Structural Characterization of Lateral-grown 6H-SiC a/m-plane Seed Crystals by Hot Wall CVD Epitaxy

2014 ◽  
Vol 1693 ◽  
Author(s):  
Ouloide Yannick Goue ◽  
Balaji Raghothamachar ◽  
Michael Dudley ◽  
Andrew J. Trunek ◽  
Philip G. Neudeck ◽  
...  
Keyword(s):  
Grown Crystal ◽  
Stacking Faults ◽  
Chemical Vapor ◽  
Growth Direction ◽  
Seed Crystal ◽  
Lateral Expansion ◽  
X Ray ◽  
Seed Crystals ◽  
High Resolution Tem ◽  
Crystal Fibers

ABSTRACTThe performance of commercially available silicon carbide (SiC) power devices is limited due to inherently high density of screw dislocations (SD), which are necessary for maintaining polytype during boule growth and commercially viable growth rates. The NASA Glenn Research Center (GRC) has recently proposed a new bulk growth process based on axial fiber growth (parallel to the c-axis) followed by lateral expansion (perpendicular to the c-axis) for producing multi-faceted m-plane SiC boules that can potentially produce wafers with as few as one SD per wafer. In order to implement this novel growth technique, the lateral homoepitaxial growth expansion of a SiC fiber without introducing a significant number of additional defects is critical. Lateral expansion is being investigated by hot wall chemical vapor deposition (HWCVD) growth of 6H-SiC a/m-plane seed crystals (0.8mm x 0.5mm x 15mm) designed to replicate axially grown SiC single crystal fibers. The post-growth crystals exhibit hexagonal morphology with approximately 1500 μm (1.5 mm) of total lateral expansion. Preliminary analysis by synchrotron white beam x-ray topography (SWBXT) confirms that the growth was homoepitaxial, matching the polytype of the respective underlying region of the seed crystal. Axial and transverse sections from the as-grown crystal samples were characterized in detail by a combination of SWBXT, transmission electron microscopy (TEM) and Raman spectroscopy to map defect types and distribution. X-ray diffraction analysis indicates the seed crystal contained stacking disorders and this appears to have been reproduced in the lateral growth sections. Analysis of the relative intensity for folded transverse acoustic (FTA) and optical (FTO) modes on the Raman spectra indicate the existence of stacking faults (SFs). Further, the density of stacking faults is higher in the seed than in the grown crystal. Bundles of dislocations are observed propagating from the seed in m-axis lateral directions. Contrast extinction analysis of these dislocation lines reveals they are edge type basal plane dislocations that track the growth direction. Polytype phase transition and stacking faults were observed by high-resolution TEM (HRTEM), in agreement with SWBXT and Raman scattering.

Polytype and Crystal Quality of SiC Crystals Grown on 3C-SiC by Seeded Solution Method

2009 ◽  
Vol 615-617 ◽  
pp. 27-30 ◽  
Author(s):  
Kazuaki Seki ◽  
Ryo Tanaka ◽  
Toru Ujihara ◽  
Yoshikazu Takeda
Keyword(s):  
Growth Process ◽  
Solution Method ◽  
Grown Crystal ◽  
Stacking Faults ◽  
High Density ◽  
Seed Crystal ◽  
Solution Growth ◽  
Crystal Quality ◽  
Seed Crystals

We investigated the effects of the solution growth process on the polytype and crystal quality of the crystals grown on (111) 3C-SiC seed crystals. In spite of the use of 3C-SiC seed crystals, the polytype of the grown crystal changed from 3C-SiC to 6H-SiC, because the stacking errors easily occur due to the similarity of the (111) face of 3C-SiC and the (0001) face of 6H-SiC. Moreover, the grown 6H-SiC crystal affected the crystal quality of the seed crystal, i.e., high-density stacking faults were induced in the seed crystal after the growth process.

