Analysis of Si-SiO2 Interfacial-Energy Hierarchy via Mixed-Phase Solidification of Si Films on SiO2

2015 ◽  
Vol 1770 ◽  
pp. 55-60
Author(s):  
Ying Wang ◽  
Monica D. Chahal ◽  
J. J. Wang ◽  
A. B. Limanov ◽  
A. M. Chitu ◽  
...  
Keyword(s):  
Partial Melting ◽  
Microstructure Evolution ◽  
Interfacial Energy ◽  
Thermodynamic Model ◽  
Orientation Distribution ◽  
Mixed Phase ◽  
Hierarchical Order ◽  
Interfacial Energies ◽  
Si Films ◽  
Melting And Solidification

ABSTRACTWe have experimentally investigated the anisotropy of Si-SiO2 interfacial energy by leveraging the mixed-phase solidification (MPS) method. By examining the microstructure evolution resulting from partial-melting-and-solidification cycles, and interpreting the changes in the surface-orientation distribution of the grains in terms of the thermodynamic model, we have identified the orientation-dependent hierarchical order of Si-SiO2 interfacial energies, σ{hkl}, as: σ{100} < σ{310} < σ{113} < σ{112} < σ{221} < σ{210}∼σ{331} < σ{111}, σ{110}.

Effect of Film Thickness Variation on (100)-Surface Texturing of MPS Processed Polycrystalline Si Films

2012 ◽  
Vol 1426 ◽  
pp. 257-262 ◽  
Author(s):  
Monica Chahal ◽  
P. C. van der Wilt ◽  
D. Van Gestel ◽  
A. B. Limanov ◽  
A. M. Chitu ◽  
...  
Keyword(s):  
Film Thickness ◽  
Thermodynamic Model ◽  
Surface Texturing ◽  
Thickness Variation ◽  
Interfacial Energies ◽  
Anisotropic Solid ◽  
Interface Curvature ◽  
Si Films ◽  
Solid Liquid Interface ◽  
Solid Liquid

ABSTRACTWe have investigated the effect of varying the film thickness on the surface orientation texturing in polycrystalline Si films obtained via mixed-phase solidification (MPS) of initially a-Si precursor films on SiO2. It is found that, for a given number of MPS exposure cycles, the degree of (100)-surface texturing is reduced as the film thickness is increased. We discuss how this trend can be accounted for by the previously proposed thermodynamic model of MPS, wherein a decreasing local solid/liquid interface curvature with increasing film thickness is identified as the primary cause for decreasing the influence which anisotropic solid-Si/SiO2 interfacial energies have on the survivability of the grains. This, in turn, leads to other factors becoming more significant in determining the grains that survive the MPS cycle, thereby reducing the degree of (100)-surface texturing in the resulting films.

Excimer-Laser-Induced Melting and Solidification of PECVD a-Si films under Partial-Melting Conditions

2011 ◽  
Vol 1321 ◽  
Author(s):  
Q. Hu ◽  
Catherine S. Lee ◽  
T. Li ◽  
Y. Deng ◽  
U.J. Chung ◽  
...  
Keyword(s):  
Partial Melting ◽  
Pulsed Laser ◽  
Solidification Behavior ◽  
Fine Grained ◽  
Melting Regime ◽  
Si Films ◽  
Experimental Findings ◽  
Defective Crystal ◽  
Moving Liquid ◽  
Melting And Solidification

ABSTRACTThis paper reports on new experimental findings and conclusions regarding the pulsed-laser-induced melting-and-solidification behavior of PECVD a-Si films. The experimental findings reveal that, within the partial-melting regime, these a-Si films can melt and solidify in ways that are distinct from, and more complex than, those encountered in microcrystalline-cluster-rich LPCVD a-Si films. Specifically (1) spatially dispersed and temporally stochastic nucleation of crystalline solids occurring relatively effectively at the moving liquid-amorphous interface, (2) very defective crystal growth that leads to the formation of fine-grained Si proceeding, at least initially after the nucleation, at a sufficiently rapidly moving crystal solidification front, and (3) the propensity for local preferential remelting of the defective regions and grain boundaries (while the beam is still on) are identified as being some of the fundamental factors that can participate and affect how these PECVD films melt and solidify.

scholarly journals Optimization of Interfacial Energy for Langer-Schwartz Based Precipitation Simulations

2021 ◽  
Author(s):  
Conner Sarich ◽  
Adam Hope ◽  
Jim Rule
Keyword(s):  
Experimental Data ◽  
Interfacial Energy ◽  
Volume Fraction ◽  
Published Data ◽  
Low Alloy Steels ◽  
Interfacial Energies ◽  
Nucleation Sites ◽  
Alloy Steels ◽  
Thermal Histories ◽  
Al 2024

Abstract Precipitation kinetics were investigated in select Fe, Ni, and Al alloys using a CALPHAD based precipitation model based on Langer-Schwartz theory. Thermodynamic and kinetic data are taken from commercially available CALPHAD software, but reliable interfacial energy data for precipitates needed for the calculations is often lacking. While models exist to approximate these interfacial energies, this study has focused on deriving more reliable estimates by comparison with experimental data. By performing simulations with thermal histories, nucleation sites, and precipitate morphologies that closely replicate experimental data found in literature, the interfacial energies were optimized until volume fraction and mean radius values closely matched the published data. Using this technique, interfacial energy values have been determined for carbides in Grade 22 low alloy steels, delta phase in Ni 625 and 718, SPhase in Al 2024, and Q’ and β’’ in Al 6111, and can be used for future predictive precipitation simulations.

scholarly journals Adhesive interactions of geckos with wet and dry fluoropolymer substrates

