Partial Dislocations and Critical Thicknesses for Strained Layer Relaxation

1992 ◽  
Vol 263 ◽  
Author(s):  
D. M. Hwang ◽  
R. Bhat ◽  
S. A. Schwarz ◽  
C. Y. Chen
Keyword(s):  
Electron Microscopy ◽  
Energy Minimization ◽  
Critical Thickness ◽  
Stacking Faults ◽  
Standard Free Energy ◽  
Strained Layers ◽  
Partial Dislocations ◽  
Transmission Electron ◽  
Perfect Dislocation ◽  
Fcc Structure

ABSTRACTPartial dislocations and their associated stacking faults are identified as the primary defects responsible for the initial relaxation of tensile-strained layers of fcc structure. The critical thickness for the formation of 90° partial dislocations at the strained interface is almost a factor of two smaller than that predicted for the formation of 60° perfect dislocation. Microstructures revealed by transmission electron microscopy from strained layers of various lattice mismatches and thicknesses agree with the prediction of the standard free-energy minimization model.

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.

Tem Study of the Structure of Mbe GaAs Layers Grown at Low Temperature

1990 ◽  
Vol 198 ◽  
Author(s):  
Zuzanna Liliental-Weber
Keyword(s):  
Electron Microscopy ◽  
Low Temperature ◽  
Molecular Beam ◽  
Critical Thickness ◽  
Stacking Faults ◽  
Structural Quality ◽  
Crystalline Perfection ◽  
Transmission Electron ◽  
Low Temperature Gaas

ABSTRACTThe structural quality of GaAs layers grown at 200°C by molecular beam epitaxy (MBE) was investigated by transmission electron microscopy (TEM). We found that a high crystalline perfection can be achieved in the layers grown at this low temperature for thickness up to 3 μm. In some samples we observed pyramid-shaped defects with polycrystalline cores surrounded by microtwins, stacking faults and dislocations. The size of these cores increased as the growth temperature was decreased and as the layer thickness was increased. The upper surface of layers with pyramidal defects became polycrystalline at a critical thickness of the order of 3μm. We suggested that the low-temperature GaAs becomes polycrystalline at a critical thickness either because of a decrease in substrate temperature during growth or because strain induced by excess As incorporated in these layers leads to the formation of misoriented GaAs nuclei, thereby initiating polycrystalline growth. The pyramidal shape of the defects results from a growth-rate hierarchy of the low index planes in GaAs.

Overlapping Shockley/Frank Faults in 4H-SiC PiN Diodes

2006 ◽  
Vol 527-529 ◽  
pp. 383-386 ◽  
Author(s):  
Mark E. Twigg ◽  
Robert E. Stahlbush ◽  
Peter A. Losee ◽  
Can Hua Li ◽  
I. Bhat ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Light Emission ◽  
Stacking Faults ◽  
Dark Field ◽  
Pin Diodes ◽  
Plan View ◽  
Planar Defects ◽  
Burgers Vector ◽  
Partial Dislocations ◽  
Transmission Electron

Using light emission imaging (LEI), we have determined that not all planar defects in 4H-SiC PiN diodes expand in response to bias. Accordingly, plan-view transmission electron microscopy (TEM) observations of these diodes indicate that these static planar defects are different in structure from the mobile stacking faults (SFs) that have been previously observed in 4H-SiC PiN diodes. Bright and dark field TEM observations reveal that such planar defects are bounded by partial dislocations, and that the SFs associated with these partials display both Frank and Shockley character. That is, the Burgers vector of such partial dislocations is 1/12<4-403>. For sessile Frank partial dislocations, glide is severely constrained by the need to inject either atoms or vacancies into the expanding faulted layer. Furthermore, these overlapping SFs are seen to be fundamentally different from other planar defects found in 4H-SiC.

Dynamical Study of Dislocations and 4H → 3C Transformation Induced by Stress in (11-20) 4H-SiC

2005 ◽  
Vol 483-485 ◽  
pp. 299-302 ◽  
Author(s):  
Hosni Idrissi ◽  
Maryse Lancin ◽  
Joel Douin ◽  
G. Regula ◽  
Bernard Pichaud
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Etching ◽  
Stacking Faults ◽  
Sample Surface ◽  
Cubic Phase ◽  
Dynamical Study ◽  
Weak Beam ◽  
Partial Dislocations ◽  
Transmission Electron

4H-SiC samples were bent in compression mode at temperature ranging from 400°C to 700°C. The introduced-defects were identified by Weak Beam (WB) and High Resolution Transmission Electron Microscopy (HRTEM) techniques. They consist of double stacking faults bound by 30° Si(g) partial dislocations whose glide locally transforms the material in its cubic phase. The velocity of partial dislocations was measured after chemical etching of the sample surface. The formation and the expansion of the double stacking faults are discussed.

