Control of Residual Stresses in As-Grown Polysilicon by Multi-Layer Deposition: The “Multipoly” Process

1999 ◽  
Vol 605 ◽  
Author(s):  
Hie Yang ◽  
H. Kahn ◽  
A.Q. He ◽  
S.M. Phillips ◽  
A.H. Heuer
Keyword(s):  
Residual Stress ◽  
X Ray Diffraction ◽  
Columnar Microstructure ◽  
X Ray ◽  
Stress Gradients ◽  
Compressive Stresses ◽  
Transmission Electron ◽  
Layer Deposition ◽  
Polysilicon Films ◽  
The Individual

AbstractLPCVD polysilicon thin films deposited between ∼550 and ∼600 °C have an equiaxed microstructure (resulting from crystallization of an initially amorphous deposit) and contain ∼200 MPa residual tensile stresses after deposition, whereas polysilicon films deposited above ∼600 °C have a columnar microstructure and contain ∼300 MPa residual compressive stresses after deposition. Both types of films also contain stress gradients.We have grown films containing multiple layers of polysilicon ("MultiPoly") by cycling the growth temperature between 570 and 615 °C. The multilayer films thus formed are comprised of alternating tensile and compressive layers, and by control of the thickness of the individual layers, the overall stress of the polysilicon can display any value between that of the tensile layer and that of the compressive layer. We have focussed on producing films with zero overall residual stress, as measured by wafer curvature, and have characterized the microstructures by transmission electron microscopy (TEM) and X-ray diffraction (XRD).Because of the stress gradients present in both layers, devices made from films with zero overall residual stress may show distortions after release. We have measured the stress gradients in each type of layer and can design films with zero overall stress and zero overall stress gradients. It is also possible to design films with any level of overall (tensile or compressive) stress but with controlled displacements upon release.

Revision and extension of the standard laboratory technique for X-ray diffraction measurement of residual stress gradients

2007 ◽  
Vol 40 (4) ◽  
pp. 675-683 ◽  
Author(s):  
Cristy L. Azanza Ricardo ◽  
Mirco D'Incau ◽  
Paolo Scardi
Keyword(s):  
Residual Stress ◽  
Hole Drilling ◽  
Al Alloy ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Surface Residual Stress ◽  
X Ray ◽  
Stress Gradients ◽  
Layer Removal ◽  
Removal Technique

A new procedure is proposed to determine sub-surface residual stress gradients by laboratory X-ray diffraction measurements at different depths using a chemical layer-removal technique. The standard correction algorithm for stress relaxation due to layer removal is improved by including corrections for X-ray absorption, and by the addition of constraints imposed by the mechanical equilibrium conditions. Besides correcting the data,i.e.providing more reliable through-thickness residual stress trends, the proposed procedure also provides an elastically compatible and plausible estimate of the residual stress inside the component, well beyond the measured region. The application of the model is illustrated for a set of Al-alloy components shot-peened at different Almen intensities. Results are compared with those given by `blind hole drilling', which is an independent and partly destructive method.

Influence of deposition parameters on the residual stresses of WC-Wo sputtered thin films

MRS Advances ◽  
2020 ◽  
Vol 5 (23-24) ◽  
pp. 1215-1223
Author(s):  
R.R. Phiri ◽  
O.P. Oladijo ◽  
E.T. Akinlabi
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Residual Stresses ◽  
Substrate Surface ◽  
Tribological Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compressive Stresses ◽  
Deposition Parameters ◽  
Cobalt Thin Films

AbstractControl and manipulation of residual stresses in thin films is a key for attaining coatings with high mechanical and tribological performance. It is therefore imperative to have reliable residual stress measurements methods to further understand the dynamics involved. The sin2ψ method of X-ray diffraction was used to investigate the residual stresses on the tungsten carbide cobalt thin films deposited on a mild steel surface to understand the how the deposition parameters influence the generation of residual stresses within the substrate surface. X-ray spectra of the surface revealed an amorphous phase of the thin film therefore the stress measured was of the substrate surface and the effects of sputtering parameters on residual stress were analysed. Compressive stresses were identified within all samples studied. The results reveal that as the sputtering parameters are varied, the residual stresses also change. Optimum deposition parameters in terms of residual stresses were suggested.

