Rational Solution Growth of α-FeOOH Nanowires Driven by Screw Dislocations and Their Conversion to α-Fe2O3Nanowires

2011 ◽  
Vol 133 (22) ◽  
pp. 8408-8411 ◽  
Author(s):  
Fei Meng ◽  
Stephen A. Morin ◽  
Song Jin
Keyword(s):  
Rational Solution ◽  
Solution Growth ◽  
Screw Dislocations

Conversion Behavior of Threading Screw Dislocations on C Face with Different Surface Morphology During 4H-SiC Solution Growth

2016 ◽  
Vol 16 (11) ◽  
pp. 6436-6439 ◽  
Author(s):  
Shiyu Xiao ◽  
Shunta Harada ◽  
Kenta Murayama ◽  
Miho Tagawa ◽  
Toru Ujihara
Keyword(s):  
Surface Morphology ◽  
Solution Growth ◽  
Screw Dislocations

High-Efficiency Conversion of Threading Screw Dislocations in 4H-SiC by Solution Growth

2012 ◽  
Vol 5 (11) ◽  
pp. 115501 ◽  
Author(s):  
Yuji Yamamoto ◽  
Shunta Harada ◽  
Kazuaki Seki ◽  
Atsushi Horio ◽  
Takato Mitsuhashi ◽  
...  
Keyword(s):  
High Efficiency ◽  
Solution Growth ◽  
Screw Dislocations ◽  
Efficiency Conversion

Effect of Surface Polarity on the Conversion of Threading Dislocations in Solution Growth

2013 ◽  
Vol 740-742 ◽  
pp. 15-18 ◽  
Author(s):  
Yuji Yamamoto ◽  
S. Harada ◽  
Kazuaki Seki ◽  
Atsushi Horio ◽  
Takato Mitsuhashi ◽  
...  
Keyword(s):  
Grown Crystal ◽  
The Other ◽  
Solution Growth ◽  
Threading Dislocations ◽  
Surface Polarity ◽  
Screw Dislocations ◽  
X Ray ◽  
Almost All ◽  
Edge Dislocations ◽  
Effect Of Surface

We investigated the dislocation behaviors during the solution growth on Si-face and C-face off-axis 4H-SiC seed crystals by using synchrotron X-ray topography. On Si-face, almost all threading screw dislocations (TSDs) and threading edge dislocations (TEDs) are converted into Frank-type defects and basal plane dislocations (BPDs), respectively. On the other hand, on C-face, TSDs were hardly converted. Some of TEDs were converted to BPDs and BPD-TED reconversion was often occurred. Therefore, to reduce density of threading dislocations in the grown crystal, it is better to use Si-face off-axis seed crystal.

SiC Solution Growth on Si Face with Extremely Low Density of Threading Screw Dislocations for Suppression of Polytype Transformation

2017 ◽  
Vol 897 ◽  
pp. 24-27 ◽  
Author(s):  
Kenta Murayama ◽  
Tsukasa Hori ◽  
S. Harada ◽  
S. Xiao ◽  
M. Tagawa ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Growth Temperature ◽  
Thick Layer ◽  
High Growth ◽  
Solution Growth ◽  
Threading Dislocation ◽  
Low Density ◽  
Screw Dislocations ◽  
Threading Dislocation Density ◽  
Polytype Transformation

In order to achieve a high-quality SiC crystal in solution growth, one of the most difficult issues is to grow a thick layer on Si face avoiding polytype transformation. In this case, two-dimensional nucleation, which leads to the polytype transformation, is frequently induced because a density of threading screw dislocations acting as a source of spiral step decreases and wide terraces form by step bunching as growth proceeds. Therefore, it is very difficult to stabilize the polytype of crystals grown with extremely low density of threading screw dislocations. In this study, we tried to overcome these problems by using specially designed seed crystal and optimizing growth temperature and temperature distribution. We successfully grew thick low-threading-dislocation density SiC crystal without polytype transformation under the condition of high growth temperature and homogeneous temperature distribution.

