Dislocation Dynamics in Semiconductor Thin Film-Substrate Systems

2003 ◽  
Vol 795 ◽  
Author(s):  
E. H. Tan ◽  
L. Z. Sun
Keyword(s):  
Thin Film ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Film Surface ◽  
Dislocation Dynamics ◽  
Dislocation Loops ◽  
Discrete Dislocation ◽  
Specific Shape ◽  
Semiconductor Thin Film ◽  
Film Substrate

ABSTRACTA discrete dislocation dynamics model is developed to establish the equations of motion for three-dimensional interacting dislocation loops in the semiconductor thin film – substrate system. The film is assumed to be an elastic layer and is perfectly bonded with another elastic substrate. Dislocation loops are discretized into segments, each of which is represented by a parametric space curve of specific shape functions and associated degree of freedom. The dislocation stress field is calculated as an essential ingredient in the dislocation dynamics method. Dislocation dynamics and interaction with film surface/interface are simulated.

3D Discrete Dislocation Models Of Thin-Film Plasticity

1997 ◽  
Vol 505 ◽  
Author(s):  
A. Hartmaier ◽  
M. C. Fivel ◽  
G. R. Canova ◽  
P. Gumbsch
Keyword(s):  
Thin Film ◽  
Three Dimensional ◽  
Dislocation Dynamics ◽  
Normal Stresses ◽  
Bulk Materials ◽  
Free Standing ◽  
Discrete Dislocation Dynamics ◽  
Discrete Dislocation ◽  
Dislocation Models ◽  
Dimensional Simulation

ABSTRACTThree-dimensional simulation schemes for discrete dislocation dynamics (DDD) have been used successfully to investigate plasticity of bulk materials. The adaptation of these DDD schemes to a description of thin-film plasticity requires detailed modeling of the interfaces and surfaces of the film. One possible method is to compensate for the normal stresses that a dislocation distribution exerts on a surface by appropriate point loads. This traction-compensation method is extended to a free standing film (two opposing surfaces). The extension to a thin film on a substrate is possible.

Exotic Doping for Zno Thin Films: Possibility of Monolithic Optical Integrated Circuit

1999 ◽  
Vol 574 ◽  
Author(s):  
Norifumi Fujimura ◽  
Tamaki Shimura ◽  
Toshifumi Wakano ◽  
Atsushi Ashida ◽  
Taichiro Ito
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Nonlinear Optic ◽  
Integrated Circuit ◽  
Film Surface ◽  
Zno Thin Films ◽  
Process Window ◽  
Electro Optic ◽  
Film Substrate ◽  
Optical Integrated Circuit

AbstractWe propose the application of ZnO:X (X = Li, Mg, N, In, Al, Mn, Gd, Yb etc.) films for a monolithic Optical Integrated Circuit (OIC). Since ZnO exhibits excellent piezoelectric effect and has also electro-optic and nonlinear optic effects and the thin films are easily obtained, it has been studied as one of the important thin film wave guide materials especially for an acoustooptic device[1]. In terms of electro-optic and nonlinear optic effects, however, LiNbO3 or LiTaO3 is superior to ZnO. The most important issue of thin film waveguide using such ferroelectrics is optical losses at the film/substrate interface and the film surface, because the process window to control the surface morphology is very narrow due to their high deposition temperature. Since ZnO can be grown at extremely low temperature, the roughness at the surface and the interface is expected to be minimized. This is the absolute requirement especially for waveguide using a blue or ultraviolet laser. Recently, lasing at the wavelength of ultraviolet, ferroelectric and antiferromagnetic behaviors of ZnO doped with various exotic elements (exotic doping) have been reported. This paper discusses the OIC application of ZnO thin films doped with exotic elements.

A New Dislocation-Dynamics Model and Its Application in Thin Film-Substrate Systems

2005 ◽  
Vol 875 ◽  
Author(s):  
E.H. Tan ◽  
L.Z. Sun
Keyword(s):  
Thin Films ◽  
Mechanical Performance ◽  
Dislocation Motion ◽  
Dislocation Dynamics ◽  
Dislocation Segment ◽  
Dislocation Loops ◽  
Dynamics Model ◽  
Proposed Model ◽  
Simulation Results ◽  
Film Substrate

AbstractBased on the physical background, a new dislocation dynamics model fully incorporating the interaction among differential dislocation segments is developed to simulate 3D dislocation motion in crystals. As the numerical simulation results demonstrate, this new model completely solves the long-standing problem that simulation results are heavily dependent on dislocation-segment lengths in the classical dislocation dynamics theory. The proposed model is applied to simulate the effect of dislocations on the mechanical performance of thin films. The interactions among the dislocation loops, free surface and interfaces are rigorously computed by a decomposition method. This framework can be used to simulate how a surface loop evolves into two threading dislocations and to determine the critical thickness of thin films. Furthermore, the relationship between the film thickness and yield strength is established and compared with the conventional Hall-Petch relation.

Influence of Initial Defects on the Mechanical Properties of Single Crystal Copper: Discrete Dislocation Dynamics Study

2018 ◽  
Vol 913 ◽  
pp. 627-635
Author(s):  
Ming Yi Zhang ◽  
Min Zhong ◽  
Shuai Yuan ◽  
Jing Song Bai ◽  
Ping Li
Keyword(s):  
Dislocation Density ◽  
Single Crystal ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Dislocation Dynamics ◽  
Single Crystal Copper ◽  
Discrete Dislocation Dynamics ◽  
Discrete Dislocation ◽  
Stress Curve ◽  
Initial Dislocation Density

In this paper, three dimensional discrete dislocation dynamics method was used to quantitatively investigate the influence of initial defects on mechanical response of single crystal copper. Both the irradiation defects (interstitial loops) and random dislocation lines with different densities are considered. The simulation results demonstrate that the yield strength of single crystal copper is higher with higher initial dislocation density and higher interstitial loop density. Dislocation density increases quickly by nucleation and multiplication and microbands are formed during plastic deformation when only the random dislocation lines are initially considered. Characteristics of microbands show excellent agreement with experiment results. Dislocation multiplication is suppressed in the presence of interstitial loops, and junctions and locks between dislocations and interstitial loops are formed. Dislocation density evolution shows fluctuation accompanied with strain-stress curve fluctuation.

