Nano Indentations Studies of WC/C and TiN/(Ti,Al)N Multilayer PVD Coatings Combined with Cross-sectional Electron Microscopy Observations

2001 ◽  
Vol 697 ◽  
Author(s):  
N.J.M. Carvalho ◽  
J.Th.M. De Hosson
Keyword(s):  
Electron Microscopy ◽  
Physical Vapor Deposition ◽  
Amorphous Structure ◽  
Fracture Mechanisms ◽  
Accurate Information ◽  
Cross Sectional ◽  
Cracking Mechanisms ◽  
Load Displacement ◽  
A New Technique ◽  
Titanium Aluminum Nitride

AbstractMultilayers of tungsten carbide/carbon (WC/C) with an amorphous structure and multilayers of titanium nitride/titanium-aluminum nitride (TiN/(Ti,Al)N) with a polycrystalline structure, prepared by physical vapor deposition, have been subjected to nanoindentation testing. The investigation has been aimed at establishing whether the load-displacement responses provides accurate information on the fracture mechanisms and whether such mechanisms can be characterized using a new technique for cross-sectional electron microscopy of the nanoindentations. Analysis of the load-displacement curves showed that they can be used to identify the cracking mechanisms occurring in the multilayers and that cross-sectioning of the nanoindentations is necessary if a more complete understanding of the multilayer coatings behavior is required.

Characterization of mechanical properties of tungsten carbide/carbon multilayers: Cross-sectional electron microscopy and nanoindentation observations

2001 ◽  
Vol 16 (8) ◽  
pp. 2213-2222 ◽  
Author(s):  
N. J. M. Carvalho ◽  
J. Th. M. De Hosson
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Tungsten Carbide ◽  
Physical Vapor Deposition ◽  
Hysteresis Loops ◽  
Displacement Curve ◽  
Depth Sensing ◽  
Cross Sectional ◽  
Load Displacement ◽  
A New Technique

Multilayers of tungsten carbide/carbon (WC/C) deposited by physical vapor deposition onto steel substrates were subjected to depth-sensing indentation testing. The investigation aimed at probing the influence of dissimilarities between the microstructure of the multilayers and substrate on the system mechanical properties. The resultant load-displacement data were analyzed both by conventional load-displacement (P-δ) and load-displacement squared (P-δ2) plots. Furthermore, it was demonstrated that the occurrence of annular through-thickness cracks around the indentation sites can be identified from the load-displacement curve. Also, analysis of the lower part of the unloading curve permitted us to identify whether the coating had popped up by localized fracture. The cracking mechanism was characterized using a new technique for cross-sectional electron microscopy of the nanoindentations. The information retrieved with this technique eliminates the problems, inherent in assessing at this small contact scales, whether the fracture is by coating decohesion or by interfacial failure. In our case, it was demonstrated that the failure mechanism was decohesion of the carbon lamellae within the multilayers. The mechanical properties (hardness and effective Young's modulus) were also assessed by nanoindentation. The hysteresis loops were analyzed and discussed in terms of the method developed by Oliver and Pharr [J. Mater. Res. 7, 1564 (1992)].

Fabrication of Planar and Cross-Sectional TEM Specimens Using a Focused Ion Beam

1990 ◽  
Vol 199 ◽  
Author(s):  
R. J. Young ◽  
E. C. G. Kirk ◽  
D. A. Williams ◽  
H. Ahmed
Keyword(s):  
Electron Microscopy ◽  
Integrated Circuits ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Cross Sectional ◽  
Transmission Electron ◽  
A New Technique ◽  
Sectional Analysis ◽  
Selection Of ◽  
Better Than

ABSTRACTA new technique using a focused ion beam has been developed for the fabrication of transmission electron microscopy specimens in pre-selected regions. The method has been proven in the fabrication of both cross-sectional and planar specimens, with no induced artefacts. The lateral accuracy achievable in the selection of an area for cross-sectional analysis is better than one micrometre. The technique has been applied to a number of silicon and III-V based integrated circuits, and is expected to be suitable for many other materials and structures.

