Phase Transformation and Microstructural Properties in Sputtered Vs. CVD WSi, Films

1996 ◽  
Vol 441 ◽  
Author(s):  
A. Dornenicucci ◽  
C. Dehm ◽  
S. Loh ◽  
L. A. Clevenger ◽  
C. Dziobkowski ◽  
...  
Keyword(s):  
Grain Size ◽  
Phase Transformation ◽  
Tetragonal Phase ◽  
Hexagonal Phase ◽  
Atomic Ratio ◽  
In Situ Stress ◽  
Ex Situ ◽  
Sputtered Films ◽  
Electron Spectrometry

AbstractCVD WSi, films produced by dichlorosilane reduction at 570°C and WSi, films sputter deposited at 50°C were characterized by in situ x-ray diffraction (IS-XRD), in situ resistivity (ISRes), in situ stress (IS-stress), ex situ/in situ transmission electron microscopy (EX/IS-TEM) and ex situ Auger electron spectrometry (EX-AES) over the temperature range 25–1100°C. The CVD films were crystalline after deposition, with columnar grains in the hexagonal phase and a Si:W atomic ratio of 2.6:1. The CVD films exhibited a sharp hexagonal to tetragonal phase transformation near 750°C. The final grain size was greater than the film thickness, with no evidence of voiding. Avrami analyses gave traditional curves with n values of 2 for the phase transition in the CVD films. In comparison, the sputtered films were amorphous as deposited (Si:W atomic ratio of 2.8:1 ) and crystallized to a different hexagonal phase microstructure than did the CVD films. The sputtered films showed a broad hexagonal to tetragonal phase transformation near 800°C, and a final grain size that was less than the fihn thickness with much voiding. A low Avrami exponent of 0.2 to 0.4 was obtained for the transformation of the sputtered films.

In-Situ Laser Ultrasound Measurements of Austenitic Grain Growth in Plain Carbon Steel

2021 ◽  
Author(s):  
Christian Kerschbaummayr ◽  
Martin Ryzy ◽  
Bernhard Reitinger ◽  
Mike Hettich ◽  
Jan Džugan ◽  
...  
Keyword(s):  
Grain Size ◽  
Carbon Steel ◽  
Grain Growth ◽  
Plain Carbon Steel ◽  
Ex Situ ◽  
Ultrasound Measurement ◽  
Laser Ultrasound ◽  
Austenite Grain Size ◽  
Ultrasound Measurements

Abstract The macroscopic mechanical properties like yield-strength, ductility or hardness play an important role during the steel production and the design of new steel grades. The austenite grain size is an important parameter, which influences the final microstructure and the properties of a material. When developing grain growth evolution models, typically many samples have to be treated thermally and micrographs have to be prepared ex-situ. To reduce the time expenditure of this procedure we carried out in-situ laser ultrasound measurements of austenitic grain growth in plain carbon steel (AISI 1045). A thermomechanical simulator of the type Linseis L78/RITA has been upgraded with a laser ultrasound measurement system, which enables the continuous and contactless determination of the austenite mean grain size during a thermal cycle. In this work we will show the calibration workflow and grain size results by a new attenuation model for plain carbon steel. In-situ laser ultrasound measurement data is compared with several micrographs defined at supporting points along a specified temperature program to corroborate the findings.

A study of ruthenium ultrathin film nucleation on pretreated SiO2 and Hf–silicate dielectric surfaces

2007 ◽  
Vol 22 (8) ◽  
pp. 2254-2264 ◽  
Author(s):  
Filippos Papadatos ◽  
Steven Consiglio ◽  
Spyridon Skordas ◽  
Eric T. Eisenbraun ◽  
Alain E. Kaloyeros
Keyword(s):  
Grain Size ◽  
Rutherford Backscattering Spectrometry ◽  
Substrate Surface ◽  
Compressive Strain ◽  
Chemical Vapor ◽  
Nucleation And Growth ◽  
Ex Situ ◽  
Organic Chemical ◽  
Nucleation Density

This study explored the effects of substrate surface pretreatments on the nucleation and growth of metal–organic chemical vapor deposited ruthenium. In situ plasma (dry), featuring O2, Ar, and H2/Ar chemistries, and ex situ (wet) treatments, consisting of a standard RCA bath, were examined in the nucleation and growth of up to 50-nm-thick metallic Ru films on SiO2 and Hf–silicate surfaces. The resulting surface morphology, grain size, and roughness of the metallic films were examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM), while Rutherford backscattering spectrometry (RBS) was used for compositional measurements. It was determined that an in situ plasma treatment using a H2/Ar yielded metallic Ru films with the highest nucleation density, smallest grain size, and lowest resistivity. Film buckling was also observed for the Ru films deposited on H2/Ar pretreated surfaces. The behavior was attributed to the presence of compressive strain. The films deposited on RCA-cleaned and Ar plasma treated surfaces exhibited very similar physical and electrical characteristics to the films grown on untreated substrates. Alternatively, the use of O2 plasma surface treatment adversely affected Ru nucleation on the SiO2 surface. Relevant mechanisms for Ru nucleation and growth on SiO2 and Hf–silicate nontreated surfaces are discussed in the context of the various predeposition dry and wet treatments.

scholarly journals New Structural Insight into Interface-Controlled α–σ Phase Transformation in Fe-Cr Alloys

