Energy Minimization During Epitaxial Grain Growth: Strain VS. Interfacial Energy

1993 ◽  
Vol 317 ◽  
Author(s):  
J. A. Floro ◽  
R. Carel ◽  
C. V. Thompson
Keyword(s):  
Grain Growth ◽  
Interfacial Energy ◽  
Energy Minimization ◽  
Strain Energy ◽  
Elastic Anisotropy ◽  
Interface Energy ◽  
Growth Strain ◽  
Free Energies ◽  
Film Substrate ◽  
Epitaxial Grain Growth

ABSTRACTWe have investigated Epitaxial Grain Growth (EGG) in polycrystalline Ag films on Ni (001) substrates. EGG is driven by minimization of crystallographically anisotropie free energies such as the film/substrate interfacial energy and the film strain. Under some conditions EGG results in the preferred growth of the (111) epitaxial orientations that are predicted to minimize the interfacial energy. However, when Ag films are deposited on Ni (001) at low temperature, EGG experiments consistently find that (111) oriented grains are consumed by grains with (001) orientations predicted to have much higher interface and surface energy. The large elastic anisotropy of Ag can account for this discrepancy. The film thickness and the deposition temperature (relative to the grain growth temperature) determine whether strain energy or interface energy minimization dominates orientation evolution during grain growth.

Competition between strain and interface energy during epitaxial grain growth in Ag films on Ni(001)

1994 ◽  
Vol 9 (9) ◽  
pp. 2411-2424 ◽  
Author(s):  
J.A. Floro ◽  
C.V. Thompson ◽  
R. Carel ◽  
P.D. Bristowe
Keyword(s):  
Surface Energy ◽  
Grain Growth ◽  
Interfacial Energy ◽  
Elastic Anisotropy ◽  
Interface Energy ◽  
Orientation Dependence ◽  
Embedded Atom ◽  
Strain Energy Minimization ◽  
Film Substrate ◽  
Epitaxial Grain Growth

Epitaxial Grain Growth (EGG) is an orientation-selective process that can occur in polycrystalline thin films on single crystal substrates. EGG is driven by minimization of crystallographically anisotropic free energies. One common driving force for EGG is the reduction of the film/substrate interfacial energy. We have carried out experiments on polycrystalline Ag films on Ni(001) substrates. The orientation dependence of the Ag/Ni interfacial energy has been previously calculated using the embedded atom method. Under some conditions, EGG experiments lead to the (111) orientations calculated to be interface- and surface-energy-minimizing. However, when Ag films are deposited on Ni(001) at low temperature, EGG experiments consistently find that (111) oriented grains are consumed by grains with (001) orientations predicted to have much higher interface and surface energy. The large elastic anisotropy of Ag can account for this discrepancy. Strain energy minimization favors growth of (001) grains and can supersede minimization of interfacial energy if sufficient strain is present and if the film is initially unable to relieve the strain by plastic deformation.

The Origins of Epitaxial Orientations in thin Films

1992 ◽  
Vol 280 ◽  
Author(s):  
Carl V. Thompson
Keyword(s):  
Single Crystal ◽  
Grain Growth ◽  
Energy Minimization ◽  
Strain Energy ◽  
Single Crystal Substrate ◽  
Continuous Film ◽  
Orientation Selection ◽  
Strain Energy Minimization ◽  
Film Substrate ◽  
Epitaxial Grain Growth

ABSTRACTWhen a continuous film is deposited on a planar, single crystal substrate, there is usually a single set of relative film-substrate orientations for which the free energy of the film-substrate interface is minimized. It is often assumed that epitaxial films have adopted the orientation which minimizes this energy. However, this is not necessarily the case. Orientation selection is also constrained by minimization of the energy of the/ree surface of a film, as well as by minimization of the strain energy. In systems in which films grow by an island mechanism, epitaxial orientations can be established during or after nucleation, and can change before or after formation of a continuous film. Interfacial and surface energy minimization is constrained differently for islands and films. Epitaxial grain growth is a process which occurs in continuous films, in which epitaxially-aligned, energy-minimizing grains grow at the expense of other grains. Recent experiments on epitaxial grain growth in polycrystalline Ag films on single crystal Ni is discussed to illustrate, the affects of surface, interface, and strain energy minimization on epitaxial orientation selection.