Amorphization phenomenon in Ni/amorphous Si multilayers

1994 ◽  
Vol 9 (2) ◽  
pp. 401-405 ◽  
Author(s):  
W.H. Wang ◽  
W.K. Wang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Solid State ◽  
Amorphous Structure ◽  
Cross Sectional ◽  
Modulation Period ◽  
Transmission Electron ◽  
Amorphous Si ◽  
Means Of Transmission ◽  
State Amorphization

Interfacial reactions of Ni/amorphous Si(a-Si) multilayers are studied by means of transmission electron microscopy (TEM) and cross-sectional transmission electron microscopy (XTEM). Transformation from a crystalline to an amorphous structure has been observed in as-deposited Ni/a-Si multilayers with small modulation periods. This phenomenon is suggested to be due to interdiffusion-induced solid state amorphization which is facilitated by the high density of interface in the shorter modulation period multilayers. A thermodynamic and kinetic explanation is given for this phenomenon.

scholarly journals The Effects of High Temperature Exposure on the Durability of Thermal Barrier Coatings

2000 ◽  
Author(s):  
N. M. Yanar ◽  
M. J. Stiger ◽  
F. S. Pettit ◽  
G. H. Meier
Keyword(s):  
Electron Microscopy ◽  
Bond Coat ◽  
Physical Vapor Deposition ◽  
Thermally Grown Oxide ◽  
Phase Changes ◽  
Cross Sectional ◽  
Outward Diffusion ◽  
Bond Coats ◽  
Platinum Aluminide ◽  
Temperature Exposure

Abstract Yttria-stabilized Zirconia (YSZ) coatings deposited by electron beam physical vapor deposition on platinum aluminide and NiCoCrAlY bond coats on single crystal superalloy substrates have been oxidized at temperatures between 1000 and 1200°C in air. The cyclic oxidation lives of the systems with platinum aluminide bond coats were substantially longer than those with NiCoCrAlY bond coats. The thermally grown oxide (TGO) that develops between the bond coat and the TBC during oxidation, as well as the bond coat and the TBC adjacent to the TGO, have been examined in detail using optical metallography, scanning electron microscopy (SEM), and cross-sectional transmission electron microscopy (XTEM). The YSZ is observed to undergo significant amounts of sintering. The TGO grows by the inward diffusion of oxygen and the outward diffusion of aluminum. In some cases, the outward growth component incorporates some of the TBC into the TGO. The depletion of aluminum results in phase changes in the bond coats. Failure of the TBCs occurs after fixed amounts of oxidation which result in increasing amounts of elastic energy being stored in the TGO and YSZ as well as degradation of the TGO-bond coat interface. The fracture path changed as a function of exposure time and temperature with larger amounts of separation occurring at the TGO/BC interface for higher temperatures and longer exposures in dry air. Failure can be accelerated in the presence of water vapor, particularly if spinel formation is induced. Fracture occurs primarily in the oxides, in this case. The fracture surface for systems with platinum aluminide bond coats often contains precipitates, which are rich in refractory metals. These features do not appear to be prevalent with NiCoCrAlY bond coats.

Microstructure of laser-irradiated, conducting Kapton polyimide

1995 ◽  
Vol 53 ◽  
pp. 502-503
Author(s):  
D. L. Callahan ◽  
Z. Ball ◽  
H. M. Phillips ◽  
R. Sauerbrey
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Film Surface ◽  
Cross Sectional ◽  
General Utility ◽  
Transmission Electron ◽  
Considerable Debate ◽  
Potential Applications

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.

Ion thinning of integrated circuit transverse specimens for transmission electron microscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1426-1427
Author(s):  
F. Shaapur
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Integrated Circuit ◽  
Substrate Surface ◽  
Homogeneous Material ◽  
Material System ◽  
Ion Milling ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Motion Profile

Non-uniform ion-thinning of heterogenous material structures has constituted a fundamental difficulty in preparation of specimens for transmission electron microscopy (TEM). A variety of corrective procedures have been developed and reported for reducing or eliminating the effect. Some of these techniques are applicable to any non-homogeneous material system and others only to unidirectionalfy heterogeneous samples. Recently, a procedure of the latter type has been developed which is mainly based on a new motion profile for the specimen rotation during ion-milling. This motion profile consists of reversing partial revolutions (RPR) within a fixed sector which is centered around a direction perpendicular to the specimen heterogeneity axis. The ion-milling results obtained through this technique, as studied on a number of thin film cross-sectional TEM (XTEM) specimens, have proved to be superior to those produced via other procedures.XTEM specimens from integrated circuit (IC) devices essentially form a complex unidirectional nonhomogeneous structure. The presence of a variety of mostly lateral features at different levels along the substrate surface (consisting of conductors, semiconductors, and insulators) generally cause non-uniform results if ion-thinned conventionally.

