Conversion of Basal Plane Dislocations to Threading Edge Dislocations by High Temperature Annealing of 4H-SiC Epilayers

2012 ◽  
Vol 1433 ◽  
Author(s):  
Xuan Zhang ◽  
Hidekazu Tsuchida
Keyword(s):  
High Temperature ◽  
Basal Plane ◽  
Image Force ◽  
Line Tension ◽  
Grazing Incidence ◽  
High Temperature Annealing ◽  
X Ray ◽  
Before And After ◽  
Edge Dislocations ◽  
Epilayer Surface

ABSTRACTConversion of basal plane dislocations (BPDs) to threading edge dislocations (TEDs) has been observed in 4H-SiC epilayers by simple high temperature annealing. Grazing incidence reflection synchrotron X-ray topography was used to image the dislocations in the epilayers. By comparing the X-ray topographs before and after annealing, some of the BPDs were confirmed to convert to TEDs from the epilayer surface. The dislocation behaviors during annealing are explained and the mechanism of BPD conversion is discussed. It is argued that the conversion process is realized by constricted BPD segments cross-slipping to the prismatic plane driven by the image force and TED glide on its slip plane driven by the line tension. Certain kinetic processes may assist the formation of constrictions on the BPDs.

Improvement of the Crystalline Quality of β-Ga2O3 Films by High-Temperature Annealing

2012 ◽  
Vol 725 ◽  
pp. 273-276
Author(s):  
Motoki Takahara ◽  
Suguru Funasaki ◽  
Jyun Kudou ◽  
Isao Tsunoda ◽  
Kenichiro Takakura ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Crystalline Quality ◽  
High Temperature Annealing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Si Doped ◽  
Scanning Electron

For the purpose of improving the crystalline quality of undoped and Si doped β-Ga2O3 films, high temperature annealing at 900°C was performed. The crystalline quality of the films investigated using scanning electron microscopy and X-ray diffraction. Also the conductivity of the films is compared before and after the annealing. After the 900°C annealing, the XRD peaks intensity corresponding to β-Ga2O3 is increased. This result indicates that the crystalline quality improves by the high temperature annealing.

Simulation of threading dislocation images in X-ray topographs of silicon carbide homo-epilayers

2005 ◽  
Vol 38 (3) ◽  
pp. 442-447 ◽  
Author(s):  
W. M. Vetter ◽  
H. Tsuchida ◽  
I. Kamata ◽  
M. Dudley
Keyword(s):  
Basal Plane ◽  
Grazing Incidence ◽  
Threading Dislocation ◽  
Screw Dislocations ◽  
X Ray ◽  
Maximum Resolution ◽  
Reflection Geometry ◽  
Reflection Equations ◽  
Experimental Geometry ◽  
Edge Dislocations

Three types of dislocation are seen in homo-epilayers of SiC grown on 4H-SiC wafers with an 8° surface offcut: axial screw dislocations, basal plane dislocations propagated into the epilayer at an 8° inclination and threading edge dislocations. These types may be imaged by monochromatic synchrotron X-ray topography in the grazing-incidence reflection geometry using the 11\overline 28 reflection. Equations needed to apply the ray-tracing method of computer simulating X-ray topographic defect images in this experimental geometry were derived and used to simulate images of all three. Simulations for axial screw dislocations appear as white circles surrounded by narrow dark rings, and those for basal plane dislocations as linear white streaks, both consistent with experimental topographs. Simulations of the threading edge dislocations showed 4 µm wide white ovals with narrow arcs of dark contrast at their ends, inclined relative to the g vector of the topograph according to the sign of their Burgers vector. These images resembled the experimental topographs inasmuch as was possible at the maximum resolution of X-ray topographs.

Conversion of Basal Plane Dislocations to Threading Edge Dislocations by Annealing 4H-SiC Epilayers at High Temperatures

2013 ◽  
Vol 740-742 ◽  
pp. 601-604
Author(s):  
Xuan Zhang ◽  
Masahiro Nagano ◽  
Hidekazu Tsuchida
Keyword(s):  
Surface Morphology ◽  
Ion Implantation ◽  
Epitaxial Growth ◽  
High Temperatures ◽  
Basal Plane ◽  
Grazing Incidence ◽  
Conversion Ratio ◽  
Prismatic Plane ◽  
X Ray ◽  
Edge Dislocations

Basal plane dislocations (BPDs) converting to threading edge dislocations (TEDs) has been observed in 4H-SiC epilayers after thermal annealing at high temperatures. Grazing incidence reflection synchrotron X-ray topography was used to investigate the dislocation behaviors. It is argued that the conversion is achieved by constricted BPD segments cross-slipping to the prismatic plane and TED glide on its slip plane. Higher conversion ratio and better surface morphology were achieved by performing ion implantation and annealing before epitaxial growth.

Interfacial Chemical Reactions Between MoS2 Lubricants and Bearing Materials

1988 ◽  
Vol 140 ◽  
Author(s):  
J.S. Zabinski ◽  
B.J. Tatarchuk
Keyword(s):  
High Temperature ◽  
Single Crystals ◽  
Basal Plane ◽  
Iron Sulfide ◽  
Vacuum Annealing ◽  
High Temperature Annealing ◽  
Iron Sulfides ◽  
X Ray ◽  
Bearing Materials ◽  
Excess Sulfur

AbstractX-ray Photoelectron.pectroscopy (XPS) and Conversion Electron M6ssbauer bpectroscopy (CEMS) were used to examine iron that was deposited on the basal plane of MoS2 single crystals and subjected to vacuum annealing, oxidizing, and reducing environments. Iron either intercalated into the MoS2 structure or formed oriented iron sulfides depending on the level of excess sulfur in the MoS2 structure. CEMS data demonstrated that iron sulfide crystal structures preferentially aligned with respect to theMoS2 basal plane and that alignment, and potentially adhesion, could be variedby appropriate high temperature annealing procedures.