Transmission electron microscope investigation of indentation induced dislocation configurations on the (001) GaSb face

1994 ◽  
Vol 209 (3) ◽  
Author(s):  
J. Doerschel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Room Temperature ◽  
Stacking Faults ◽  
Electron Microscope Investigation ◽  
Partial Dislocations ◽  
Transmission Electron ◽  
Induced Dislocation

AbstractDislocation configurations induced by room temperature microindentations on the (001) face of GaSb (undoped and Te-doped) have been studied using high voltage transmission electron microscopy. Perfect and partial dislocations could be found in all four arms of the dislocation rosette around the indent. Microtwins and rarely single stacking faults are associated with the partials. Contrary to other binary III–V compounds, an “inverse” glide prism along the [1[unk]0]/[[unk]10] rosette arms is created and it is bounded by {111}

Initial Stage of Solid Phase Epitaxial Growth of GaAs Films on Vicinal Si (001) Substrate

1992 ◽  
Vol 263 ◽  
Author(s):  
W.K. Choo ◽  
I. Kim ◽  
J.Y. Lee ◽  
K.I. Cho ◽  
J.-L. Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Critical Thickness ◽  
Solid Phase ◽  
Three Dimensional ◽  
Stacking Faults ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Initial Stage ◽  
Gaas Films ◽  
Phase Proceeds

ABSTRACTThe initial stage of solid phase epitaxial (SPE) growth of GaAs films on the vicinal Si (001) substrate was investigated by high resolution transmission electron microscopy (H-RTEM). Cross-sectional [110] and [110] HRTEM images show that the SPE growth of crystalline GaAs islands from the amorphous phase proceeds via the formation of three-dimensional islands at the initial stage and islands' size and spacing are not critically dependent on the substrate tilt direction. The average vertical and lateral dimensions of islands were found to be 9 nm and 14 nm respectively, and the average island spacing was 10 nm. Moreover, many internal stacking faults (and/or microtwins) and a few dislocations have been already formed at this initial stage of growth. In addition, the critical thickness for misfit dislocation formation is found to depend upon the islands' lateral dimensions as well as the heights.

Stacking Fault Formation via 2D Nucleation in PVT Grown 4H-SiC

2015 ◽  
Vol 821-823 ◽  
pp. 85-89 ◽  
Author(s):  
Fang Zhen Wu ◽  
Huan Huan Wang ◽  
Yu Yang ◽  
Jian Qiu Guo ◽  
Balaji Raghothamachar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Opposite Sign ◽  
Stacking Faults ◽  
Stacking Fault ◽  
X Ray ◽  
Partial Dislocations ◽  
Transmission Electron ◽  
Structure Simulation ◽  
Simulation Results ◽  
Polytype Structure

Synchrotron white beam x-ray topography (SWBXT), synchrotron monochromatic beam x-ray topography (SMBXT), and high resolution transmission electron microscopy (HRTEM) studies have been carried out on stacking faults in PVT grown 4H-SiC crystal. Their fault vectors were determined by SWBXT to be 1/3<-1100>, 1/2<0001>, 1/6<-2203>, 1/12<4-403>, 1/12<-4403>. HRTEM studies reveal their similarity in stacking sequences as limited numbers of bilayers of 6H polytype structure. Simulation results of the two partial dislocations associated with the stacking faults in SMBXT images reveal the opposite sign nature of their Burgers vectors. A mechanism for stacking fault formation via 2D nucleation is postulated.

Stress-induced C14→C15 phase transformation in a Zr(Fe,Cr)2 Laves structured nanophase

2020 ◽  
Vol 53 (1) ◽  
pp. 222-225 ◽  
Author(s):  
Fusen Yuan ◽  
Chengze Liu ◽  
Fuzhou Han ◽  
Yingdong Zhang ◽  
Ali Muhammad ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Transformation ◽  
Phase Boundary ◽  
Shear Deformation ◽  
Orientation Relationship ◽  
Stacking Faults ◽  
Hexagonal Close Packed ◽  
Partial Dislocations ◽  
Transmission Electron

The C14 (hexagonal close-packed) and C15 (face-centred cubic) close-packed structures are found to coexist in an individual Zr(Fe,Cr)2 Laves structured nanophase in Zircaloy-4 alloy with shear deformation. The orientation relationship between C15 and C14 is [\bar 1 10]C15//[11\bar 20]C14 and (\bar 111)C15//(0001)C14. The stacking faults (SFs) in the C15 structure and the high-density SFs between C15 and C14 have been identified using transmission electron microscopy, which showed they originated on close-packed planes by emission of 1/6〈\bar 2 \bar 1\bar 1〉 Shockley partial dislocations from the phase boundary. Furthermore, the stress-induced C14→C15 phase transformation took place during the shear deformation.

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