  
Surface Roughness ◽  
Initial Temperature ◽  
Nucleation Site ◽  
Transient Temperature ◽  
Porous Layers ◽  
Site Density ◽  
Nucleation Site Density ◽  
Walled Cnts

Quenching experiments were performed with hot stainless steel spheres in a pool of water-based nanofluids in the presence of carbon nanotubes (CNTs) of various sizes. In order to explore the size effect, a test matrix was developed by choosing multi-walled CNTs with lengths from 1 μm to 5 μm and outer diameters from 30 nm to 60 nm. The concentration was fixed at 0.5% by mass for all types of CNTs. The initial temperature was 400 °C and the transient temperature variations at the center of the sphere were recorded as quenching curves. By establishing a lumped capacitance model, the transient surface heat flux variations were obtained as boiling curves. The original and boiled surfaces were both subjected to a series of characterizations to determine the changes in morphology, roughness, and wettability to identify the effects of CNT size on the surface properties of the formed deposition layers as well as to elucidate the mechanisms for regulation of the boiling and quenching behaviors. The results suggested that the critical heat flux (CHF) and the Leidenfrost point (LFP) are enhanced to various degrees due to the discrepancy in the size of the CNTs in nanofluids. It was shown that the CNTs deposited on the surfaces create various morphologies depending on their size. The CNTs with a length of 5 μm and a diameter of 60 nm exhibited the most significant effect on the boiling behaviors. In comparison to CNTs with a shorter length of 1 μm, the 5 μm long CNTs were much easier to form porous layers. The results of the contact angle and roughness tests showed that the porous layers tend to affect the surface roughness instead of surface wettability. The increases of the nucleation site density and surface roughness due to the presence of porous layers were identified as the primary cause for the modified boiling behaviors during quenching.

Creation of Nano-Scaled Surface Structure for the Enhancement of Boiling Heat Transfer

2004 ◽  
Author(s):  
Sho Ngai ◽  
A. I. Leontiev ◽  
John R. Lloyd ◽  
S. P. Malyshenko
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Nucleation Site ◽  
Glancing Angle Deposition ◽  
Surface Structures ◽  
Transfer Enhancement ◽  
Site Density ◽  
Glancing Angle ◽  
Angle Deposition ◽  
Nucleation Site Density

The present research is an experimental investigation of nucleate pool boiling heat transfer enhancement on a surface with micro/nano-scaled surface structures. Glancing Angle Deposition (GLAD) was employed to fabricate porous surfaces in this study. The thin film microstructure consists of closely packed columns oriented in the plane of incidence formed due to a self-shadowing mechanism. Boiling heat transfer from the nano-structured surface was compared to that of a smooth reference surface and the commercial High Flux surface. The results of this study have shown that nano-structured films created by the GLAD process increase the nucleation site density as compared to the smooth surface. This research has opened up new areas in the field of heat transfer, which motivate new surface coating concepts to enhance the understanding of boiling heat transfer on nano-structured films.

Comparison of Gas Nucleation and Pool Boiling Site Densities

2004 ◽  
Author(s):  
Yusen Qi ◽  
James F. Klausner
Keyword(s):  
Heat Transfer ◽  
Stainless Steel ◽  
Pool Boiling ◽  
Nucleation Site ◽  
Nucleation Theory ◽  
Distilled Water ◽  
General Validity ◽  
Site Density ◽  
Steel Surfaces ◽  
Nucleation Site Density

It has been well established that the rate of heat transfer associated with boiling systems is strongly dependent on the nucleation site density. Over many years attempts have been made to predict nucleation site density in boiling systems using a variety of techniques. With the exception of specially prepared surfaces, these attempts have met with little success. This paper presents an experimental investigation of nucleation site density measured on roughly polished brass and stainless steel surfaces for gas nucleation and pool boiling over a large parameter space. The fluids used for this study, distilled water and ethanol, are moderately wetting and highly wetting, respectively. Using distilled water it has been observed that the trends of nucleation site density versus the inverse of the critical radius are similar for pool boiling and gas nucleation. The nucleation site density is higher for gas nucleation than for pool boiling. An unexpected result has been observed with ethanol as the heat transfer fluid, which casts doubt on the general validity of heterogeneous nucleation theory. Due to flooding, few sites are active on the brass surface and at most two are active on the stainless steel surface during gas nucleation experiments. However, nucleation sites readily form in large concentration on both the brass and stainless steel surfaces during pool boiling. The nucleation site densities for the rough and mirror polished brass surfaces are also compared. It shows that there is no large difference for the measured nucleation site density.

Control of nucleation site density of GaN nanowires

2007 ◽  
Vol 253 (6) ◽  
pp. 3196-3200 ◽  
Author(s):  
Chih-Yang Chang ◽  
S.J. Pearton ◽  
Ping-Jung Huang ◽  
Gou-Chung Chi ◽  
Hung-Ta Wang ◽  
...  
Keyword(s):  
Nucleation Site ◽  
Gan Nanowires ◽  
Site Density ◽  
Nucleation Site Density

Island Formation of SiC Film on Striated Si(001) Substrates

2008 ◽  
Vol 600-603 ◽  
pp. 227-230 ◽  
Author(s):  
Yoshimine Kato ◽  
Kazuo Sakumoto
Keyword(s):  
Growth Rate ◽  
Film Growth ◽  
Nucleation Site ◽  
The Other ◽  
Film Growth Rate ◽  
Surface Nucleation ◽  
Site Density ◽  
Other Hand ◽  
Sic Film ◽  
Nucleation Site Density

SiC growth on as-received and striated Si(001) substrates was studied. SiC films were grown by pulsed-jet chemical vapor deposition using monomethylsilane as a gas source at 780°C. Two kinds of Si surfaces were prepared. One was an as-received Si(001) surface and the other was an striated (scratched) Si(001) surface. It was found that nucleation rate of SiC is quite different between these two kinds of surfaces. The film growth rate was very low for the as-received Si(001) surface compared with the striated surface, and after 8 hours of growth hardly any film was grown and only square-shaped islands were observed. On the other hand, for the undulant substrate about 100nm thick 3C-SiC film was grown after 8 hours of deposition. This film growth rate difference appears to be due to the difference in density of nucleation sites. For the as-received Si(001) surface, nucleation site density appears to be quite small due to the atomically flat surface. On the other hand, for the undulant surface, nucleation site density was large enough for the film to grow faster.

Sign in / Sign up

Export Citation Format

Share Document