Effect of temperature on metastable phases induced in silicon during nanoindentation

2008 ◽  
Vol 23 (1) ◽  
pp. 245-249 ◽  
Author(s):  
Rajnish K. Singh ◽  
Paul Munroe ◽  
Mark Hoffman
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Transformation ◽  
Crystalline Silicon ◽  
Metastable Phases ◽  
Effect Of Temperature ◽  
Berkovich Indenter ◽  
Transmission Electron ◽  
Indentation Imprint

Indentations were performed on silicon using a Berkovich indenter at loads up to 12 mN, at temperatures from 20 to 135 °C. Transmission electron microscopy revealed crystalline silicon phases in the residual indentation imprint at and above 35 °C. Also, the first reconfirmation of the occurrence of Si-VIII during unloading was observed at temperatures of 100 and 125 °C. Interestingly, at 125 °C a cavity was also observed, and an unidentifiable phase was observed at 135 °C. The observations show the strong effect of temperature on pressure-induced phase transformation in silicon.

Microstructural Evolution of Nickel Induced Crystallization of Amorphous Silicon

2002 ◽  
Vol 715 ◽  
Author(s):  
Kyu Ho Park ◽  
Young Woo Jeong ◽  
Hyun Ja Kwon ◽  
Jeong Soo Lee ◽  
Binn Kim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Transformation ◽  
Amorphous Silicon ◽  
Microstructural Evolution ◽  
Crystalline Silicon ◽  
Transmission Electron ◽  
Si Films ◽  
Induced Crystallization

AbstractThe Ni silicide-mediated phase transformation of amorphous to crystalline silicon (c-Si) was studied using transmission electron microscopy. Amorphous silicon (a-Si) films coated with very thin Ni layer (∼10-1Å) were annealed at various temperatures. Randomly oriented NiSi2 precipitates were observed in the Ni deposited a-Si film annealed at 400°C. The nucleation of the epitaxial c-Si has occurred on the {111} faces of the octahedral NiSi2 precipitate at 430°C and then caused to the variation in the shape of the NiSi2 precipitates. During the growth of c-Si, the needle-like morphology developed from the migration of NiSi2 precipitates through the a-Si matrix leaving a trail of c-Si. The collision of a migrating NiSi2 precipitate with a stationary NiSi2 precipitates in the a-Si film gave rise to the change in the morphology of the growing Si grain and the formation of additional c-Si needles on variants of the <111> direction.

Nucleation of Disorder in Fe3Al Alloys

1967 ◽  
Vol 25 ◽  
pp. 312-313
Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Antiphase Domain ◽  
Effect Of Temperature ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Higher Temperature ◽  
The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

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.

Nano-Thermometry: Transmission Electron Microscopy of Femtosecond Laser Irradiated Co/Si Multilayer Thin Foils

2005 ◽  
Vol 899 ◽  
Author(s):  
Yoosuf Picard ◽  
Steven M. Yalisove
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Amorphous Silicon ◽  
Heat Dissipation ◽  
Crystalline Silicon ◽  
Pulse Length ◽  
Multilayer Systems ◽  
Hole Edge ◽  
Thin Foils ◽  
Transmission Electron

AbstractPre-thinned foils composed of amorphous silicon and polycrystalline cobalt were irradiated using femtosecond pulse-length lasers at fluences sufficient for ablation (material removal). The resultant ablated hole and surrounding vicinity was studied using transmission electron microscopy to determine modifications to the structure. Evidence of cobalt silicide formation was observed within a 3 micron radius of the laser hole edge by use of selected area electron diffraction (SAED). In addition, elongated grains of crystalline silicon was observed within 500 nm of the laser hole edge, indicating melting of the amorphous silicon and heat dissipation slow enough to allow recyrstallization. This initial work demonstrates the use of pre-designed nanostructured multilayer systems as a method for nanoscale profiling of heat dissipation following pulsed laser irradiation.

Microstructure and Properties of Cu-Cr-Zr-Ag Alloy

2018 ◽  
Vol 941 ◽  
pp. 1613-1617 ◽  
Author(s):  
Li Jun Peng ◽  
Xu Jun Mi ◽  
Hao Feng Xie ◽  
Yang Yu ◽  
Guo Jie Huang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Phase Transformation ◽  
High Resolution ◽  
Aging Process ◽  
Precipitation Sequence ◽  
Transmission Microscopy ◽  
Transmission Electron ◽  
The Matrix

The Cr precipitation sequence in Cu-Cr-Zr-Ag alloy during the aging process at 450°C could be obtained by Transmission electron microscopy (TEM) and High-resolution transmission microscopy (HRTEM) in the study. The strengthening curve shows a unimodal type and the tensile strength trends to peak when the aged for 4h. The Cr phase transformation of Cu-Cr-Zr-Ag aged at 450°C is supersaturated solid sloution→G.P zones→fcc Cr phase→order fcc Cr phase→bcc Cr phase. The orientation relationship between bcc Cr precipitates and the matrix change from cube-on-cube to NW-OR.