Discrete dislocation sim ulation of thin film plasticit y

2001 ◽  
Vol 673 ◽  
Author(s):  
B. von Blanckenhagen ◽  
P. Gumbsch ◽  
E. Arzt
Keyword(s):  
Thin Film ◽  
Dislocation Motion ◽  
Source Size ◽  
Dislocation Dynamics ◽  
Polycrystalline Thin Film ◽  
Confined Geometry ◽  
Free Standing ◽  
Capping Layer ◽  
Discrete Dislocation Dynamics ◽  
Discrete Dislocation

ABSTRACTA discrete dislocation dynamics sim ulation is used to investigate dislocation motion in the confined geometry of a polycrystalline thin film. The repeated activ ation of a Frank-Read source is sim ulated. The stress to activate the sources and to initiate plastic fiow is significantly higher than predicted by models where the dislocations extend o ver the entire film thic kness. An efiective source size, which scales with the grain dimensions, yields fiow stresses in reasonable agreemen t with experimen ts. The infiuence of dislocations deposited at interfaces is investigated by comparing calculations for a film sandwic hed between a substrate and a capping layer with those for a free standing film.

scholarly journals Influence of Size on the Fractal Dimension of Dislocation Microstructure

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 478
Author(s):  
Yinan Cui ◽  
Nasr Ghoniem
Keyword(s):  
Fractal Dimension ◽  
Three Dimensional ◽  
Dislocation Dynamics ◽  
Two Dimensional ◽  
Discrete Dislocation Dynamics ◽  
Discrete Dislocation ◽  
Transmission Electron ◽  
Dynamics Simulations ◽  
2D And 3D ◽  
Microscopy Images

Three-dimensional (3D) discrete dislocation dynamics simulations are used to analyze the size effect on the fractal dimension of two-dimensional (2D) and 3D dislocation microstructure. 2D dislocation structures are analyzed first, and the calculated fractal dimension ( n 2 ) is found to be consistent with experimental results gleaned from transmission electron microscopy images. The value of n 2 is found to be close to unity for sizes smaller than 300 nm, and increases to a saturation value of ≈1.8 for sizes above approximately 10 microns. It is discovered that reducing the sample size leads to a decrease in the fractal dimension because of the decrease in the likelihood of forming strong tangles at small scales. Dislocation ensembles are found to exist in a more isolated way at the nano- and micro-scales. Fractal analysis is carried out on 3D dislocation structures and the 3D fractal dimension ( n 3 ) is determined. The analysis here shows that ( n 3 ) is significantly smaller than ( n 2 + 1 ) of 2D projected dislocations in all considered sizes.

The HREM observation of the boundary between YBCO thin film and substrate

1990 ◽  
Vol 48 (4) ◽  
pp. 96-97
Author(s):  
W. Liu ◽  
Y. G. Wang ◽  
L. Li
Keyword(s):  
Thin Film ◽  
Film Surface ◽  
High Resolution Electron Microscopy ◽  
Ybco Thin Film ◽  
High Critical Current Density ◽  
Cross Sectional ◽  
Face To Face ◽  
Resolution Electron ◽  
Film Substrate ◽  
Substrate Sample

It is a very important problem to obtain high critical current density Jc in high critical temperature Tc superconductors. For high Tc thin film superconductors, the Jc value can reach >106 A/cm2 at 77K. We have prepared YBa2Cu3Oy (YBCO) thin films by magnetron sputtering method, the Jc values ranged from 104 -106 A/cm2, the films were deposited both on (100) SrTiO3 and (100) LaAlO3 substrates. It is well known that Jc is closely related to the microstructure of the film, in this paper we report the observation by high resolution electron microscopy of the boundary between film and substrate and analysis the result with relation to the Jc values of the films.The cross sectional specimens of the film and substrate boundary were prepared by cutting the film-substrate sample into thin slices, then stick the slices with film surface face to face by epoxy resin.

A study of the submicron indent-induced plastic deformation

1999 ◽  
Vol 14 (6) ◽  
pp. 2251-2258 ◽  
Author(s):  
C. F. Robertson ◽  
M. C. Fivel
Keyword(s):  
Plastic Deformation ◽  
Three Dimensional ◽  
Dislocation Nucleation ◽  
Dislocation Dynamics ◽  
Dynamics Simulation ◽  
Nanoindentation Test ◽  
Experimental Conditions ◽  
Discrete Dislocation Dynamics ◽  
Discrete Dislocation ◽  
Transmission Electron

A new method has been developed to achieve a better understanding of submicron indent-induced plastic deformation. This method combines numerical modeling and various experimental data and techniques. Three-dimensional discrete dislocation dynamics simulation and the finite element method (FEM) were used to model the experimental conditions associated with nanoindentation testing in fcc crystals. Transmission electron microscopy (TEM) observations of the indent-induced plastic volume and analysis of the experimental loading curve help in defining a complete set of dislocation nucleation rules, including the shape of the nucleated loops and the corresponding macroscopic loading. A validation of the model is performed through direct comparisons between a simulation and experiments for a nanoindentation test on a [001] copper single crystal up to 50 nm deep.

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