Computer Simulation of Strain Energy and Surface- and Interface-Energy on Grain Growth in Thin Films

1994 ◽  
Vol 343 ◽  
Author(s):  
R. Carel ◽  
C. V. Thompson ◽  
H. J. Frost
Keyword(s):  
Thin Films ◽  
Grain Growth ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Driving Forces ◽  
Interface Energy ◽  
Orientation Dependence ◽  
Surface And Interface ◽  
Elastic Regime ◽  
Strained Films

ABSTRACTWe have simulated strain energy effects and surface- and interface-energy effects on grain growth in thin films, using properties of polycrystalline Ag (p-Ag) on single crystal (001) Ni on (001) MgO for comparison with experiments. Surface- and interface-energy and strain energy reduction drive the growth of grains of specific crystallographic orientations. The texture that will result when grain growth has occurred minimizes the sum of these driving forces. In the elastic regime, strain energy density differences result from the orientation dependence of the elastic constants of the biaxially strained films. In the plastic regime, strain energy also depends on grain diameter and film thickness. In p-Ag/(001) Ni, surface- and interface-energy minimization favors Ag grains with (11) texture. In the absence of a grain growth stagnation, the texture at later times is always (111). However, for high enough strains and large enough thicknesses, the strain energy driving force can favor a (001) texture at early times, which reverts to a (111) texture at later times, once the grains have yielded.

scholarly journals Failure by simultaneous grain growth, strain localization, and interface debonding in metal films on polymer substrates

2009 ◽  
Vol 24 (2) ◽  
pp. 379-385 ◽  
Author(s):  
Nanshu Lu ◽  
Xi Wang ◽  
Zhigang Suo ◽  
Joost Vlassak
Keyword(s):  
Grain Growth ◽  
Strain Localization ◽  
Deformation Process ◽  
Copper Film ◽  
Metal Films ◽  
Thin Metal Film ◽  
Interface Debonding ◽  
Growth Strain ◽  
Polymer Substrates ◽  
Film Substrate

In a previous paper, we have demonstrated that a microcrystalline copper film well bonded to a polymer substrate can be stretched beyond 50% without cracking. The film eventually fails through the coevolution of necking and debonding from the substrate. Here we report much lower strains to failure (approximately 10%) for polymer-supported nanocrystalline metal films, the microstructure of which is revealed to be unstable under mechanical loading. We find that strain localization and deformation-associated grain growth facilitate each other, resulting in an unstable deformation process. Film/substrate delamination can be found wherever strain localization occurs. Therefore, we propose that three concomitant mechanisms are responsible for the failure of a plastically deformable but microstructurally unstable thin metal film: strain localization at large grains, deformation-induced grain growth, and film debonding from the substrate.

Grain Growth in Polycrystalline Thin Films

1994 ◽  
Vol 343 ◽  
Author(s):  
Carl V. Thompson
Keyword(s):  
Thin Films ◽  
Grain Growth ◽  
Energy Minimization ◽  
Film Formation ◽  
Interface Energy ◽  
Surface And Interface ◽  
Grain Sizes ◽  
Thermal Expansion Coefficients ◽  
Average Grain Size ◽  
Strain Energy Minimization

ABSTRACTThe performance and reliability of polycrystalline films are strongly affected by the average grain size and the distribution of grain sizes and orientations. These are often controlled through grain growth phenomena which occur during film formation and during subsequent processing. Abnormal rather than normal grain growth is most common in thin films, and leads to an evolution in the distribution of grain orientations as well as grain sizes, often leading to uniform or restricted crystallographic orientations or textures. Surface and interface energy minimization and strain energy minimization can lead to development of different textures, depending on which is dominant. The final texture resulting from grain growth depends on the film thickness, the deposition temperature, the grain growth temperature, the thermal expansion coefficients of the film and substrate, and the mechanical properties of the film, as well as other factors.

Studies on the Nucleation Behaviors of Precipitation in Aluminum Metallization

1992 ◽  
Vol 260 ◽  
Author(s):  
Jen-Ren Wang ◽  
Jian-Yang Lin ◽  
Huey-Liang Hwang
Keyword(s):  
Activation Energy ◽  
Electrical Properties ◽  
Interfacial Energy ◽  
Strain Energy ◽  
Weight Percent ◽  
Free Energies ◽  
Interfacial Energies ◽  
Mechanical And Electrical Properties ◽  
Aluminum Metallization ◽  
Aluminum Interconnects

ABSTRACTIn order to simulate the precipitation effect during the aluminum metallization in the VLSI processing, an analytical model was constructed in this work. The nucleation behaviors of the silicon and copper precipitates within the aluminum - 1.0 weight percent silicon - 0.5 weight percent copper were studied. The volume free energies and interfacial energies were estimated, and the activation energy barriers for the precipitate formation were calculated. Silicon precipitate is more likely to nucleate than copper precipitate due to its lower interfacial energy and strain energy. The mechanical and electrical properties of the aluminum interconnects can be improved by the precipitate hardening.

