Residual Stresses for In-Situ Deposition of Thin-Film High-Temperature Superconductors

1994 ◽  
Vol 116 (4) ◽  
pp. 249-257 ◽  
Author(s):  
P. E. Phelan ◽  
M. N. Ghasemi Nejhad
Keyword(s):  
Thin Film ◽  
Residual Stress ◽  
Residual Stresses ◽  
High Temperature Superconductors ◽  
Oxygen Stoichiometry ◽  
Chemical Shrinkage ◽  
In Situ Deposition ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

Residual stresses are caused by nonuniform thermal expansion and chemical shrinkage taking place during processing. For thin-film high-temperature superconductors, residual stresses result because of the thermal expansion mismatch between the film and substrate, and the introduction of oxygen into the film after in-situ deposition, which makes the unit cell dimensions change (chemical shrinkage) as the oxygen stoichiometry changes. Since both the reliability of the film—especially the bond between the film and substrate—and the film critical temperature are functions of the state of stress, it is important to understand how the residual stresses vary with processing conditions. Here, a three-dimensional residual stress analysis is carried out based on laminate theory, which assumes the lateral dimensions of the entire system to be much larger than its thickness. The normal residual stress components in the film, and the peeling stress at the film/substrate interface, are calculated. The results demonstrate the crucial role that chemical shrinkage plays in the formulation of residual stresses. A large portion of the stresses arises from the initial change of the unit cell dimensions due to changes in the film oxygen stoichiometry. Therefore, the processing temperature, and especially the initial oxygen pressure in the deposition chamber, are the key variables that impact the residual stresses.

scholarly journals Why In Situ, Real-Time Characterization of Thin-Film Growth Processes?

MRS Bulletin ◽  
1995 ◽  
Vol 20 (5) ◽  
pp. 14-17 ◽  
Author(s):  
Orlando Auciello ◽  
Alan R. Krauss
Keyword(s):  
Thin Film ◽  
Real Time ◽  
Analytical Methods ◽  
Film Growth ◽  
High Temperature Superconductors ◽  
Thin Layers ◽  
Thin Film Growth ◽  
Sampling Depth ◽  
Growth Environment

It is anticipated that a new generation of advanced electronic and optical devices will involve the synthesis of diverse materials in single or multielement thin-film form, or in layered heterostructures. These devices will most likely involve diverse materials such as high-temperature superconductors, ferroelectric, electrooptic, and optical materials; diamond; nitrides; semiconductors; insulators; and metals in the form of ultra-thin layers with sharp interfaces in which the layer thickness may reach atomic dimensions. Therefore, it becomes increasingly important to be able to monitor the deposition process in situ and in real time, particularly for complex multicomponent oxides or nitrides, in which the production of the desired phase is a highly sensitive function of the growth conditions, often requiring relatively high-pressure oxygen or nitrogen environments up to several hundred mTorr, and in some cases, several Torr. Consequently, the growth environment for many of these materials is incompatible with conventional surface-analytic methods, which are typically restricted to high-or ultrahigh-vacuum conditions. New deposition and analytical methods, or adaptation of those already established, will be required.Since thin-film growth occurs at the surface, the analytical methods should be highly surface-specific, although sub-surface diffusion and chemical processes also affect film properties. Sampling depth and ambient-gas compatibility are key factors which must be considered when choosing in situ probes of thin-film growth phenomena. In most cases, the sampling depth depends on the mean range of the exit species (ion, photon, or electron) in the sample.

RESIDUAL STRESSES IN OBLIQUE INCIDENCE DEPOSITED ALUMINA THIN FILM

2014 ◽  
Vol 21 (02) ◽  
pp. 1450024 ◽  
Author(s):  
LIJUN HE ◽  
CHUAN LI ◽  
XINGZHAO LIU
Keyword(s):  
Thin Film ◽  
Residual Stress ◽  
Residual Stresses ◽  
Film Thickness ◽  
Substrate Temperature ◽  
Deposition Rate ◽  
Growth Parameters ◽  
Testing Temperature ◽  
Alumina Thin Film ◽  
Inclined Angle

Residual stresses of alumina thin film deposited on silicon substrate by using electron beam evaporation with oblique angle deposition (OAD) method are studied. The growth parameters that affect the residual stresses of alumina thin film, such as the substrate temperature, the deposition rate, the film thickness, the inclined angle, and the testing temperature are discussed. The results show that the tensile stress value decreases with the increasing substrate temperature, and the compressive stress value increases with the increasing substrate temperature at various inclined angles. Along with the deposition rate increasing, the residual stress value decreases at various inclined angles. With the increasing film thickness, the residual stress value decreases at various inclined angles. With the increasing testing temperature, the residual stress value increases at various inclined angles. While the alumina thin film residual stress value is small at high inclined angle. By choosing the appropriate film preparation parameters, the alumina thin film residual stress is effectively controlled.