Crystallinity of YBa2Cu3O7−x single crystals grown by the pulling method

1996 ◽  
Vol 11 (4) ◽  
pp. 804-812 ◽  
Author(s):  
Y. Namikawa ◽  
M. Egami ◽  
S. Koyama ◽  
Y. Shiohara ◽  
H. Kutami
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Growth Direction ◽  
Annealed Sample ◽  
Seed Crystal ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Crystal Seed ◽  
Better Than

Large YBa2Cu3O7−x (Y123) single crystals (larger than 13 mm cubed) have been grown along the c-axis reproducibly by the modified pulling method. The crystallinity of Y123 single crystal was investigated by x-ray diffraction and x-ray topography. Crystals grown from an MgO single crystal seed had some low angle subgrain boundaries which tilted 0.1–0.8° from each other. These grain boundaries originated from the seed crystal, and the subgrains were extended along the growth direction from the seed crystal. Y123 single crystals with no marked subgrains in the whole area were obtained by using Y123 single subgrain crystal seeds. FWHM of the x-ray rocking curve for the crystal so produced was about 0.14°, which was much better than the spectrum consisting of several separated peaks obtained from the previous crystals. Tc onset of the annealed sample was about 93.6 K, and the transition width was about 0.9 K. The low angle subgrain boundaries did not seem to be effective pinning centers for the magnetic flux.

scholarly journals Highly Visible Photoluminescence from Ta-Doped Structures of ZnO Films Grown by HFCVD

Crystals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 395 ◽  
Author(s):  
Víctor Herrera ◽  
Tomás Díaz-Becerril ◽  
Eric Reyes-Cervantes ◽  
Godofredo García-Salgado ◽  
Reina Galeazzi ◽  
...  
Keyword(s):  
Raw Materials ◽  
Chemical Vapor ◽  
Growth Direction ◽  
Hexagonal Structure ◽  
Zno Films ◽  
Sem Images ◽  
Wurtzite Phase ◽  
Fixed Amount ◽  
X Ray ◽  
Doped Zno

Tantalum-doped ZnO structures (ZnO:Ta) were synthesized, and some of their characteristics were studied. ZnO material was deposited on silicon substrates by using a hot filament chemical vapor deposition (HFCVD) reactor. The raw materials were a pellet made of a mixture of ZnO and Ta2O5 powders, and molecular hydrogen was used as a reactant gas. The percentage of tantalum varied from 0 to 500 mg by varying the percentages of tantalum oxide in the mixture of the pellet source, by holding a fixed amount of 500 mg of ZnO in all experiments. X-ray diffractograms confirmed the presence of zinc oxide in the wurtzite phase, and metallic zinc with a hexagonal structure, and no other phase was detected. Displacements to lower angles of reflection peaks, compared with those from samples without doping, were interpreted as the inclusion of the Ta atoms in the matrix of the ZnO. This fact was confirmed by energy dispersive X-ray spectrometry (EDS), and X-ray diffraction (XRD) measurements. From scanning electron microscopy (SEM) images from undoped samples, mostly micro-sized semi-spherical structures were seen, while doped samples displayed a trend to grow as nanocrystalline rods. The presence of tantalum during the synthesis affected the growth direction. Green photoluminescence was observed by the naked eye when Ta-doped samples were illuminated by ultraviolet radiation and confirmed by photoluminescence (PL) spectra. The PL intensity on the Ta-doped ZnO increased from those undoped samples up to eight times.

