scholarly journals In-situ TEM studies on stick-slip friction characters of sp2 nanocrystallited carbon films

Friction ◽  
2022 ◽  
Author(s):  
Xue Fan ◽  
Zelong Hu ◽  
Wenchao Huang
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Interfacial Adhesion ◽  
Carbon Films ◽  
Ex Situ ◽  
In Situ Tem ◽  
Stick Slip ◽  
Slip Step ◽  
Transmission Electron

AbstractCarbon films with two different kinds of sp2 nanocrystallited structure were investigated to study the stick-slip friction with the in-situ and ex-situ tests. In-situ transmission electron microscope (TEM) observation and nanofriction tests revealed that the origins of stick and slip varied with shear stress and film deformation. At the stick stage, shear stress gradually increased with the contact strengthened until reached the shear strength to break the interfacial adhesion; at the slip stage, the shear stress decreased and accompanied with film deformation. During the sliding process, adhesive deformation resulted in the large stick-slip step while ploughing deformation led to a smoother step. Ex-situ nanofriction tests on a series of sp2 nanocrystallited carbon films with different irradiation energies showed the expected sliding behavior with the in-situ results. This study first clarified the mechanism of stick-slip friction with the in-situ TEM observation, which plays the important role for the micro and nano application of sp2 nanocrystallited carbon films.

In-Situ Transmission Electron Microscopy of the Solid-Phase Epitaxial Growth of GaAs: Sample Preparation and Artifact Characterization

1997 ◽  
Vol 480 ◽  
Author(s):  
K. B. Belay ◽  
M. C. Ridgway ◽  
D. J. Llewellyn
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Epitaxial Growth ◽  
Solid Phase ◽  
Ion Beam ◽  
Ex Situ ◽  
In Situ Tem ◽  
Transmission Electron

AbstractIn-situ transmission electron microscopy (TEM) has been used to characterize the solidphase epitaxial growth of amorphized GaAs at a temperature of 260°C. To maximize heat transfer from the heated holder to the sample and minimize electron-irradiation induced artifacts, non-conventional methodologies were utilized for the preparation of cross-sectional samples. GaAs (3xI) mm rectangular slabs were cut then glued face-to-face to a size of (6x3) mm stack by maintaining the TEM region at the center. This stack was subsequently polished to a thickness of ~ 200 ýtm. A 3 mm disc was then cut from it using a Gatan ultrasonic cutter. The disc was polished and dimpled on both sides to a thickness of ~15 mimT.h is was ion-beam milled at liquid nitrogen temperature to an electron-transparent layer. From a comparison of in-situ and ex-situ measurements of the recrystallization rate, the actual sample temperature during in-situ characterization was estimated to deviate by ≤ 20°C from that of the heated holder. The influence of electron-irradiated was found to be negligible by comparing the recrystallization rate and microstructure of irradiated and unirradiated regions of comparable thickness. Similarly, the influence of “thin-foil effect” was found to be negligible by comparing the recrystallization rate and microstructure of thick and thin regions, the former determined after the removal of the sample from the microscope and further ion-beam milling of tens of microns of material. In conclusion, the potential influence of artifacts during in-situ TEM can be eliminated by the appropriate choice of sample preparation procedures.

In Situ TEM Heating Study of the γ Lamellae Formation inside the α2 Matrix of a Ti-45Al-7.5Nb Alloy

2010 ◽  
Vol 146-147 ◽  
pp. 1365-1368 ◽  
Author(s):  
Li Mei Cha ◽  
Helmut Clemens ◽  
Gerhard Dehm ◽  
Zao Li Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ex Situ ◽  
In Situ Tem ◽  
Transmission Electron ◽  
Initial Stage ◽  
Heat Treated ◽  
The Matrix ◽  
In Situ Heating

