scholarly journals A Percolative Approach to Reliability of Thin Film Interconnects and Ultra-thin Dielectrics

VLSI Design ◽  
2001 ◽  
Vol 13 (1-4) ◽  
pp. 363-367
Author(s):  
C. Pennetta ◽  
L. Reggiani ◽  
Gy. Trefán ◽  
R. Cataldo ◽  
G. De Nunzio
Keyword(s):  
Thin Film ◽  
Steady State ◽  
Stochastic Approach ◽  
Physical Parameters ◽  
Two Dimensional ◽  
Steady State Condition ◽  
Random Resistor Network ◽  
Resistor Network ◽  
Thin Dielectrics ◽  
Unified Description

Degradation of thin film interconnects and ultra-thin dielectrics is studied within a stochastic approach based on a percolation technique. The thin film is modelled as a two-dimensional random resistor network at a given temperature and its degradation is characterized by a breaking probability of the single resistor. A recovery of the damage is also allowed so that a steady-state condition can be achieved. The main features of experiments are reproduced. This approach provides a unified description of degradation and failure processes in terms of physical parameters.

Numerical study of electric field effects on the deformation of two-dimensional liquid drops in simple shear flow at arbitrary Reynolds number

2009 ◽  
Vol 626 ◽  
pp. 367-393 ◽  
Author(s):  
STEFAN MÄHLMANN ◽  
DEMETRIOS T. PAPAGEORGIOU
Keyword(s):  
Steady State ◽  
Shear Flow ◽  
Electric Field ◽  
Electric Fields ◽  
Simple Shear ◽  
Simple Shear Flow ◽  
Physical Parameters ◽  
Shear Stresses ◽  
Two Dimensional ◽  
Liquid Drops

The effect of an electric field on a periodic array of two-dimensional liquid drops suspended in simple shear flow is studied numerically. The shear is produced by moving the parallel walls of the channel containing the fluids at equal speeds but in opposite directions and an electric field is generated by imposing a constant voltage difference across the channel walls. The level set method is adapted to electrohydrodynamics problems that include a background flow in order to compute the effects of permittivity and conductivity differences between the two phases on the dynamics and drop configurations. The electric field introduces additional interfacial stresses at the drop interface and we perform extensive computations to assess the combined effects of electric fields, surface tension and inertia. Our computations for perfect dielectric systems indicate that the electric field increases the drop deformation to generate elongated drops at steady state, and at the same time alters the drop orientation by increasing alignment with the vertical, which is the direction of the underlying electric field. These phenomena are observed for a range of values of Reynolds and capillary numbers. Computations using the leaky dielectric model also indicate that for certain combinations of electric properties the drop can undergo enhanced alignment with the vertical or the horizontal, as compared to perfect dielectric systems. For cases of enhanced elongation and alignment with the vertical, the flow positions the droplets closer to the channel walls where they cause larger wall shear stresses. We also establish that a sufficiently strong electric field can be used to destabilize the flow in the sense that steady-state droplets that can exist in its absence for a set of physical parameters, become increasingly and indefinitely elongated until additional mechanisms can lead to rupture. It is suggested that electric fields can be used to enhance such phenomena.

Experimental Validation of Towed Underwater Cable Model

2019 ◽  
Author(s):  
Jan Vidar Grindheim ◽  
Antonio Carlos Fernandes ◽  
Joel Sena Sales Junior ◽  
Inge Revhaug
Keyword(s):  
Steady State ◽  
Experimental Validation ◽  
Experimental Results ◽  
Experimental Setup ◽  
Two Dimensional ◽  
Cable Model ◽  
Governing Equations ◽  
Current Channel ◽  
Steady State Condition ◽  
Wet Weight

Abstract Towed underwater cable models have been validated using experimental results performed in the current channel at Laboratório de Ondas e Correntes (LOC) at COPPE/UFRJ, Rio de Janeiro. The numerical simulators utilize a Finite Difference Method to solve the Partial Differential Equations describing the dynamics of a towed underwater cable under tension. A non-dimensional analysis of the system dynamics for the two-dimensional case has been performed, with non-dimensional governing equations being presented. The experimental setup consists of two cable sections of ∼1.5 m length each, the first having 3 mm diameter and slightly positive wet weight while the second section has 2.5 mm diameter and slight negative wet weight. With the cable in steady-state condition, the towpoint is moved 0.50 m sideways and the time for the cable to return to straight tow is measured. Further, the cable depths at midpoint and tail are measured in steady-state. Experiments are performed at currents ranging from 0.17 to 0.47 m/s. The presented experimental results are compared to the numerical results. Reasonable agreements are obtained.