Thin-Film Residual Stress Detection Method Based on Flexible Hinges

2012 ◽  
Vol 548 ◽  
pp. 367-371
Author(s):  
Hai Wang ◽  
Yun Hua Tong
Keyword(s):  
Thin Film ◽  
Residual Stress ◽  
Detection Method ◽  
Stress Detection ◽  
Suspended Structure ◽  
Sacrificial Layers ◽  
Detection Principle

The residual stress introduced in the thin-film process may caused some problems, especially after removing of the sacrificial layers below, the suspended structure may be bended due to the release. In this articles we will develop a new in-situ residual stress detection method based on flexible hinges for thin-film materials, then described the detection principle theoretically and simulated its properties by FEA method.

scholarly journals Thin film stress and microstructure analysis by energy-dispersive diffraction

2014 ◽  
Vol 70 (a1) ◽  
pp. C724-C724
Author(s):  
Christoph Genzel
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Residual Stress ◽  
Film Growth ◽  
High Energy ◽  
Energy Dispersive ◽  
Film Stress ◽  
Ex Situ ◽  
Near Surface

The most important advantage of energy dispersive (ED) diffraction compared with angle dispersive methods is that the former provides complete diffraction patterns in fixed but arbitrarily selectable scattering directions. Furthermore, in experiments that are carried out in reflection geometry, the different photon energies E(hkl) of the diffraction lines in an ED diffraction pattern can be taken as an additional parameter to analyze depth gradients of structural properties in the materials near surface region. For data evaluation advantageous use can be made of whole pattern methods such as the Rietveld method, which allows for line profile analysis to study size and strain broadening [1] or for the refinement of models that describe the residual stress depth distribution [2]. Concerning polycrystalline thin films, the features of ED diffraction mentioned above can be applied to study residual stresses, texture and the microstructure either in ex-situ experiments or in-situ to monitor, for example, the chemical reaction pathway during film growth [3]. The main objective of this talk is to demonstrate that (contrary to a widespread opinion) high energy synchrotron radiation and thin film analysis may fit together. The corresponding experiments were performed on the materials science beamline EDDI at BESSY II which is one of the very few instruments worldwide that is especially dedicated to ED diffraction. On the basis of selected examples it will be shown that specially tailored experimental setups allow for residual stress depth profiling even in thin films and multilayer coatings as well as for fast in situ studies of film stress and microstructure evolution during film growth.

Effect of Initial Residual Stress on Stress Relaxation in Cold-Drawn Steel Rods

2010 ◽  
Vol 652 ◽  
pp. 227-232
Author(s):  
Jesus Ruiz-Hervias ◽  
Jose M. Atienza ◽  
Javier R. Santisteban ◽  
Manuel Elices Calafat
Keyword(s):  
Residual Stress ◽  
Stress Relaxation ◽  
Residual Stresses ◽  
Cross Section ◽  
Stress Relaxation Behavior ◽  
Relaxation Experiment ◽  
Initial Residual Stress ◽  
Residual Stress State ◽  
Residual Strains

This work shows the effect of the initial residual stress state on the stress relaxation behavior of cold-drawn steel rods. The evolution of residual strains at several locations along the rod diameter was measured in-situ by neutron diffraction during a stress relaxation experiment. It was found that if residual stresses are significant, stress relaxation is not homogeneous in the cross-section of the rods. This also explains the higher stress losses found in the rods with high residual stresses.