2015 ◽  
Vol 12 (108) ◽  
pp. 20150464 ◽  
Author(s):  
Alyssa Y. Stark ◽  
Daniel M. Dryden ◽  
Jeffrey Olderman ◽  
Kelly A. Peterson ◽  
Peter H. Niewiarowski ◽  
...  
Keyword(s):  
Surface Energy ◽  
Interfacial Energy ◽  
Substrate Surface ◽  
Energy Calculations ◽  
Bioinspired Design ◽  
Interfacial Energies ◽  
Normal Adhesion ◽  
Adhesive Interactions ◽  
Low Shear

Fluorinated substrates like Teflon ® (poly(tetrafluoroethylene); PTFE) are well known for their role in creating non-stick surfaces. We showed previously that even geckos, which can stick to most surfaces under a wide variety of conditions, slip on PTFE. Surprisingly, however, geckos can stick reasonably well to PTFE if it is wet. In an effort to explain this effect, we have turned our attention to the role of substrate surface energy and roughness when shear adhesion occurs in media other than air. In this study, we removed the roughness component inherent to commercially available PTFE and tested geckos on relatively smooth wet and dry fluoropolymer substrates. We found that roughness had very little effect on shear adhesion in air or in water and that the level of fluorination was most important for shear adhesion, particularly in air. Surface energy calculations of the two fluorinated substrates and one control substrate using the Tabor–Winterton approximation and the Young–Dupré equation were used to determine the interfacial energy of the substrates. Using these interfacial energies we estimated the ratio of wet and dry normal adhesion for geckos clinging to the three substrates. Consistent with the results for rough PTFE, our predictions show a qualitative trend in shear adhesion based on fluorination, and the quantitative experimental differences highlight the unusually low shear adhesion of geckos on dry smooth fluorinated substrates, which is not captured by surface energy calculations. Our work has implications for bioinspired design of synthetics that can preferentially stick in water but not in air.

Numerical analysis of excimer-laser-induced melting and solidification of thin Si films

1997 ◽  
Vol 71 (1) ◽  
pp. 99-101 ◽  
Author(s):  
Vikas V. Gupta ◽  
H. Jin Song ◽  
James S. Im
Keyword(s):  
Numerical Analysis ◽  
Excimer Laser ◽  
Si Films ◽  
Melting And Solidification

Preparation of Semi-Solid Billet with Less Liquid Content of 7A09 Aluminum Alloy by Partial-Melting Method

2009 ◽  
Vol 79-82 ◽  
pp. 1795-1798
Author(s):  
Wei Wei Wang ◽  
Jian Li Song ◽  
Jing Bo Yu
Keyword(s):  
Aluminum Alloy ◽  
Optical Microscopy ◽  
Partial Melting ◽  
Microstructure Evolution ◽  
Processing Parameters ◽  
Liquid Content ◽  
Melting Method ◽  
Wide Range ◽  
Fine Microstructure ◽  
Semi Solid

Preparation of semi-solid microstructure with less liquid content of 7A09 aluminum alloy industrial extrusion billets is studied in this paper. In the treatment, melting-stirring and predeformation of the alloy billets are not required. The influences of different heating temperatures and insulation time on the microstructure evolution are studied and the obtained microstructure is observed and analyzed by optical microscopy. The results indicate that a fine microstructure can be obtained with the proposed process and the processing parameters can be controlled over a wide range. The liquid content can be controlled within a certain range.

Size-Dependent Equilibrium Shapes of Solid Pb Inclusions in Al

1997 ◽  
Vol 3 (S2) ◽  
pp. 629-630
Author(s):  
U. Dahmen ◽  
E. Johnson ◽  
S.Q. Xiao ◽  
S. Paciornik ◽  
A. Johansen
Keyword(s):  
Size Dependence ◽  
Equilibrium Shape ◽  
Alloy System ◽  
Lattice Parameter ◽  
Al Alloys ◽  
Size Dependent ◽  
Interfacial Energies ◽  
Relative Extent ◽  
Equilibrium Shapes ◽  
Melting And Solidification

Small Pb inclusions in Al have been studied by a number of investigators because the alloy system offers the possibility of observing the processes of melting and solidification directly. Both solids are fee, and the mutual solubility of solid Pb and Al is negligible. Despite a large difference in lattice parameter, it has been found that inclusions follow a parallel-cube orientation relationship and their equilibrium shape is a cuboctahedron, bounded by ﹛111﹜ and ﹛100﹜ facets [1]. Following Herring, the relative extent of the two types of facet directly indicates a ratio of interfacial energies γl00/γ111- However, recent investigations have shown that for inclusions in the range of a few to a few tens of nanometers the equilibrium shape becomes a function of size [2].In the present work, this size dependence of the equilibrium shape has been investigated further. Al alloys with about lat.% Pb were prepared by rapid solidification or by ion implantation, and equilibrated by annealing at about 300°C.

scholarly journals Layer Inversion of Ni(Pt)Si on Mixed Phase Si Films

2002 ◽  
Vol 5 (3) ◽  
pp. G15 ◽  
Author(s):  
P. S. Lee ◽  
K. L. Pey ◽  
D. Mangelinck ◽  
J. Ding ◽  
T. Osipowicz ◽  
...  
Keyword(s):  
Mixed Phase ◽  
Si Films

scholarly journals Structure of mixed-phase Si films studied by C-AFM and X-TEM

2007 ◽  
Vol 61 ◽  
pp. 790-794
Author(s):  
T Mates ◽  
P C P Bronsveld ◽  
A Fejfar ◽  
B Rezek ◽  
J Kočka ◽  
...  
Keyword(s):  
Mixed Phase ◽  
Si Films
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