In-situ heating transmission electron microscopy (TEM) was employed to investigate the initial stage of lamellae formation in a high Nb containing γ-TiAl based alloy. A Ti-45Al-7.5Nb alloy (at %), which was heat treated and quenched in a non-equilibrium state such that the matrix consists of ordered a2 grains, was annealed inside a TEM up to 750 °C. The in-situ TEM study reveals that g laths precipitate in the a2 matrix at ~ 750 °C possessing the classical Blackburn orientation relationship, i.e. (0001)a2 // (111)g and [11-20]a2 // <110]g. The microstructure of the in-situ TEM experiment is compared to results from ex-situ heating and subsequent TEM studies.

scholarly journals Direct imaging of short-range order and its impact on deformation in Ti-6Al

2019 ◽  
Vol 5 (12) ◽  
pp. eaax2799 ◽  
Author(s):  
Ruopeng Zhang ◽  
Shiteng Zhao ◽  
Colin Ophus ◽  
Yu Deng ◽  
Shraddha J. Vachhani ◽  
...  
Keyword(s):  
Direct Observation ◽  
Short Range ◽  
Short Range Order ◽  
Range Order ◽  
Ex Situ ◽  
In Situ Tem ◽  
Dislocation Plasticity ◽  
Transmission Electron ◽  
The Impact

Chemical short-range order (SRO) within a nominally single-phase solid solution is known to affect the mechanical properties of alloys. While SRO has been indirectly related to deformation, direct observation of the SRO domain structure, and its effects on deformation mechanisms at the nanoscale, has remained elusive. Here, we report the direct observation of SRO in relation to deformation using energy-filtered imaging in a transmission electron microscope (TEM). The diffraction contrast is enhanced by reducing the inelastically scattered electrons, revealing subnanometer SRO-enhanced domains. The destruction of these domains by dislocation planar slip is observed after ex situ and in situ TEM mechanical testing. These results confirm the impact of SRO in Ti-Al alloys on the scale of angstroms. The direct confirmation of SRO in relationship to dislocation plasticity in metals can provide insight into how the mechanical behavior of concentrated solid solutions by the material’s thermal history.

In situ TEM measurements of the electrical properties of interface dislocations

1992 ◽  
Vol 50 (2) ◽  
pp. 1338-1339
Author(s):  
F. M. Ross ◽  
R. Hull ◽  
D. Bahnck ◽  
J. C. Bean ◽  
L. J. Peticolas ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Electronic Device ◽  
In Situ Tem ◽  
Device Performance ◽  
Misfit Dislocations ◽  
Electrical Characteristics ◽  
Strained Layer ◽  
Transmission Electron ◽  
Interfacial Dislocations

We describe an investigation of the electrical properties of interfacial dislocations in strained layer heterostructures. We have been measuring both the structural and electrical characteristics of strained layer p-n junction diodes simultaneously in a transmission electron microscope, enabling us to correlate changes in the electrical characteristics of a device with the formation of dislocations.The presence of dislocations within an electronic device is known to degrade the device performance. This degradation is of increasing significance in the design and processing of novel strained layer devices which may require layer thicknesses above the critical thickness (hc), where it is energetically favourable for the layers to relax by the formation of misfit dislocations at the strained interfaces. In order to quantify how device performance is affected when relaxation occurs we have therefore been investigating the electrical properties of dislocations at the p-n junction in Si/GeSi diodes.

In situ TEM Studies of agglomeration of sub-nanometer Ru layers in Ru/C multilayers

1992 ◽  
Vol 50 (1) ◽  
pp. 256-257
Author(s):  
Tai D. Nguyen ◽  
Ronald Gronsky ◽  
Jeffrey B. Kortright
Keyword(s):  
Layered Structure ◽  
Driving Force ◽  
High Energy ◽  
Superior Performance ◽  
In Situ Tem ◽  
Rayleigh Instability ◽  
Practical Applications ◽  
Transmission Electron ◽  
Diffraction Patterns

