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.

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}.

An Anomalous Elastohydrodynamic Lubrication Film: Inlet Dimple

2005 ◽  
Vol 127 (2) ◽  
pp. 425-434 ◽  
Author(s):  
F. Guo ◽  
P. L. Wong
Keyword(s):  
Shear Stress ◽  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Lubrication Film ◽  
Entrainment Velocity ◽  
Limiting Shear Stress ◽  
The Individual ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Wall Slippage

This paper presents a deliberately designed elastohydrodynamical lubrication (EHL) experiment for the study of the individual effect of the limiting shear stress and wall slippage. Very slow entrainment speeds were employed to avoid influential shear heating and oils of high viscosities were chosen to ensure that the conjunction was under typical EHL. An anomalous EHL film, characterized by a dimple at the inlet region, was obtained. Literature revealed that this inlet dimple was reported in some numerical studies taking into consideration the limiting-shear-stress characteristics of the lubricant and wall slippage. It was found that even under the same kinematic conditions, different types of film shape would be generated by simple disc sliding and simple ball sliding. Simple disc sliding produces an inlet dimple with a comparatively thick inlet film thickness, which droops rapidly toward the outlet region. For simple ball sliding, there is also an inlet dimple but the central film thickness is rather uniform. However, by prerunning the conjunction at a zero entrainment velocity (at the same linear speeds but in opposite directions) before the sliding experiment, the slope of the central film of simple disc sliding becomes smaller. It is probably due to the modification of solid-liquid interface, i.e., the slippage level, by the highly pressurized and stressed prerunning conditions. With a prescribed prerunning, which can produce very similar films at simple disc sliding and simple ball sliding, variation of film thickness was studied and it was found that the inlet dimple film has obvious dependence on entrainment speeds, but was not sensitive to loads. The present experimental results can be considered as direct evidence for those numerical findings of the inlet dimple. Tentatively, an effective viscosity wedge is proposed to account for the formation of the inlet dimple.

Effects of the Interface Curvature and Dendrite Orientation in Directional Solidification of Bulk Transparent Alloys

2006 ◽  
Vol 508 ◽  
pp. 337-342 ◽  
Author(s):  
Cedric Weiss ◽  
Nathalie Bergeon ◽  
Nathalie Mangelinck-Noël ◽  
Bernard Billia
Keyword(s):  
Directional Solidification ◽  
Optical Methods ◽  
Fundamental Physics ◽  
Materials Engineering ◽  
Interface Curvature ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Selection Of

The properties of structural materials are to a large extent determined by the solid microstructure so that the understanding of the fundamental physics of microstructure formation is critical in the field of materials engineering. A directional solidification facility dedicated to the characterization of solid-liquid interface morphology by means of optical methods has been developed by CNES in the frame of the DECLIC project. This device enables in situ and real time studies on bulk transparent materials. The aim of the project is to perform experiments in microgravity to eliminate the complex couplings between solidification and convection and to get reliable benchmark data to validate and calibrate theoretical modeling and numerical simulations. Presently, ground experiments are performed to finalize the design and the experimental procedures and to guarantee the accuracy of the measurements. These experiments also provide reference data for the study of solidification microstructure dynamics in the presence of buoyancy-driven natural convection. Recent progress is presented concerning the control of the interface shape (critical for pattern analysis), the selection of single crystal of defined orientation (critical for dendritic growth) and the analysis of the dendrite shape.

A Cellular Automaton Model with the Lower Mesh-Induced Anisotropy for Dendritic Solidification of Pure Substance

2010 ◽  
Vol 654-656 ◽  
pp. 1528-1531 ◽  
Author(s):  
Xin Lin ◽  
Lei Wei ◽  
Meng Wang ◽  
Wei Dong Huang
Keyword(s):  
Cellular Automaton ◽  
Dendritic Growth ◽  
Cellular Automaton Model ◽  
Pure Substance ◽  
Dendritic Solidification ◽  
Induced Anisotropy ◽  
Interface Curvature ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Interfacial Energy Anisotropy

A modified cellular automaton model for describing the dendritic solidification of pure substance was developed. Instead of using the high mesh-induced anisotropy capture rules, such as Von Neumann’s and Moore’s method, a new capture rule---random zigzag method was developed, which greatly reduced the mesh-induced anisotropy in crystallographic orientation. The calculation method for the solid/liquid interface curvature was also improved. The effect of interfacial energy anisotropy on the dendritic growth behavior was analyzed.