Transmission Electron Microscopy Investigations of Metal-Impurity-Related Defects in Crystalline Silicon

2011 ◽  
Vol 178-179 ◽  
pp. 275-284 ◽  
Author(s):  
Michael Seibt ◽  
Philipp Saring ◽  
Philipp Hahne ◽  
Linda Stolze ◽  
M.A. Falkenberg ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Focused Ion Beam ◽  
Crystalline Silicon ◽  
Ion Beam ◽  
Extended Defects ◽  
Metal Impurity ◽  
Transmission Electron ◽  
Electron Beam Induced Current

This contribution summarizes recent efforts to apply transmission electron microscopy (TEM) techniques to recombination-active extended defects present in a low density. In order to locate individual defects, electron beam induced current (EBIC) is applied in situ in a focused ion beam (FIB) machine combined with a scanning electron microscope. Using this approach defect densities down to about 10cm-2 are accessible while a target accuracy of better than 50nm is achieved. First applications described here include metal impurity related defects in multicrystalline silicon, recombination and charge collection at NiSi2 platelets, internal gettering of copper by NiSi2 precipitates and site-determination of copper atoms in NiSi2.

Shock Synthesis of Nanocrystalline High -Pressure Phases in Semiconductors by High-Velocity Thermal Spray

2000 ◽  
Vol 638 ◽  
Author(s):  
R. Goswami ◽  
J. Parise ◽  
H. Herman ◽  
S. Sampath ◽  
R. Gambino ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Pressure ◽  
Thermal Spray ◽  
High Velocity ◽  
Metastable Phase ◽  
High Energy ◽  
Metastable Phases ◽  
Transmission Electron ◽  
Average Size

AbstractShock synthesis of nanocrystalline Si, Ge and CdTe was accomplished using high- velocity thermal spray. Si or Ge powders were injected into a high energy flame, created by a thermal spray gun, where the particles melt and accelerate to impact on a substrate. The shock wave generated by the sudden impact of the droplets propagated through the underlying deposits, which induces a phase transition to a high pressure form. The decompression of the high-pressure phase results in the formation of several metastable phases, as evidenced by transmission electron microscopy and x-ray diffraction studies. The peak pressure is estimated to be ≈23GPa with a pulse duration of 1-5 ns. Transmission electron microscopy revealed that the metastable phases of Si with a size range of 2 to 5 nm were dispersed within Si-I. In Ge, a metastable phase, ST-12, was observed. This is a decompression product of Ge-II which possesses the β-Sn type of structure. In the case of CdTe, a fine dispersion of hexagonal CdTe particles, embedded in cubic-CdTe with an average size of 2 nm was obtained.

In situ Transmission Electron Microscopy and Nanoindentation Studies of Phase Transformation and Pseudoelasticity of Shape-memory Titanium-nickel Films

2005 ◽  
Vol 20 (7) ◽  
pp. 1808-1813 ◽  
Author(s):  
X.-G. Ma ◽  
K. Komvopoulos
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Transformation ◽  
Shape Memory ◽  
Heating And Cooling ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Titanium Nickel ◽  
In Situ Heating

Transmission electron microscopy (TEM) and nanoindentation, both with in situ heating capability, and electrical resistivity measurements were used to investigate phase transformation phenomena and thermomechanical behavior of shape-memory titanium-nickel (TiNi) films. The mechanisms responsible for phase transformation in the nearly equiatomic TiNi films were revealed by heating and cooling the samples inside the TEM vacuum chamber. Insight into the deformation behavior of the TiNi films was obtained from the nanoindentation response at different temperatures. A transition from elastic-plastic to pseudoelastic deformation of the martensitic TiNi films was encountered during indentation and heating. In contrast to the traditional belief, the martensitic TiNi films exhibited a pseudoelastic behavior during nanoindentation within a specific temperature range. This unexpected behavior is interpreted in terms of the evolution of martensitic variants and changes in the mobility of the twinned structures in the martensitic TiNi films, observed with the TEM during in situ heating.

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