Nanometer period Ru/C multilayers are one of the prime candidates for normal incident reflecting mirrors at wavelengths < 10 nm. Superior performance, which requires uniform layers and smooth interfaces, and high stability of the layered structure under thermal loadings are some of the demands in practical applications. Previous studies however show that the Ru layers in the 2 nm period Ru/C multilayer agglomerate upon moderate annealing, and the layered structure is no longer retained. This agglomeration and crystallization of the Ru layers upon annealing to form almost spherical crystallites is a result of the reduction of surface or interfacial energy from die amorphous high energy non-equilibrium state of the as-prepared sample dirough diffusive arrangements of the atoms. Proposed models for mechanism of thin film agglomeration include one analogous to Rayleigh instability, and grain boundary grooving in polycrystalline films. These models however are not necessarily appropriate to explain for the agglomeration in the sub-nanometer amorphous Ru layers in Ru/C multilayers. The Ru-C phase diagram shows a wide miscible gap, which indicates the preference of phase separation between these two materials and provides an additional driving force for agglomeration. In this paper, we study the evolution of the microstructures and layered structure via in-situ Transmission Electron Microscopy (TEM), and attempt to determine the order of occurence of agglomeration and crystallization in the Ru layers by observing the diffraction patterns.

In situ TEM observations of melting in nanosized eutectic Pb-Cd inclusions embedded in Al

1996 ◽  
Vol 54 ◽  
pp. 986-987
Author(s):  
S. Hagège ◽  
U. Dahmen ◽  
E. Johnson ◽  
A. Johansen ◽  
V.S. Tuboltsev
Keyword(s):  
Electron Microscope ◽  
Melt Spinning ◽  
Ternary Alloys ◽  
Solid Matrix ◽  
Eutectic System ◽  
In Situ Tem ◽  
In Situ Observation ◽  
Orientation Relationships ◽  
Transmission Electron

Small particles of a low-melting phase embedded in a solid matrix with a higher melting point offer the possibility of studying the mechanisms of melting and solidification directly by in-situ observation in a transmission electron microscope. Previous studies of Pb, Cd and other low-melting inclusions embedded in an Al matrix have shown well-defined orientation relationships, strongly faceted shapes, and an unusual size-dependent superheating before melting.[e.g. 1,2].In the present study we have examined the shapes and thermal behavior of eutectic Pb-Cd inclusions in Al. Pb and Cd form a simple eutectic system with each other, but both elements are insoluble in solid Al. Ternary alloys of Al (Pb,Cd) were prepared from high purity elements by melt spinning or by sequential ion implantation of the two alloying additions to achieve a total alloying addition of up to lat%. TEM observations were made using a heating stage in a 200kV electron microscope equipped with a video system for recording dynamic behavior.

Transmission Electron Microscopy of Epitaxial silicides grown by ultra high vacuum deposition

1989 ◽  
Vol 47 ◽  
pp. 462-463
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
High Vacuum ◽  
High Energy ◽  
Energy Electron ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Transmission Electron

The silicides CoSi2 and NiSi2 are both metallic with the fee flourite structure and lattice constants which are close to silicon (1.2% and 0.6% smaller at room temperature respectively) Consequently epitaxial cobalt and nickel disilicide can be grown on silicon. If these layers are formed by ultra high vacuum (UHV) deposition (also known as molecular beam epitaxy or MBE) their thickness can be controlled to within a few monolayers. Such ultrathin metal/silicon systems have many potential applications: for example electronic devices based on ballistic transport. They also provide a model system to study the properties of heterointerfaces. In this work we will discuss results obtained using in situ and ex situ transmission electron microscopy (TEM).In situ TEM is suited to the study of MBE growth for several reasons. It offers high spatial resolution and the ability to penetrate many monolayers of material. This is in contrast to the techniques which are usually employed for in situ measurements in MBE, for example low energy electron diffraction (LEED) and reflection high energy electron diffraction (RHEED), which are both sensitive to only a few monolayers at the surface.