scholarly journals Influence of Layer Removal Methods in Residual Stress Profiling of a Shot Peened Steel Using X-Ray Diffraction

2014 ◽  
Vol 996 ◽  
pp. 175-180 ◽  
Author(s):  
Rasha Alkaisee ◽  
Ru Lin Peng
Keyword(s):  
Residual Stress ◽  
Chemical Etching ◽  
Stress Measurement ◽  
Diffraction Measurement ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Layer Removal ◽  
Compressive Stresses ◽  
The Difference

For X-Ray Diffraction Measurement of Depth Profiles of Residual Stress, Step-Wise Removal of Materials has to be Done to Expose the Underneath Layers to the X-Rays. this Paper Investigates the Influence of Layer Removal Methods, Including Electro-Polishing in Two Different Electrolytes and Chemical Etching, on the Accuracy of Residual Stress Measurement. Measurements on Two Shot-Peened Steels Revealed Large Discrepancy in Subsurface Distributions of Residual Stress Obtained with the Respective Methods. Especially, the Chemical Etching Yielded much Lower Subsurface Compressive Stresses than the Electro-Polishing Using a so Called AII Electrolyte. the Difference was Explained by the Influence of the Different Layer Removal Methods on the Microscopic Roughness.

X-Ray Diffraction Measurements of Residual Stress Induced by Surface Compressing Methods

2012 ◽  
Vol 729 ◽  
pp. 199-204 ◽  
Author(s):  
Dávid Cseh ◽  
Valéria Mertinger
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Surface Region ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hardened Alloy ◽  
Compressive Stresses ◽  
Machine Parts ◽  
Stress States ◽  
Operational Behaviour

Residual stresses have a fundamental effect on the operational behaviour and lifetime of industrial products. The fatigue resistance of machine parts can be increased by introducing residual compressive stresses into the surface region. For certain machine parts especially in the vehicle industry the residual stress is strongly demanded by the quality control. For this reason, measuring the stress accurately is becoming increasingly important. The Almen test, which only gives a qualitative result, is widely used in the industry. Shot peening and rolling are methods which are suitable for creating elastic residual stresses. This paper examines the technologies used by Rába Futómű Nyrt. to increase the lifetime by means of residual stress. We performed analysis of the residual stress of samples shot peened the same way but under different heat treatment states. We compared the residual stress values of burnished and hardened shaft joints, and the residual stress states of gear made of hardened alloy, comparing the carbonized ones to ones which were shot peened under small intensity.

Thermal Residual Stress Relaxation in Sputtered ZnO Film on (100) Si Substrate Studied In Situ by Synchrotron X-Ray Diffraction

2011 ◽  
Vol 681 ◽  
pp. 127-132
Author(s):  
Christopher Krauss ◽  
Guillaume Geandier ◽  
Florine Conchon ◽  
Pierre Olivier Renault ◽  
Eric Le Bourhis ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Relaxation ◽  
Structural Changes ◽  
Zno Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Compressive Stresses ◽  
Residual Stress Relaxation

Residual stress relaxation in sputtered ZnO films has been studied in-situ by synchrotron x-ray diffraction. The films deposited on (001) Si substrates were thermally treated from 25°C to 700°C. X-ray diffraction 2D patterns were captured continuously during the heating, plateau and cooling ramps. The corrections carried out for compensating the furnace drift are discussed. We first observe an increase of the intrinsic compressive stresses before stress relaxation starts to operate around 370°C. Then, thermal contraction upon cooling dominates so that overall, the large initial compressive film stresses turn to tensile after thermal treatment. The overall behaviour is discussed in terms of structural changes induced by the heat treatment.