Microstructure observations of silicon carbide nanorods

2000 ◽  
Vol 15 (9) ◽  
pp. 2020-2026 ◽  
Author(s):  
H. Y. Peng ◽  
X. T. Zhou ◽  
H. L. Lai ◽  
N. Wang ◽  
S. T. Lee
Keyword(s):  
Vapor Deposition ◽  
Stacking Faults ◽  
Chemical Vapor ◽  
High Resolution Electron Microscopy ◽  
Growth Direction ◽  
Planar Defects ◽  
Resolution Electron ◽  
Short Nanorods ◽  
Hot Filament ◽  
Nanorod Growth

The microstructures of β-SiC nanorods synthesized by hot-filament chemical vapor deposition were studied in detail by high-resolution electron microscopy. Two distinct types of nanorods were identified. The longer nanorods (lengths > 0.1 mm) contained globules at their tips and a relatively low density of stacking faults perpendicular to their [111] growth direction. It was also observed that SiC nanorods that grew along [100] direction contained no planar defects. Meanwhile, Ni was found to be an effective catalyst for SiC nanorod growth. The short nanorods (lengths < 50 nm), which contained no globules at their ends, can grow along [111], [100], or [112] direction. The growth of these nanorods was interpreted by a two-dimensional vapor–solid mechanism.

scholarly journals Characterization of individual stacking faults in a wurtzite GaAs nanowire by nanobeam X-ray diffraction

2017 ◽  
Vol 24 (5) ◽  
pp. 981-990 ◽  
Author(s):  
Arman Davtyan ◽  
Sebastian Lehmann ◽  
Dominik Kriegner ◽  
Reza R. Zamani ◽  
Kimberly A. Dick ◽  
...  
Keyword(s):  
Bragg Peak ◽  
Stacking Faults ◽  
Growth Direction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Patterson Function ◽  
Transmission Electron ◽  
Gaas Nanowires ◽  
Gaas Nanowire

Coherent X-ray diffraction was used to measure the type, quantity and the relative distances between stacking faults along the growth direction of two individual wurtzite GaAs nanowires grown by metalorganic vapour epitaxy. The presented approach is based on the general property of the Patterson function, which is the autocorrelation of the electron density as well as the Fourier transformation of the diffracted intensity distribution of an object. Partial Patterson functions were extracted from the diffracted intensity measured along the [000\bar{1}] direction in the vicinity of the wurtzite 00\bar{1}\bar{5} Bragg peak. The maxima of the Patterson function encode both the distances between the fault planes and the type of the fault planes with the sensitivity of a single atomic bilayer. The positions of the fault planes are deduced from the positions and shapes of the maxima of the Patterson function and they are in excellent agreement with the positions found with transmission electron microscopy of the same nanowire.

Chemical Vapor Deposited Boron Carbide: Growth by a Vapor-Liquidsolid Process

1987 ◽  
Vol 97 ◽  
Author(s):  
Ian D. R. Mackinnon ◽  
Katherine L. Smith
Keyword(s):  
Vapor Deposition ◽  
Low Temperatures ◽  
Growth Process ◽  
Stacking Faults ◽  
Chemical Vapor ◽  
Growth Direction ◽  
Chemical Vapor Deposited ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Oriented Parallel

ABSTRACTDetailed analytical electron microscope (AEM) studies of yellow whiskers produced by chemical vapor deposition (CVD)1 show that two basic types of whiskers are produced at low temperatures (between 1200°C and 1400°C) and low boron to carbon gas ratios. Both whisker types show planar microstructures such as twin planes and stacking faults oriented parallel to, or at a rhombohedral angle to, the growth direction. For both whisker types, the presence of droplet-like terminations containing both Si and Ni indicate that the growth process during CVD is via a vapor-liquid-solid (VLS) mechanism.

High Temperature Solution Growth on Free-Standing (001) 3C-SiC Epilayers

2009 ◽  
Vol 615-617 ◽  
pp. 37-40 ◽  
Author(s):  
Ryo Tanaka ◽  
Kazuaki Seki ◽  
Toru Ujihara ◽  
Yoshikazu Takeda
Keyword(s):  
Grown Crystal ◽  
Stacking Faults ◽  
Seed Crystal ◽  
Solution Growth ◽  
High Temperature Solution ◽  
Si Substrate ◽  
Free Standing ◽  
Cvd Method ◽  
Temperature Solution ◽  
Cvd Growth