Numerical Modeling of Energy-Beam Induced Localized Melting of Thin SI Films

1989 ◽  
Vol 157 ◽  
Author(s):  
J.S. Im ◽  
W J.D. Lipman ◽  
I.N. Miaoulis ◽  
C.K. Chenb ◽  
C.V. Thompson
Keyword(s):  
Quantitative Information ◽  
Quantitative Model ◽  
Liquid Interface ◽  
Phase Changes ◽  
Physical Factors ◽  
Conductive Heat ◽  
Energy Beam ◽  
Si Films ◽  
Solid Liquid Interface ◽  
Solid Liquid

ABSTRACTWe have developed a quantitative model, based on a two-dimensional finite difference enthalpy method, which accounts for the localized melting behavior of thin Si films on substrates. The model incorporates radiative and conductive heat flow components and takes account of the phase changes that occur during zone-melting recrystallization. Emphasis is placed on the effects resulting from the differences in reflectivity and emissivity between solid and liquid Si. The model provides quantitative information concerning the temperature profile of the Si film and the configuration of the solid-liquid interface. Results of the analysis indicate that there exist two distinct types of transition behavior: i) reflectivity-change dominated and ii) emissivity-change dominated. Partial melting and a nonplanar solid-liquid interface are characteristics of the reflectivity-change dominated behavior. The emissivity-change dominated behavior, on the other hand, can be characterized by explosive-like melting and a planar solid-liquid interface. The conditions and physical factors which give rise to these behaviors are discussed.

A Boundary Value Model for an Evaporating Meniscus

2010 ◽  
Author(s):  
Arya Chatterjee ◽  
Joel L. Plawsky ◽  
Peter C. Wayner
Keyword(s):  
Heat Transfer ◽  
Boundary Conditions ◽  
Contact Line ◽  
Effective Means ◽  
Line Region ◽  
Hydrodynamic Slip ◽  
Interface Curvature ◽  
Solid Liquid Interface ◽  
Value Model ◽  
Solid Liquid

The constrained vapor bubble (CVB) experiment is an experiment to study the effect of low Bond numbers on the microscopic and macroscopic transport in a heat pipe. The microscopic (∼30 μm) contact line region, where the solid, liquid and vapor phase meet, is of fundamental importance in this study of fluid flow and heat transfer. This region, while dominated by interfacial forces, is controlled by the boundary conditions set by physics at the macroscopic scale (∼1 mm) on one side and the microscopic scale (∼ 0.1 μm) on the other. Recent experimental investigation by our group has shown that an effective means of changing the microscopic boundary conditions (the wettability of the fluid) is by introducing surface roughness at the nanoscale to the solid surface. Here we attempt to examine some of the experimental results in the light of a model. The model solves a nonlinear, fourth order evolution equation for the film thickness. It also provides the contact angle, interface curvature and heat transfer profile in the contact line region. The model agrees well with the experimental data. The presence of hydrodynamic slip at the solid liquid interface seems to improve the agreement.

Effect of Pulling Rate on Multicrystalline Silicon Ingot during Directional Solidification

2011 ◽  
Vol 675-677 ◽  
pp. 53-56 ◽  
Author(s):  
Shi Hai Sun ◽  
Yi Tan ◽  
Hui Xing Zhang ◽  
Wei Dong ◽  
Jun Shan Zhang ◽  
...  
Keyword(s):  
Directional Solidification ◽  
Constitutional Supercooling ◽  
Multicrystalline Silicon ◽  
Segregation Coefficient ◽  
Silicon Ingot ◽  
Interface Curvature ◽  
Effective Segregation Coefficient ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Effective Segregation

In this paper, the structure and composition of multicrystalline silicon ingots prepared by directional solidification with different pulling rates were analyzed to investigate the effect of pulling rate on the multicrystalline silicon ingot. The results showed that the lower pulling rate will make the site taking place constitutional supercooling move to the upper part of ingots and make the high purity area become larger. Lowering the pulling rate will decrease the impurity effective segregation coefficient and the solid-liquid interface curvature.

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