Characterization of Growth Defects in CdZnTe Single Crystals by Synchrotron White Beam X-ray Topography

1995 ◽  
Vol 378 ◽  
Author(s):  
H. Chung ◽  
B. Raghothamachar ◽  
J. Wu ◽  
M. Dudley ◽  
D. J. Larson ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Single Crystals ◽  
Thermal Stresses ◽  
Structural Defects ◽  
Dislocation Slip ◽  
Accelerated Cooling ◽  
Cooling Rates ◽  
X Ray ◽  
Slip Bands ◽  
White Beam

AbstractSynchrotron white beam X-ray topography has been used to characterize structural defects in microgravity grown CdZnTe single crystals. Defects such as dislocations, slip bands, 180° rotation twins, precipitates and subgrain boundaries are observed but their density is much lower than those in crystals grown under normal gravity. The observed results also indicate that the defect structures of the as grown crystals are strongly influenced by cooling rates. X-ray transmission topographs recorded from regions grown at different cooling rates show that the dislocation density in rapidly cooled regions is higher than that in slowly cooled regions. The formation of dislocations is presumably attributed to the thermal stress caused by accelerated cooling rates, which is greater than the critical resolved shear stress. As the cooling rate is accelerated, the magnitude of thermal stress is increased and more dislocations are formed to relieve the accumulated lattice strain. In addition, if the cooling rates are increased further, the accentuated thermal stresses can give rise to more pronounced deformation processes, comprising the formation of dislocation slip bands, as confirmed by the extensive slip bands revealed by the X-ray reflection topographs.

Characterization of structural defects in MLEK grown InP single crystals using synchrotron white beam X-ray topography

1997 ◽  
Vol 174 (1-4) ◽  
pp. 230-237 ◽  
Author(s):  
H. Chung ◽  
W. Si ◽  
M. Dudley ◽  
A. Anselmo ◽  
D.F. Bliss ◽  
...  
Keyword(s):  
Single Crystals ◽  
Structural Defects ◽  
X Ray ◽  
White Beam

Synchrotron White Beam Topography Studies of Screw Dislocations in 6H-Sic Single Crystals

1994 ◽  
Vol 375 ◽  
Author(s):  
S. Wang ◽  
M. Dudley ◽  
C. H. Carter ◽  
V. F. Tsvetkov ◽  
C. Fazi
Keyword(s):  
Single Crystals ◽  
Structural Defects ◽  
Device Performance ◽  
Topographic Image ◽  
X Ray Diffraction ◽  
Screw Dislocations ◽  
X Ray ◽  
White Beam ◽  
Line Defects ◽  
Kinematical Theory

AbstractSynchrotron white beam X-ray topography, along with optical microscopy and scanning electron microscopy, has been used to characterize structural defects which are potentially detrimental to device performance in PVT 6H-SiC single crystals. Line defects running along the [0001] axis, known as “micropipes”, were studied extensively. Detailed analysis of topographic image contrast associated with “micropipes”, based on the kinematical theory of X-ray diffraction, established that the so-called “micropipes” are screw dislocations with large Burgers vectors.

Characterization of Growth Defects in ZnTe Single Crystals

1994 ◽  
Vol 299 ◽  
Author(s):  
W. Zhou ◽  
J. Wu ◽  
M. Dudley ◽  
C.H. Su ◽  
M.P. Volz ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Dislocation Cell ◽  
Interference Microscopy ◽  
Dislocation Slip ◽  
Asymmetric Distribution ◽  
Twin Boundaries ◽  
X Ray ◽  
Atomic Structures ◽  
Slip Bands ◽  
White Beam

Abstract(111) wafers sliced from a boule of ZnTe grown by horizontal physical vapor transport (PVT) have been characterized using synchrotron white beam X-ray topography. The growth axis was about 6° off [311]. The presence of dislocation slip bands, subgrain structures and [111] axis 180° rotational twins were revealed. The slip bands were observed to break up the ordered dislocation cell structures comprising the subgrain boundaries. The initiation of slip at regions of stress concentration at the junctions of subgrain boundaries and twin boundaries was observed. The asymmetric distribution of slip bands either side of the twinned region of crystal suggests that twin boundaries can act as barriers for slip. Several types of detailed twin boundary configuration were determined from the topographs. Using a combination of white beam X-ray topography and Nomarski interference microscopy, the three dimensional shapes of the twin boundaries were determined. Approximate atomic structures at these boundaries are presented.

Characterization of Growth Defects in ZnTe Single Crystals

1993 ◽  
Vol 302 ◽  
Author(s):  
W. Zhou ◽  
J. Wu ◽  
M. Dudley ◽  
C.H. Su ◽  
M.P. Volz ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Dislocation Cell ◽  
Interference Microscopy ◽  
Dislocation Slip ◽  
Asymmetric Distribution ◽  
Twin Boundaries ◽  
X Ray ◽  
Atomic Structures ◽  
Slip Bands ◽  
White Beam

ABSTRACT(111) wafers sliced from a boule of ZnTe grown by horizontal physical vapor transport (PVT) have been characterized using synchrotron white beam X-ray topography. The growth axis was about 6° off [311]. The presence of dislocation slip bands, subgrain structures and [111] axis 180° rotational twins were revealed. The slip bands were observed to break up the ordered dislocation cell structures comprising the subgrain boundaries. The initiation of slip at regions of stress concentration at the junctions of subgrain boundaries and twin boundaries was observed. The asymmetric distribution of slip bands either side of the twinned region of crystal suggests that twin boundaries can act as barriers for slip. Several types of detailed twin boundary configuration were determined from the topographs. Using a combination of white beam X-ray topography and Nomarski interference microscopy, the three dimensional shapes of the twin boundaries were determined. Approximate atomic structures at these boundaries are presented.