A numerical study of the motion of drops in Poiseuille flow. Part 1. Lateral migration of one drop

2000 ◽  
Vol 411 ◽  
pp. 325-350 ◽  
Author(s):  
SAEED MORTAZAVI ◽  
GRÉTAR TRYGGVASON
Keyword(s):  
Reynolds Number ◽  
Steady State ◽  
Poiseuille Flow ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Lateral Position ◽  
Physical Parameters ◽  
Computational Domain ◽  
Two Dimensional ◽  
Lateral Migration

The cross-stream migration of a deformable drop in two-dimensional Hagen–Poiseuille flow at finite Reynolds numbers is studied numerically. In the limit of a small Reynolds number (< 1), the motion of the drop depends strongly on the ratio of the viscosity of the drop fluid to the viscosity of the suspending fluid. For viscosity ratio 0.125 a drop moves toward the centre of the channel, while for ratio 1.0 it moves away from the centre until halted by wall repulsion. The rate of migration increases with the deformability of the drop. At higher Reynolds numbers (5–50), the drop either moves to an equilibrium lateral position about halfway between the centreline and the wall – according to the so-called Segre–Silberberg effect or it undergoes oscillatory motion. The steady-state position depends only weakly on the various physical parameters of the flow, but the length of the transient oscillations increases as the Reynolds number is raised, or the density of the drop is increased, or the viscosity of the drop is decreased. Once the Reynolds number is high enough, the oscillations appear to persist forever and no steady state is observed. The numerical results are in good agreement with experimental observations, especially for drops that reach a steady-state lateral position. Most of the simulations assume that the flow is two-dimensional. A few simulations of three-dimensional flows for a modest Reynolds number (Re = 10), and a small computational domain, confirm the behaviour seen in two dimensions. The equilibrium position of the three-dimensional drop is close to that predicted in the simulations of two-dimensional flow.

Current distributions in a two-dimensional random-resistor network

1992 ◽  
Vol 67 (1-2) ◽  
pp. 113-121 ◽  
Author(s):  
E. Duering ◽  
R. Blumenfeld ◽  
D. J. Bergman ◽  
A. Aharony ◽  
M. Murat
Keyword(s):  
Two Dimensional ◽  
Random Resistor Network ◽  
Resistor Network ◽  
Current Distributions

Two-Dimensional Heat Transfer Considerations for Thermoreflectance Measurements

2018 ◽  
Author(s):  
Dipta Sarkar ◽  
Partha Pratim Chakraborty ◽  
B. Terry Beck ◽  
Zayd C. Leseman
Keyword(s):  
Steady State ◽  
Heat Equation ◽  
Continuous Wave ◽  
Dirichlet Boundary Conditions ◽  
Transient Condition ◽  
Neumann Condition ◽  
Two Dimensional ◽  
Laser Beam Intensity ◽  
Steady State Condition ◽  
Dimensional Approximation

