On temperature dependence of deformation mechanism and the brittle–ductile transition in semiconductors

1999 ◽  
Vol 14 (7) ◽  
pp. 2783-2793 ◽  
Author(s):  
P. Pirouz ◽  
A. V. Samant ◽  
M. H. Hong ◽  
A. Moulin ◽  
L. P. Kubin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Shear Stress ◽  
Deformation Mechanism ◽  
Low Temperatures ◽  
Partial Dislocations ◽  
Brittle Ductile Transition ◽  
Transmission Electron ◽  
Literature Evidence ◽  
Critical Resolved Shear Stress

Recent deformation experiments on semiconductors have shown the occurrence of a break in the variation of the critical resolved shear stress of the crystal as a function of temperature. These and many other examples in the literature evidence a critical temperature at which a transition occurs in the deformation mechanism of the crystal. In this paper, the occurrence of a similar transition in two polytypes of SiC is reported and correlated to the microstructure of the deformed crystals investigated by transmission electron microscopy, which shows evidence for partial dislocations carrying the deformation at high stresses and low temperatures. Based on these results and data in the literature, the explanation is generalized to other semiconductors and a possible relationship to their brittle–ductile transition is proposed.

Epitaxial Growth of NiSi2 on (011)Si

1983 ◽  
Vol 25 ◽  
Author(s):  
L.J. Chen ◽  
W.T. Lin ◽  
M.B. Chang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Shear Stress ◽  
Epitaxial Growth ◽  
Expected Value ◽  
Edge Type ◽  
Average Spacing ◽  
Transmission Electron ◽  
Interfacial Dislocations ◽  
Critical Resolved Shear Stress

ABSTRACTEpitaxial growth of NiSi2 on (011)Si was investigated by the transmission electron microscopy. Both epitaxial and twin related NiSi2 were formed, with the former being predominant, in samples annealed at 850°C for 1/2 h. The silicides were faceted with {111} interfaces being more prominent than {100} interfaces. Interfacial dislocations were found to be of edge type with 1/6<112> Burgers vectors. The average spacing is about 700 Å which is very close to the theoretically expected value 670 Å.The absence of twins formed on (111) and (111) planes for (011) samples as well as the results obtained for (001) and (111) specimens suggest that there exists a critical resolved shear stress at the interface for the initiation of the formation of twin related NiSi2.

Quantitative transmission electron microscopy of small agglomerates in HF-O

1978 ◽  
Vol 36 (1) ◽  
pp. 336-337
Author(s):  
M. Rühle ◽  
G. Elssner ◽  
O. Ruano
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Plastic Deformation ◽  
Shear Stress ◽  
Physical Properties ◽  
Temperature Dependence ◽  
Hexagonal Lattice ◽  
Transmission Electron ◽  
Critical Resolved Shear Stress

High amounts of gases or carbon are soluble on interstitial sites of the hexagonal lattice of hafnium. The gas atoms influence nearly all physical properties; e.g., the critical resolved shear stress τ (CRSS) is drastically increased with an increasing content of gas atoms. Different authors measured the temperature dependence of τ for different 0 concentrations (cO ≲ 1.5 at%). The CRSS increases strongly with decreasing measuring temperature T. Ruano and Elssner concluded intuitively from the non continious shape of the τ-T curve, that besides the interstitially solved single gas atoms also agglomerates of gas atoms should be present in the specimens. These agglomerates act as strong barriers against plastic deformation. - A superposition of the 2 types of barriers (single interstitial gas atoms and agglomerates) could explain the shape of the τ-T curve. TEM studies were performed to prove this assumption of the existence of agglomerates. Hafnium specimens with different 0 content (0.13, 0.65 and 1.17 at%0) were electrolytically thinned and investigated with a Siemens ELMISKOP 102 operated at 125 kV.

Nature of Slip in γ-Titanium Aluminide Above the Yield Stress Anomaly Temperature

1998 ◽  
Vol 552 ◽  
Author(s):  
S. Jiao ◽  
N. Bird ◽  
P. B. Hirsch ◽  
G. Taylor
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Shear Stress ◽  
Yield Stress ◽  
Titanium Aluminide ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Critical Resolved Shear Stress

ABSTRACTCrystals of γ-TiAl, containing ∼54.5 at% Al, with various orientations were deformed at different temperatures and examined by transmission electron microscopy (TEM). It was found that while in many cases slip and climb of ordinary dislocations tend to predominate, slip by [001] dislocations can be important also. The occurrence of [001] slip has not been reported before. The values of critical resolved shear stress were determined and strong locks on [001] dislocations have been identified as local segments of ½ ⟨112] dislocations arising from interactions between [001] and ½⟨110] dislocations.