Reduction of Threading Screw Dislocation Utilizing Defect Conversion during Solution Growth of 4H-SiC

2013 ◽  
Vol 740-742 ◽  
pp. 189-192 ◽  
Author(s):  
S. Harada ◽  
Yuji Yamamoto ◽  
Kazuaki Seki ◽  
Toru Ujihara
Keyword(s):  
Screw Dislocation ◽  
Seed Crystal ◽  
Solution Growth ◽  
Spiral Growth ◽  
High Quality ◽  
Special Shape ◽  
Screw Dislocations ◽  
Step Flow ◽  
Polytype Transformation ◽  
Step Flow Growth

Reduction of threading screw dislocation without polytype transformation from 4H-SiC was performed by the combination of step-flow growth and spiral growth. On a vicinal 4H-SiC seed crystal, threading screw dislocations are converted to Frank-type stacking faults by step-flow during solution growth. As the growth proceeds, the defects are excluded to the crystal. Thus utilizing the conversion, high quality SiC crystal growth without threading screw dislocations is expected to achieve. However, at the same time, polytype transformation is caused by the occurrence of 2D nucleation. By using the special shape of seed crystal, we successfully grew high quality 4H-SiC crystal without threading screw dislocation and polytype transformation.

Application of Defect Conversion Layer by Solution Growth for Reduction of TSDs in 4H-SiC Bulk Crystals by PVT Growth

2019 ◽  
Vol 963 ◽  
pp. 71-74 ◽  
Author(s):  
Naoyoshi Komatsu ◽  
Takeshi Mitani ◽  
Yuichiro Hayashi ◽  
Hiromasa Suo ◽  
Tomohisa Kato ◽  
...  
Keyword(s):  
Solution Growth ◽  
Bulk Crystals ◽  
Growth Technique ◽  
Screw Dislocations ◽  
Seed Crystals ◽  
Bulk Growth ◽  
Original Seed ◽  
Initial Stage ◽  
Micrometer Size ◽  
Growth Methods

We have developed the bulk growth technique to reduce threading screw dislocations (TSDs) by combining solution growth and PVT growth methods. More than 80 % of TSDs in original seed crystals were successfully converted to Frank defects on basal planes by the solution growth on 4° off C-face with Si-5at.% Ti solvent. After PVT growth on the as-grown surface of the conversion layer, TSDs in the original seed were successfully reduced. The presence of micrometer-size macrosteps in the initial stage of PVT growth is important to continue to propagate the converted Frank defects on basal planes during PVT bulk growth.

Crystallinity Evaluation of 4H-SiC Single Crystal Grown by Solution Growth Technique Using Si-Ti-C Solution

2012 ◽  
Vol 717-720 ◽  
pp. 45-48 ◽  
Author(s):  
Kazuhito Kamei ◽  
Kazuhiko Kusunoki ◽  
Nobuyuki Yashiro ◽  
Nobuhiro Okada ◽  
Koji Moriguchi ◽  
...  
Keyword(s):  
Solution Growth ◽  
Rapid Reduction ◽  
Cross Sectional ◽  
Growth Technique ◽  
Reduction Behavior ◽  
Screw Dislocations ◽  
Basal Plane Dislocation ◽  
Afm Observation ◽  
Koh Etching ◽  
Solution Growth Technique

Crystallinity of 4H-SiC bulk crystal obtained by solution growth technique was characterized mainly by KOH etching of the off-ground and serially ground specimen. Marked reduction of basal plane dislocation, threading edge and screw dislocations during the growth of on-axis crystal was confirmed. Cross-sectional TEM observation revealed the rapid reduction behavior of threading dislocations microscopically. AFM observation of as-grown morphology showed that screw dislocation dipoles is related to the reduction of threading screw dislocations and single domain formation, which is essential for establishing the high crystallinity.

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