High-Resolution Cryo-Electron Microscopy of Biological Macromolecules

1990 ◽  
Vol 48 (1) ◽  
pp. 126-127
Author(s):  
Yoshinori Fujiyoshi
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Diffraction Pattern ◽  
Superfluid Helium ◽  
Copper Phthalocyanine ◽  
Optical Diffraction ◽  
Irradiation Damage ◽  
Biological Macromolecules ◽  
Cross Sectional ◽  
Instrumental Resolution

The resolution of direct images of biological macromolecules is normally restricted to far less than 0.3 nm. This is not due instrumental resolution, but irradiation damage. The damage to biological macromolecules may expect to be reduced when they are cooled to a very low temperature. We started to develop a new cryo-stage for a high resolution electron microscopy in 1983, and successfully constructed a superfluid helium stage for a 400 kV microscope by 1986, whereby chlorinated copper-phthalocyanine could be photographed to a resolution of 0.26 nm at a stage temperature of 1.5 K. We are continuing to develop the cryo-microscope and have developed a cryo-microscope equipped with a superfluid helium stage and new cryo-transfer device.The New cryo-microscope achieves not only improved resolution but also increased operational ease. The construction of the new super-fluid helium stage is shown in Fig. 1, where the cross sectional structure is shown parallel to an electron beam path. The capacities of LN2 tank, LHe tank and the pot are 1400 ml, 1200 ml and 3 ml, respectively. Their surfaces are placed with gold to minimize thermal radiation. Consumption rates of liquid nitrogen and liquid helium are 170 ml/hour and 140 ml/hour, respectively. The working time of this stage is more than 7 hours starting from full LN2 and LHe tanks. Instrumental resolution of our cryo-stage cooled to 4.2 K was confirmed to be 0.20 nm by an optical diffraction pattern from the image of a chlorinated copper-phthalocyanine crystal. The image and the optical diffraction pattern are shown in Fig. 2 a, b, respectively.

Devitrification products of rapidly solidified Ni-Nb amorphous alloys.

1990 ◽  
Vol 48 (4) ◽  
pp. 950-951
Author(s):  
G. A. Bertero ◽  
W.H. Hofmeister ◽  
N.D. Evans ◽  
J.E. Wittig ◽  
R.J. Bayuzick
Keyword(s):  
Electron Microscopy ◽  
Amorphous Structure ◽  
Sulphuric Acid Solution ◽  
X Ray Diffraction ◽  
High Fracture ◽  
Transmission Electron ◽  
Xrd Techniques ◽  
Rapidly Solidified ◽  
Electromagnetically Levitated

Rapid solidification of Ni-Nb alloys promotes the formation of amorphous structure. Preliminary results indicate promising elastic properties and high fracture strength for the metallic glass. Knowledge of the thermal stability of the amorphus alloy and the changes in properties with temperature is therefore of prime importance. In this work rapidly solidified Ni-Nb alloys were analyzed with transmission electron microscopy (TEM) during in-situ heating experiments and after isothermal annealing of bulk samples. Differential thermal analysis (DTA), scanning electron microscopy (SEM) and x-ray diffraction (XRD) techniques were also used to characterize both the solidification and devitrification sequences.Samples of Ni-44 at.% Nb were electromagnetically levitated, melted, and rapidly solidified by splatquenching between two copper chill plates. The resulting samples were 100 to 200 μm thick discs of 2 to 3 cm diameter. TEM specimens were either ion-milled or alternatively electropolished in a methanol-10% sulphuric acid solution at 20 V and −40°C.

TEM Sample Preparation Tricks for Advanced DRAMs

2015 ◽  
Author(s):  
Ching Shan Sung ◽  
Hsiu Ting Lee ◽  
Jian Shing Luo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Integrated Circuit ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Characterization Of Materials

Abstract Transmission electron microscopy (TEM) plays an important role in the structural analysis and characterization of materials for process evaluation and failure analysis in the integrated circuit (IC) industry as device shrinkage continues. It is well known that a high quality TEM sample is one of the keys which enables to facilitate successful TEM analysis. This paper demonstrates a few examples to show the tricks on positioning, protection deposition, sample dicing, and focused ion beam milling of the TEM sample preparation for advanced DRAMs. The micro-structures of the devices and samples architectures were observed by using cross sectional transmission electron microscopy, scanning electron microscopy, and optical microscopy. Following these tricks can help readers to prepare TEM samples with higher quality and efficiency.

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