Fabrication of SnS2 Flower Like Nanoflake Assemblies Through Thermal Evaporation

2007 ◽  
Vol 7 (12) ◽  
pp. 4540-4545 ◽  
Author(s):  
Subhajit Biswas ◽  
Soumitra Kar ◽  
Tandra Ghoshal ◽  
Subhadra Chaudhuri
Keyword(s):  
Thermal Evaporation ◽  
Growth Direction ◽  
Vapor Concentration ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Raman Spectroscopic ◽  
Transmission Electron ◽  
Scanning Electron Microscopic ◽  
The Individual

Uniform as well as flower like patterns of SnS2 nanoflakes were produced by a thermal evaporation process. Interpenetrating phenomenon was observed between the individual nanoflakes during the course of their lateral growth. The interpenetrating growth and controlled vapor concentration as well as the substrate temperature leads to the formation of flower like assemblies of SnS2 nanoflakes. Morphology and growth mechanism of the nanostructures were studied by scanning electron microscopic observations at different stages of the nanoflake growth. The produced nanoflakes were characterized by X-ray diffraction, scanning and transmission electron microscopy, and Raman spectroscopic measurements. SnS2 nanoflakes were perfectly single crystalline and growth direction of the nanoflakes was along the {101}-lattice plane.

scholarly journals “Intelligent” Pt Catalysts Based on Thin LaCoO3 Films Prepared by Atomic Layer Deposition

Inorganics ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 113 ◽  
Author(s):  
Xinyu Mao ◽  
Alexandre C. Foucher ◽  
Eric A. Stach ◽  
Raymond J. Gorte
Keyword(s):  
Atomic Layer Deposition ◽  
Co Adsorption ◽  
Atomic Layer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Highly Active ◽  
Transmission Electron ◽  
Layer Deposition ◽  
Scanning Transmission ◽  
Water Gas

LaCoO3 films were deposited onto MgAl2O4 powders by atomic layer deposition (ALD) and then used as catalyst supports for Pt. X-ray diffraction (XRD) showed that the 0.5 nm films exhibited a perovskite structure after redox cycling at 1073 K, and scanning transmission electron microscopy and elemental mapping via energy-dispersive X-ray spectroscopy (STEM/EDS) data demonstrated that the films covered the substrate uniformly. Catalysts prepared with 3 wt % Pt showed that the Pt remained well dispersed on the perovskite film, even after repeated oxidations and reductions at 1073 K. Despite the high Pt dispersion, CO adsorption at room temperature was negligible. Compared with conventional Pt on MgAl2O4, the reduced forms of the LaCoO3-containing catalyst were highly active for the CO oxidation and water gas shift (WGS) reactions, while the oxidized catalysts showed much lower activities. Surprisingly, the reduced catalysts were much less active than the oxidized catalysts for toluene hydrogen. Catalysts prepared from thin films of Co3O4 or La2O3 exhibited properties more similar to Pt/MgAl2O4. Possible reasons for how LaCoO3 affects properties are discussed.

Si/Ge Strained-Layer Epitaxy: Sil−xGex Alloy Buffer Layers and Ultra-Short Period SimGen Superlattices.

1990 ◽  
Vol 198 ◽  
Author(s):  
M. Ospelt ◽  
J. Henz ◽  
E. MÜller ◽  
H. Von KÄnel
Keyword(s):  
Period Doubling ◽  
Interface Roughness ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
X Ray ◽  
3 Dimensional ◽  
Annealing Temperatures ◽  
Transmission Electron ◽  
Short Period ◽  
The Individual

ABSTRACTSil−xGex alloy layers and ultra-short period SimGen superlattices on alloy buffer layers of the same concentration have been grown by MBE. The superlattices as a whole have been shown to have the lattice constant of the underlying alloy buffer layer, the individual Si and Ge layers being fully strained. Samples with a graded Ge content have been used to study the relaxation as a function of Ge content by means of X-ray diffraction and RBS and channeling.Transmission electron spectroscopy reveals that interface roughness is not simply statistical in these superlattices. Rather, electron diffraction shows additional features from a period doubling in the (111) directions, indicating that a corresponding interfacial ordering occurs. These features show 2- or 3-dimensional behavior depending on the thickness of the Si and Ge layers in the superlattices. Annealing studies show these features to persist even for annealing temperatures where the superlattices disintegrate into alloys.

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