Contrast of Basal Plane and Threading Edge Dislocations in 4H-SiC by X-Ray Topography in Grazing Incidence Geometry

2008 ◽  
Vol 600-603 ◽  
pp. 321-324 ◽  
Author(s):  
Hirofumi Matsuhata ◽  
Hirotaka Yamaguchi ◽  
Ichiro Nagai ◽  
Toshiyuki Ohno ◽  
Ryouji Kosugi ◽  
...  
Keyword(s):  
Basal Plane ◽  
Grazing Incidence ◽  
Incidence Geometry ◽  
Burgers Vector ◽  
X Ray ◽  
Substrate Wafer ◽  
G 11 ◽  
Edge Dislocations ◽  
Grazing Incidence Geometry ◽  
Monochromatic Synchrotron

Dislocations in a substrate wafer of 4H-SiC with an epi-layer were observed using technique of monochromatic synchrotron X-ray topography in a grazing incidence geometry. Six different Burgers vectors of basal plane dislocations and threading edge dislocations were identified by changing the Bragg reflections, and by analysis of images of dislocation. We identify some relations of the Burgers vector and the dislocation contrast observed for g=11 2 8. Some of these relationships are discussed in this report.

Synchrotron X-Ray Topography Study on the Relationship between Local Basal Plane Bending and Basal Plane Dislocations in PVT-Grown 4H-SiC Substrate Wafers

2020 ◽  
Vol 1004 ◽  
pp. 393-400
Author(s):  
Tuerxun Ailihumaer ◽  
Hongyu Peng ◽  
Balaji Raghothamachar ◽  
Michael Dudley ◽  
Gilyong Chung ◽  
...  
Keyword(s):  
Basal Plane ◽  
Local Strain ◽  
Grazing Incidence ◽  
Peak Shift ◽  
Linear Mapping ◽  
Incidence Geometry ◽  
Convex Shape ◽  
X Ray ◽  
Black And White ◽  
Plane Bending

Synchrotron monochromatic beam X-ray topography (SMBXT) in grazing incidence geometry shows black and white contrast for basal plane dislocations (BPDs) with Burgers vectors of opposite signs as demonstrated using ray tracing simulations. The inhomogeneous distribution of these dislocations is associated with the concave/convex shape of the basal plane. Therefore, the distribution of these two BPD types were examined for several 6-inch diameter 4H-SiC substrates and the net BPD density distribution was used for evaluating the nature and magnitude of basal plane bending in these wafers. Results show different bending behaviors along the two radial directions - [110] and [100] directions, indicating the existence of non-isotropic bending. Linear mapping of the peak shift of the 0008 reflection along the two directions was carried out using HRXRD to correlate with the results from the SMBXT measurements. Basal-plane-tilt angle calculated using the net BPD density derived from SMBXT shows a good correlation with those obtained from HRXRD measurements, which further confirmed that bending in basal plane is caused by the non-uniform distribution of BPDs. Regions of severe bending were found to be associated with both large tilt angles (95% black contrast BPDs to 5% white contrast BPDs) and abrupt changes in a and c lattice parameters i.e. local strain.

Influence of High Temperature Annealing on Microstructure Evolution of Ni-24Fe-14Cr-8Mo Superalloy

2021 ◽  
Vol 904 ◽  
pp. 117-123
Author(s):  
Yi Cui ◽  
Yun Fei Zhang ◽  
Yan Guang Han ◽  
Da Lv
Keyword(s):  
High Temperature ◽  
Microstructure Evolution ◽  
Testing Machine ◽  
Aging Treatment ◽  
Growth Patterns ◽  
High Temperature Annealing ◽  
Rockwell Hardness ◽  
Hardness Testing ◽  
X Ray Diffraction ◽  
X Ray

The effect of high temperature annealing on microstructure evolution of Ni-24Fe-14Cr-8Mo alloy was investigated through Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Rockwell Hardness Testing Machine. Three kinds of grain growth patterns were found at different annealing temperatures due to carbides precipitation and dissolution. After a combination of high temperature annealing and aging treatment, the hardness versus time curves performed a parabolic pattern. The highest hardness was achieved under 1070°C/60 minutes treatment, and the desirable annealing time should be 60 minutes to 90 minutes.

Four-inch high quality crack-free AlN layer grown on a high-temperature annealed AlN template by MOCVD

2021 ◽  
Vol 42 (12) ◽  
pp. 122804
Author(s):  
Shangfeng Liu ◽  
Ye Yuan ◽  
Shanshan Sheng ◽  
Tao Wang ◽  
Jin Zhang ◽  
...  
Keyword(s):  
High Temperature ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Flat Surface ◽  
Epitaxial Lateral Overgrowth ◽  
High Temperature Annealing ◽  
High Quality ◽  
High Crystalline Quality ◽  
X Ray ◽  
Lateral Overgrowth

Abstract In this work, based on physical vapor deposition and high-temperature annealing (HTA), the 4-inch crack-free high-quality AlN template is initialized. Benefiting from the crystal recrystallization during the HTA process, the FWHMs of X-ray rocking curves for (002) and (102) planes are encouragingly decreased to 62 and 282 arcsec, respectively. On such an AlN template, an ultra-thin AlN with a thickness of ~700 nm grown by MOCVD shows good quality, thus avoiding the epitaxial lateral overgrowth (ELOG) process in which 3–4 μm AlN is essential to obtain the flat surface and high crystalline quality. The 4-inch scaled wafer provides an avenue to match UVC-LED with the fabrication process of traditional GaN-based blue LED, therefore significantly improving yields and decreasing cost.

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