2018 ◽  
Vol 2 (4) ◽  
pp. 27
Author(s):  
Wael Al Khoury ◽  
Nobumichi Tamura ◽  
Guillaume Geandier ◽  
Philippe Goudeau
Keyword(s):  
Phase Transformation ◽  
Tetragonal Phase ◽  
Early Stage ◽  
Phase Interface ◽  
The Body ◽  
Ex Situ ◽  
Body Centered Cubic ◽  
Σ Phase ◽  
Two Phases ◽  
Insight Into

Synchrotron Laue microdiffraction scanning is used for the ex situ study of the body-centered, cubic-to-tetragonal phase transformation that occurs in equiatomic polycrystalline Fe-Cr alloys at temperatures between 550 and 800 °C. Grain orientation and grain strains were scanned with a micron step resolution after annealing at 700 °C for 12 h. Further microstructural details on the early stage of the transformation, and more particularly on the cubic-to-tetragonal phase interface, were achieved. Only the α and ordered σ phases were detected. The crystallographic relationships at the interface between the two phases did not follow the predicted rules; this result is discussed in relation to the measured microstrains.

scholarly journals Phase transition of nanoparticulate LiFePO4during high rate cycling

2014 ◽  
Vol 70 (a1) ◽  
pp. C357-C357
Author(s):  
Hao Liu ◽  
Fiona Strobridge ◽  
Olaf Borkiewicz ◽  
Kamila Wiaderek ◽  
Karena Chapman ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Transformation Process ◽  
High Rate ◽  
Ex Situ ◽  
Transformation Mechanism ◽  
Time Resolved ◽  
Diffraction Patterns ◽  
Refinement Strategy ◽  
Non Equilibrium

A fundamental understanding of an electrode material requires the elucidation of its phase transformation mechanism during charge and discharge. Ex situ methods, which are carried out under equilibrium condition, have been widely used in charactering the thermodynamic phases at different states of charge, from which a thermodynamic phase transformation pathway can be constructed. However, ex situ measurements do not always reflect the process occurred in an operating battery as the non-equilibrium operating condition might result in deviations from the thermodynamic process, especially for high-rate materials, such as LiFePO4, which is predicted to exhibit a fundamentally different phase transformation process at high rates [1,2]. To probe the process at high rate, an in situ method with reasonable temporal resolution must be employed. In this work, the high rate galvanostatic cycling process of LiFePO4 nanoparticle electrode in a customised AMPIX cell [3] was investigated in situ by time-resolved synchrotron X-ray powder diffraction. Formation of continuous non-equilibrium solid solution phases between LiFePO4 and FePO4 was observed at 10 C rate. The in situ diffraction patterns were analysed by a refinement strategy that accounts for the asymmetrical diffraction peak profiles due to Li composition variations.

In-Situ Stress Measurements During Dry Oxidation of Silicon

1997 ◽  
Vol 473 ◽  
Author(s):  
Chia-Liang Yu ◽  
Paul A. Flinn ◽  
John C. Bravman
Keyword(s):  
Oxide Thickness ◽  
In Situ Stress ◽  
Stress Generation ◽  
Ex Situ ◽  
Strong Function ◽  
One Dimensional ◽  
Dry Oxidation ◽  
In Situ Stress Measurements ◽  
Good Agreement

ABSTRACTIn this study, we present results of both in-situ and ex-situ measurements of stress generated during dry oxidation of silicon. We show that the mechanical stress in as-grown dry oxides is a strong function of oxidation temperature and oxide thickness, but a weak function of oxygen partial pressure. We have identified a structural relaxation phenomenon after the oxide is formed, and found that the viscosity of the oxide increases with its age; consequently, the stress relaxation slows down due to this increase of viscosity. In this paper, we present a one-dimensional mechanical model to simulate the stress generation and relaxation during dry oxidation of silicon. The simulations of both in-situ and ex-situ tests are in good agreement with the experimental measurements.

Analysis of Phase Transformation Kinetics by Intrinsic Stress Evolutions During the Isothermal Aging of Amorphous Ni(P) and Sn/Ni(P) Films

2004 ◽  
Vol 19 (4) ◽  
pp. 1257-1264 ◽  
Author(s):  
J.Y. Song ◽  
Jin Yu ◽  
T.Y. Lee
Keyword(s):  
Phase Transformation ◽  
Intermetallic Compounds ◽  
Isothermal Aging ◽  
Early Stage ◽  
Interface Reaction ◽  
Aging Treatment ◽  
In Situ Stress ◽  
Intrinsic Stress ◽  
Stress Changes

The kinetics for the crystallization of amorphous Ni(P) films and the formation of intermetallic compounds in Sn/Ni(P) films during isothermal aging treatment were studied with in situ intrinsic stress measurements. The intrinsic stress changes from crystallization were about 200 and 150 MPa for Ni(14P) and Ni(11.7P) films, respectively, and according to Johnson–Mehl–Avrami analysis, the Avrami exponents were about 3.6 ± 0.46 and 4.2 ± 0.39, and the activation energies were 242 and240 kJ/mol, respectively, for the crystallization of Ni(14P) and Ni(11.7P) films. The stress due to the formation of intermetallic compounds such as Ni3Sn4 and Ni3P in Sn/Ni(11.7P) films was about 320 MPa. Application of in situ stress measurementsto the empirical growth model during isothermal phase transformation of Sn/Ni(P) showed that the intermetallic compounds growth was interface reaction-controlled (n = 0.91 ± 0.08) in the early stage and then became diffusion-controlled (n =0.38 ± 0.01), and the activation energy was about 35.9 kJ/mol.

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