Growth kinetics of Al2Cu in an Al-1.5Cu thin film by in Situ TEM

1993 ◽  
Vol 51 ◽  
pp. 1172-1173
Author(s):  
M. Park ◽  
S.J. Krause ◽  
S.R. Wilson
Keyword(s):  
Thin Film ◽  
In Situ Tem ◽  
Collector Plate ◽  
Transmission Electron ◽  
Device Processing ◽  
Corrosion Susceptibility ◽  
Precipitation Phenomena ◽  
Semiconductor Chips ◽  
Kinetics Of

Cu alloying in Al interconnection lines on semiconductor chips improves their resistance to electromigration and hillock growth. Excess Cu in Al can result in the formation of Cu-rich Al2Cu (θ) precipitates. These precipitates can significantly increase corrosion susceptibility due to the galvanic action between the θ-phase and the adjacent Cu-depleted matrix. The size and distribution of the θ-phase are also closely related to the film susceptibility to electromigration voiding. Thus, an important issue is the precipitation phenomena which occur during thermal device processing steps. In bulk alloys, it was found that the θ precipitates can grow via the grain boundary “collector plate mechanism” at rates far greater than allowed by volume diffusion. In a thin film, however, one might expect that the growth rate of a θ precipitate might be altered by interfacial diffusion. In this work, we report on the growth (lengthening) kinetics of the θ-phase in Al-Cu thin films as examined by in-situ isothermal aging in transmission electron microscopy (TEM).

A New Method of Wafer Level Plan View TEM Sample Preparation by DualBeam

2008 ◽  
Author(s):  
Hyoung H. Kang ◽  
Michael A. Gribelyuk ◽  
Oliver D. Patterson ◽  
Steven B. Herschbein ◽  
Corey Senowitz
Keyword(s):  
Sample Preparation ◽  
Ex Situ ◽  
Wafer Level ◽  
Cross Sectional ◽  
Plan View ◽  
Manufacturing Line ◽  
Transmission Electron ◽  
Thin Lamella ◽  
Preparation Techniques

Abstract Cross-sectional style transmission electron microscopy (TEM) sample preparation techniques by DualBeam (SEM/FIB) systems are widely used in both laboratory and manufacturing lines with either in-situ or ex-situ lift out methods. By contrast, however, the plan view TEM sample has only been prepared in the laboratory environment, and only after breaking the wafer. This paper introduces a novel methodology for in-line, plan view TEM sample preparation at the 300mm wafer level that does not require breaking the wafer. It also presents the benefit of the technique on electrically short defects. The methodology of thin lamella TEM sample preparation for plan view work in two different tool configurations is also presented. The detailed procedure of thin lamella sample preparation is also described. In-line, full wafer plan view (S)TEM provides a quick turn around solution for defect analysis in the manufacturing line.

scholarly journals In-Situ TEM Annealing Observation of Helium Bubble Evolution in Pre-Irradiated FeCoNiCrTi0.2 Alloys

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3727
Author(s):  
Huanhuan He ◽  
Zhiwei Lin ◽  
Shengming Jiang ◽  
Xiaotian Hu ◽  
Jian Zhang ◽  
...  
Keyword(s):  
Vacuum Arc ◽  
In Situ Tem ◽  
Face Centered Cubic ◽  
Helium Bubble ◽  
High Entropy ◽  
Helium Bubbles ◽  
Transmission Electron ◽  
Bubble Evolution ◽  
Face Centered

The FeCoNiCrTi0.2 high-entropy alloys fabricated by vacuum arc melting method, and the annealed pristine material, are face centered cubic structures with coherent γ’ precipitation. Samples were irradiated with 50 keV He+ ions to a fluence of 2 × 1016 ions/cm2 at 723 K, and an in situ annealing experiment was carried out to monitor the evolution of helium bubbles during heating to 823 and 923 K. The pristine structure of FeCoNiCrTi0.2 samples and the evolution of helium bubbles during in situ annealing were both characterized by transmission electron microscopy. The annealing temperature and annealing time affect the process of helium bubbles evolution and formation. Meanwhile, the grain boundaries act as sinks to accumulate helium bubbles. However, the precipitation phase seems have few effects on the helium bubble evolution, which may be due to the coherent interface and same structure of γ’ precipitation and matrix.

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