Epitaxial Grain Growth and Orientation Metastability in Heteroepitaxial Thin Films

1990 ◽  
Vol 187 ◽  
Author(s):  
J. A. Floro ◽  
C. V. Thompson
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Free Energy ◽  
Free Surface ◽  
Grain Growth ◽  
Film Growth ◽  
Metal Films ◽  
Thin Film Growth ◽  
Film Substrate ◽  
Epitaxial Grain Growth

AbstractConventional heteroepitaxial thin film growth may result in a film whose epitaxial orientation is metastable. One method of probing the relative energies of various film orientations is epitaxial grain growth. Epitaxial grain growth selects the orientation having lowest total free energy, including the free energy of both the film-substrate interface and the free surface of the film. Experimental examples of epitaxial grain growth in metal films on insulating substrates will be discussed.

Texture Maps for Orientation Evolution During Grain Growth in Thin Films

1995 ◽  
Vol 403 ◽  
Author(s):  
Steven C. Seel ◽  
Roland Carel ◽  
Carl V. Thompson
Keyword(s):  
Thin Films ◽  
Grain Growth ◽  
Strain Energy ◽  
Driving Forces ◽  
Chemical Vapor ◽  
Interface Energy ◽  
Fcc Metals ◽  
Surface And Interface ◽  
Different Temperatures ◽  
Energy Anisotropy

AbstractOrientation selective grain growth in thin films arises due to anisotropy in materials properties. For continuous thin films, there are at least two orientation dependent driving forces for grain growth: (i) surface and interface energy anisotropy; (ii) strain energy anisotropy (both elastic and plastic). In fcc metals, the preferred growth of grains with (111) texture occurs due to their low surface and interface energy. Stresses in thin films arise during deposition and as a result of post-deposition annealing. A texture dependence of strain energy density arises in biaxially strained thin films due to anisotropy of elastic properties and/or orientation-dependent yield stresses. For most fcc metals, the strain energy driving force promotes the growth of (001) grains due to minimization of the combined elastic and plastic strain energy. The magnitudes of the orientation dependent driving forces for grain growth depend on the characteristics and processing conditions of the film and substrate. We have performed grain growth experiments for Ag films on single crystal Ni on MgO; Ag films on plasma-enhanced chemical vapor deposited (PECVD) SiO2 on MgO; Ag films on oxidized Si; and Ni films on oxidized Si. The texture resulting from grain growth in films of different thicknesses and deposited at different temperatures were determined, and the results are presented in the form of texture maps. The texture which dominates as a result of grain growth can be understood through the use of texture maps and compares well with analytic models for texture development during grain growth in thin films.

Effect of Micro-Elasticity on Grain Growth and Texture Evolution: A Phase Field Study

2010 ◽  
Vol 654-656 ◽  
pp. 1590-1593 ◽  
Author(s):  
Dong Uk Kim ◽  
Seong Gyoon Kim ◽  
Won Tae Kim ◽  
Jae Hyung Cho ◽  
Heung Nam Han ◽  
...  
Keyword(s):  
Energy Density ◽  
Grain Growth ◽  
Phase Field ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Elastic Anisotropy ◽  
Texture Evolution ◽  
Fiber Texture ◽  
Abnormal Grain Growth ◽  
Elastic Load

In this presentation, a novel phase field grain growth model combined with a micro-elasticity effect including elastic anisotropy and inhomogeity is presented to demonstrate the effect of micro-elasticity on grain growth and texture evolution. We report on texture evolution and abnormal grain growth induced by external elastic load from the viewpoint of micro-elasticity and first demonstrate that the previous mechanism (macroscopic viewpoint) on the effect of external elastic load on grain growth does not work in strain-controlled system. In contrast to the macro-elastic descriptions, strong localization of strain energy density and inhomogeneous distribution even inside grains are observed. Moreover, elastically soft grains with a higher strain energy density grow at the expense of the elastically hard grains to reduce the total strain energy. It is observed that strong <100>//ND fiber texture was developed in poly-crystalline Cu with initial random texture by biaxial external strain while <111>//ND fiber texture evolved in biaxial external stress condition. Even, grain growth of <100>//ND textured grains is occurred as abnormal grain growth when <100>//ND textured grains are surrounded by <111>//ND fiber textured grains.

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