In the Suspended ThermoReflectance (STR) technique a microcantilever is heated with a laser power at the free end of the microcantilever and as heat propagates through it, another laser is used to measure the temperature along the beam.[1] In this paper, the heat equation is solved for two-dimensional heat flow in the microcantilever to determine the material’s thermal conductivity and heat capacity. Two of the dimensions of the microcantilever, width and length, are significantly greater than the third dimension, the thickness, leading to the two-dimensional approximation. Two boundaries along the length of the structure and one boundary along the width are assumed to be under Dirichlet boundary conditions, while the other boundary has Neumann condition. The Neumann or flux condition has a Gaussian profile due to the nature of laser beam intensity. The heat equation is solved using under 3 different flux conditions: (1) Steady-state, (2) Transient, and (3) Periodic. A steady-state condition mimics the experimental condition when a continuous wave laser is used to heat the microcantilever’s tip. A transient condition is possible when quickly removing or adding the continuous wave laser’s flux from the microcantilever’s tip using a chopper. Finally, a periodic condition can be achieved when an electro-optic modulator is utilized experimentally. Closed form analytical expressions are evaluated against the finite element model and experimental results for microcantilever beams and micro-structures of Si that have lengths on the order of a mm, width on the order of 100 microns, and thicknesses of 1 micron or less.

Studies on Water in the Hydration Chamber of a Modified Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 544-545
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electron Microscope ◽  
Steady State ◽  
Room Temperature ◽  
Small Mass ◽  
Equilibrium Pressure ◽  
Biological Objects ◽  
Mechanical Pump ◽  
Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

Two-dimensional BN-doped ZnO thin-film deposition by a thermionic vacuum arc system

2020 ◽  
Vol 31 (9) ◽  
pp. 6948-6955
Author(s):  
Mustafa Özgür ◽  
Suat Pat ◽  
Reza Mohammadigharehbagh ◽  
Uğur Demirkol ◽  
Nihan Akkurt ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Vacuum Arc ◽  
Zno Thin Film ◽  
Two Dimensional ◽  
Doped Zno ◽  
Thermionic Vacuum Arc

scholarly journals Computational Performance of Disparate Lattice Boltzmann Scenarios under Unsteady Thermal Convection Flow and Heat Transfer Simulation

Computation ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 65
Author(s):  
Aditya Dewanto Hartono ◽  
Kyuro Sasaki ◽  
Yuichi Sugai ◽  
Ronald Nguele
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Natural Convection ◽  
Lattice Boltzmann ◽  
Numerical Results ◽  
Convection And Heat Transfer ◽  
Steady State Condition ◽  
Physical Systems ◽  
Flow And Heat Transfer ◽  
Computational Performance

The present work highlights the capacity of disparate lattice Boltzmann strategies in simulating natural convection and heat transfer phenomena during the unsteady period of the flow. Within the framework of Bhatnagar-Gross-Krook collision operator, diverse lattice Boltzmann schemes emerged from two different embodiments of discrete Boltzmann expression and three distinct forcing models. Subsequently, computational performance of disparate lattice Boltzmann strategies was tested upon two different thermo-hydrodynamics configurations, namely the natural convection in a differentially-heated cavity and the Rayleigh-Bènard convection. For the purposes of exhibition and validation, the steady-state conditions of both physical systems were compared with the established numerical results from the classical computational techniques. Excellent agreements were observed for both thermo-hydrodynamics cases. Numerical results of both physical systems demonstrate the existence of considerable discrepancy in the computational characteristics of different lattice Boltzmann strategies during the unsteady period of the simulation. The corresponding disparity diminished gradually as the simulation proceeded towards a steady-state condition, where the computational profiles became almost equivalent. Variation in the discrete lattice Boltzmann expressions was identified as the primary factor that engenders the prevailed heterogeneity in the computational behaviour. Meanwhile, the contribution of distinct forcing models to the emergence of such diversity was found to be inconsequential. The findings of the present study contribute to the ventures to alleviate contemporary issues regarding proper selection of lattice Boltzmann schemes in modelling fluid flow and heat transfer phenomena.

Influence of ion beam parameters onto two-dimensional optical thin film thickness distributions deposited by ion beam sputtering

2019 ◽  
Vol 682 ◽  
pp. 109-120 ◽  
Author(s):  
Wjatscheslaw Sakiew ◽  
Stefan Schrameyer ◽  
Marco Jupé ◽  
Philippe Schwerdtner ◽  
Nick Erhart ◽  
...  
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Ion Beam ◽  
Two Dimensional ◽  
Ion Beam Sputtering ◽  
Thin Film Thickness ◽  
Optical Thin Film ◽  
Beam Sputtering ◽  
Beam Parameters
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