Solution growth was performed using a free-standing (001) 3C-SiC epilayer as a seed crystal at a growth temperature of 1700°C. The seed crystal was prepared by a CVD method on the undulated Si substrate. 3C-SiC stably grew on the (001) seed crystal. However, dark stripes from the seed crystal to the grown crystal along {111} planes were clearly observed. The stripes were due to the high-density stacking faults extended from the stacking faults in the 3C-SiC epilayer that were induced during the CVD growth on Si substrate.

scholarly journals Surface Morphology Study of Chemical Vapor Transport of ZnO Crystals

Scanning ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Long Fan ◽  
Jia Li ◽  
Dawei Yan ◽  
Liping Peng ◽  
Tao Jiang ◽  
...  
Keyword(s):  
Grown Crystal ◽  
Chemical Vapor ◽  
Optical Microscope ◽  
Vapor Transport ◽  
Chemical Vapor Transport ◽  
X Ray Diffraction ◽  
Vapor Interface ◽  
X Ray ◽  
Thermal Etching ◽  
Scanning Electron

A chemical vapor transport (CVT) method was implemented to grow bulk ZnO crystals. X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), and optical microscope (OM) studies were carried out to characterize the surface properties of the grown crystal. The XRD result indicated the exposed solid-vapor interface of the as-grown crystal was composed of (0001) and {101-1} faces. Using SEM and OM, we observed small hexagonal pyramids and microstructures formed of crosslines on the as-grown crystal and found hexagonal thermal etching pits on the surfaces of seed crystals. The formation, evolution, and distribution mechanisms of the microstructures were investigated.

Lateral Growth Expansion of 4H/6H-SiС M-Plane Pseudo Fiber Crystals by Hot Wall CVD Epitaxy

2012 ◽  
Vol 717-720 ◽  
pp. 33-36 ◽  
Author(s):  
Andrew J. Trunek ◽  
Philip G. Neudeck ◽  
Andrew A. Woodworth ◽  
J. Anthony Powell ◽  
David J. Spry ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Lateral Growth ◽  
Lateral Expansion ◽  
X Ray ◽  
Initial Analysis ◽  
White Beam

Lateral expansion of small mixed polytype 4H/6H-SiC and 6H-SiC slivers were realized by hot wall chemical vapor deposition (HWCVD). Small slivers cut from m-oriented (11 ̅00) SiC boule slices containing regions of 4H and 6H-SiC or just single polytype 6H-SiC were exposed to HWCVD conditions using standard silane/propane chemistry for a period of up to eight hours. The slivers exhibited approximately 1500 μm (1.5 mm) of total lateral expansion. Initial analysis by synchrotron white beam x-ray topography (SWBXT) confirms, that the lateral growth was homoepitaxial, matching the polytype of the respective underlying region of the seed sliver.

Structural Transformation from TSDs to Frank-Type Stacking Faults by Giant Bunched Steps in PVT-Grown 4H-SiC Single Crystals

2016 ◽  
Vol 858 ◽  
pp. 97-100 ◽  
Author(s):  
Shinya Sato ◽  
Tatsuo Fujimoto ◽  
Hiroshi Tsuge ◽  
Masakazu Katsuno ◽  
Masashi Nakabayashi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Single Crystals ◽  
Structural Transformation ◽  
Stacking Faults ◽  
Stacking Sequence ◽  
Screw Dislocations ◽  
X Ray ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Stacking Structure

Structural transformation from threading screw dislocations (TSDs) to stacking faults (SFs) has been investigated for PVT-grown 4H-SiC single crystals using X-ray topography and transmission electron microscopy (TEM). The transformation of TSDs is induced by the structural interference with bunched surface macrosteps over 100 nm in height. The stacking sequence of a SF was determined to be (433) in Zadanov's notation by using high-resolution TEM. Our detailed analyses revealed that the (433) stacking structure can be constructed by a combination of five faults including both four Frank type faults and one Shockley type fault.

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