Finite element modeling of stress variation in multilayer thin-film specimens for in situ transmission electron microscopy experiments

2007 ◽  
Vol 22 (10) ◽  
pp. 2737-2741 ◽  
Author(s):  
H. Mei ◽  
J.H. An ◽  
R. Huang ◽  
P.J. Ferreira
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Finite Element Method ◽  
Transmission Electron Microscopy ◽  
Finite Element ◽  
Residual Stresses ◽  
Multilayer Thin Film ◽  
Stress Variation ◽  
Transmission Electron

Multilayer thin-film materials with various thicknesses, compositions, and deposition methods for each layer typically exhibit residual stresses. In situ transmission electron microscopy (TEM) is a powerful technique that has been used to determine correlations between residual stresses and the microstructure. However, to produce electron transparent specimens for TEM, one or more layers of the film are sacrificed, thus altering the state of stresses. By conducting a stress analysis of multilayer thin-film TEM specimens, using a finite element method, we show that the film stresses can be considerably altered after TEM sample preparation. The stress state depends on the geometry and the interactions among multiple layers.

Residual Stress Analysis of A Multi-Layer Thin Film Structure by Destructive (Curvature) and Non-Destructive (X-Ray) Methods

1989 ◽  
Vol 153 ◽  
Author(s):  
P.C. Chen ◽  
Yoshiki Oshida
Keyword(s):  
Thin Film ◽  
Residual Stress ◽  
Residual Stresses ◽  
Material System ◽  
Ray Method ◽  
X Ray ◽  
Removal Method ◽  
Layer Removal ◽  
Layer Removal Method ◽  
Layer Thin Film

AbstractMulti-layer thin film which has structure of Cu/Cr/K/Cr/Cu prepared by sputtering process was analyzed for interfacial stresses for as-deposited conditions. This structure was also annealed at 150°C, 250°C, and 350°C for around 15 min. in a vacuum and cooled slowly down for stress analyses.Equations derived by Osgood [1] for residual stress estimations for homogeneous material system using layer removal technique (stress relief) is now applied for inhomogeneous system (multilayer structure). The results are compared with the data obtained from x-ray diffraction technique by using sin2Ψ-2θ method, for Cu layer.From the present analyses, the data obatined using layer removal seem to be qualitatively consistent with but not quantitatively in agreement with x-ray method. Data obtained using the layer removal method have some overlaps with those obtained from x-ray technique. However, in details, data from the curvature method present different scattering band from the x-ray method. It is suggested that the layer removal method is more practical to be used to estimate the average residual stress of the multi-layer system not only because the layer removal method estimates the bulk behavior but also when the metal film is thin (e.g., 200A for Cr layer), x-ray technique becomes impractical. By annealing the sputtered structure up to 250°C, the residual stresses, in particularly Cu layer, decreased on both sides in x- and y-directions.From the main results drawn from the present studies, the layer removal sequence for the curvature method shows significant affects on the obtained results of residual stresses. Minimizing influences caused by layer removal sequences as well as removing duration and temperature provides the most accurate results on residual stress measurements.

scholarly journals Experiments with in-situ thin film telephone cord buckling delamination propagation

2002 ◽  
Vol 749 ◽  
Author(s):  
Alex A. Volinsky
Keyword(s):  
Thin Film ◽  
Residual Stress ◽  
Compressive Residual Stress ◽  
In Situ Observation ◽  
Crack Healing ◽  
Buckling Delamination ◽  
Film Substrate ◽  
Delamination Propagation ◽  
Analysis Of Motion

ABSTRACTThere are many different stress relief mechanisms observed in thin films. One of the mechanisms involves film debonding from the substrate. In the case of tensile residual stress a network of through-thickness cracks forms in the film. In the case of compressive residual stress thin film buckling and debonding from the substrate in the form of blisters is observed. The buckling delamination blisters can be either straight, or form periodic buckling patterns commonly known as telephone cord delamination morphology.The mechanics of straight-sided blisters is well understood. Current study relies on the in-situ observation of phone cord delamination propagation in different thin film/substrate systems. Both straight and phone cord delaminations are shown to simultaneously propagate in the same film system. Straight-sided blisters propagate several times faster than the phone cords, and may be followed by thin film fracture along the line of maximum film buckling amplitude. Phone cord delaminations originally start as straight-sided blisters, but then deviate to the periodic phone cord geometry due to the fact that the compressive residual stress in the film is biaxial. Digital analysis of motion recordings shows that partial crack “healing” is present at the curved portions of the phone cords due to the “secondary” buckling pushing thin film back to the substrate. These experimental observations allow for the correct interpretation of the telephone cord delamination morphology.

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