Studies of Interface Demarcation and Structural Defects in Ga Doped Ge Single Crystals Using Synchrotron White Beam X-Ray Topography

1996 ◽  
Vol 437 ◽  
Author(s):  
H. Chung ◽  
B. Raghothamachar ◽  
W. Zhou ◽  
M. Dudley ◽  
D. C. Gillies
Keyword(s):  
Single Crystals ◽  
Reciprocal Lattice ◽  
Dislocation Cell ◽  
Structural Defects ◽  
Interface Plane ◽  
Lattice Vector ◽  
Synchrotron Source ◽  
X Ray ◽  
Correct Orientation ◽  
White Beam

AbstractSynchrotron White Beam X-ray Topography (SWBXT) has been applied to the characterization of marked growth interfaces in Ga doped Ge single crystals. The techniques employed in interface demarcation include modifications of the cold zone temperature, mechanical pulsing and Peltier pulsing. As revealed by our observations, the visibility of growth interfaces is a sensitive function of diffraction conditions. A combination of the correct orientation of the active reciprocal lattice vector with respect to the interface plane and the necessary strain sensitivity controlled by the rocking curve width of the reflection are proved to be important for interface visibility. This can easily be achieved by using synchrotron radiation since the tunability of the synchrotron source provides great flexibility in the choice of proper diffraction conditions. Structural defects such as small-angle tilt boundaries and dislocation cell structures were also observed. The formation mechanism of these defects will be discussed. Direct evidence of dislocations present in the seed crystal propagating into the as-grown crystal through the melt-back interface during crystal growth was also obtained.

Synchrotron white beam x-ray topography characterization of structural defects in microgravity and ground-based CdZnTe crystals

1996 ◽  
Author(s):  
Hua Chung ◽  
Balaji Raghothamachar ◽  
Michael Dudley ◽  
David J. Larson, Jr.
Keyword(s):  
Structural Defects ◽  
X Ray ◽  
White Beam

Characterization of Defect Structures in 3C-SiC Single Crystals Using Synchrotron White Beam X-ray Topography

1996 ◽  
Vol 423 ◽  
Author(s):  
W. Huang ◽  
M. Dudley ◽  
C. Fazi
Keyword(s):  
Single Crystals ◽  
Stacking Faults ◽  
Interference Microscopy ◽  
Defect Structures ◽  
Growth Sector ◽  
X Ray ◽  
Partial Dislocations ◽  
White Beam ◽  
Transmission And Reflection

AbstractDefect structures in (111) 3C-SiC single crystals, grown using the Baikov technique, have been studied using Synchrotron White Beam X-ray Topography (SWBXT). The major types of defects include complex growth sector boundary structures, double positioning twins, stacking faults on { 111 } planes, inclusions and dislocations (including growth dislocations and partial dislocations bounding stacking faults). Detailed stacking fault and double positioning twin configurations are determined using a combination of Nomarski interference microscopy, SEM and white beam x-ray topography in both transmission and reflection geometries. Possible defect generation phenomena are discussed.

Characterization of Defect Structures in SiC Single Crystals Using Synchrotron X-Ray Topography

1993 ◽  
Vol 307 ◽  
Author(s):  
S. Wang ◽  
M. Dudley ◽  
C. Carter ◽  
D. Asbury ◽  
C. Fazit
Keyword(s):  
Detailed Analysis ◽  
Single Crystals ◽  
Basal Plane ◽  
Defect Structures ◽  
Dislocation Generation ◽  
Screw Dislocations ◽  
X Ray ◽  
White Beam

ABSTRACTSynchrotron white beam X-ray topography has been used to characterize defect structures in 6H-SiC wafers grown on (0001) seeds. Two major types of defects are observed: super screw dislocations approximately perpendicular to the basal plane and dislocation networks lying in the basal plane. The super screw dislocations, which have open cores, are growth dislocations. These dislocations act as sources and/or sinks for the glide dislocation networks. Detailed analysis and discussion of dislocation generation phenomena and Burgers vectors will be presented.

Structural Defect Studies of Semiconductor Crystals with Laue Topography

2011 ◽  
Vol 178-179 ◽  
pp. 360-365 ◽  
Author(s):  
Alexander Gröschel ◽  
Johannes Will ◽  
Christoph Bergmann ◽  
Hannes Grillenberger ◽  
Stefan Eichler ◽  
...  
Keyword(s):  
High Energy ◽  
Structural Defects ◽  
Dislocation Network ◽  
X Ray ◽  
Gaas Wafer ◽  
Semiconductor Crystals ◽  
White Beam ◽  
Oxygen Precipitates ◽  
Si Wafer

A defocused Laue diffractometer setup operating with the white beam of a high energy X-ray tube has been used for a topographic visualization of structural defects in semiconductor wafers. The laboratory white beam X-ray topograph of a Czochralski Si wafer with oxygen precipitates grown in an annealing process is compared to a μPCD image. Further, the dislocation network in a VGF GaAs wafer is studied under thermal annealing up to 1140°C and the in-situ capability of the setup is demonstrated.

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