Structural Properties of Amorphous Silicon Produced by Electron Irradiation

1999 ◽  
Vol 557 ◽  
Author(s):  
J. Yamasaki ◽  
S. Takeda
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Distribution Function ◽  
Structural Properties ◽  
Electron Irradiation ◽  
Low Temperatures ◽  
Crystalline Silicon ◽  
Transmission Electron ◽  
Amorphous Si ◽  
Means Of Transmission

AbstractThe structural properties of the amorphous Si (a-Si), which was created from crystalline silicon by 2 MeV electron irradiation at low temperatures about 25 K, are examined in detail by means of transmission electron microscopy and transmission electron diffraction. The peak positions in the radial distribution function (RDF) of the a-Si correspond well to those of a-Si fabricated by other techniques. The electron-irradiation-induced a-Si returns to crystalline Si after annealing at 550°C.

Dislocations and stacking faults in stainless steel

1957 ◽  
Vol 240 (1223) ◽  
pp. 524-538 ◽  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stainless Steel ◽  
Grain Boundaries ◽  
Stacking Faults ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Thin Sections ◽  
Partial Dislocations ◽  
Transmission Electron

Further experiments by transmission electron microscopy on thin sections of stainless steel deformed by small amounts have enabled extended dislocations to be observed directly. The arrangement and motion of whole and partial dislocations have been followed in detail. Many of the dislocations are found to have piled up against grain boundaries. Other observations include the formation of wide stacking faults, the interaction of dislocations with twin boundaries, and the formation of dislocations at thin edges of the foils. An estimate is made of the stacking-fault energy from a consideration of the stresses present, and the properties of the dislocations are found to be in agreement with those expected from a metal of low stacking-fault energy.

Effects of Dopants on the Nucleation and Growth of NiSi2 on Silicon

1987 ◽  
Vol 94 ◽  
Author(s):  
S. W. Lu ◽  
C. W. Nieh ◽  
J. J. Chu ◽  
L. J. Chen
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Low Temperatures ◽  
Nucleation And Growth ◽  
The Other ◽  
Size Factor ◽  
Atomic Size ◽  
Nickel Thin Films ◽  
Transmission Electron

ABSTRACTThe influences of implantation impurities, including BF2, B, F, As and P on the formation of epitaxial NiSi2 in nickel thin films on ion-implanted silicon have been investigated by transmission electron microscopy.The presence of BF2, B, and F atoms was observed to promote the epitaxial growth of NiSi2 at low temperatures. Little or no effect on the formation of NiSi2 was found in samples implanted with As or P ions.The results indicated that the influences of the implantation impurities are not likely to be electronic in origin. Good correlation, on the other hand, was found between the atomic size factor and resulting stress and NiSi2 epitaxy at low temperatures.

Dislocations around precipitates in AlGaN epilayers

2002 ◽  
Vol 17 (8) ◽  
pp. 2007-2011 ◽  
Author(s):  
Junyong Kang ◽  
Shin Tsunekawa ◽  
Atsuo Kasuya
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Shear Stress ◽  
Dislocation Loop ◽  
Edge Dislocation ◽  
Concentration Change ◽  
Homogeneous Shear ◽  
Transmission Electron ◽  
Shape And Size ◽  
Chemical Force

Dislocations around precipitates in undoped AlGaN were investigated by transmission electron microscopy. The dislocation images were taken under different diffraction conditions. The dislocations are classified into two types, a pure edge dislocation loop and a close-;coiled helical dislocation. Both types of dislocations were found to depend on the shape and size of the precipitate sources. It is suggested that the pure edge dislocation loop results from homogeneous shear stress and the close-;coiled helical dislocation is caused by spherically symmetrical stress concentration at round ends of the precipitates and chemical force due to defect concentration change.

Synthesis of Carbon Nanosphere at Low Temperatures Based on Bamboo Fiber

2019 ◽  
Vol 966 ◽  
pp. 163-168 ◽  
Author(s):  
Yulia Kirana Lahsmin ◽  
Dahlang Tahir ◽  
Bualkar Abdullah ◽  
Sultan Ilyas ◽  
Inayatul Mutmainna
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Temperatures ◽  
Potassium Hydroxide ◽  
Bamboo Fiber ◽  
X Ray Diffraction ◽  
Activation Temperature ◽  
X Ray ◽  
Transmission Electron ◽  
Bamboo Fibers

Carbon Nanosphere (CNs) has been successfully synthesized from bamboo fibers at low temperatures by carbonization and activation. For activation used Potassium Hydroxide (KOH) at temperature 105°C, 155°C, 205°C, 255°C and 305°C. X-Ray Diffraction (XRD) spectra shows hexagonal and amorphous phase and Fourier Transform Infrared (FTIR) spectra shows decrease C-O bond with increasing activation temperature. Transmission Electron Microscopy (TEM) image for activation temperature of 105°C confirmed that sources the formation of Carbon Nanosphere. In this study shows bamboo fiber has a high potential as a carbon nanosphere material.

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