scholarly journals The Micro Bubble Effect in the Seed Adhesion on the Crystal Quality of 6H-SiC grown by a Physical Vapor Transport (PVT) Process

2008 ◽  
Vol 21 (3) ◽  
pp. 222-226
Keyword(s):  
Vapor Transport ◽  
Crystal Quality ◽  
Physical Vapor Transport ◽  
Micro Bubble

High Quality SiC Crystals Grown by the Physical Vapor Transport Method with a New Crucible Design

2006 ◽  
Vol 527-529 ◽  
pp. 83-86 ◽  
Author(s):  
Kap Ryeol Ku ◽  
Jung Kyu Kim ◽  
Jung Doo Seo ◽  
Ju Young Lee ◽  
Myung Ok Kyun ◽  
...  
Keyword(s):  
Doping Concentration ◽  
Concentration Level ◽  
Vapor Transport ◽  
Crystal Quality ◽  
Physical Vapor Transport ◽  
Guide Tube ◽  
P Type ◽  
Transport Method ◽  
Vapor Transport Method

SiC single crystal ingots grown by sublimation physical vapor transport (PVT) technique were prepared and then the SiC crystal quality with varying crucible design employing a guide tube and tantalum foil was systematically investigated. The growth rate of 2-inch SiC crystal grown by these crucible designs was about 0.3 mm/hr. The n-type and p-type 2”-SiC single crystals exhibiting the polytype of 6H-SiC were successfully fabricated. The doping concentration level of below ~1017/cm3 was extracted from the absorption spectrum and Hall measurement. The densities of micropipes and inclusions in SiC crystal boules grown using the graphite/Ta foil double layer guide tube were significantly decreased. Finally we improved crystal quality through the introduction of new crucible design.

SiC Single Crystal Growth on Dual Seed with Different Surface Properties

2013 ◽  
Vol 740-742 ◽  
pp. 11-14
Author(s):  
Sang Il Lee ◽  
Jung Young Jung ◽  
Mi Seon Park ◽  
Hee Tae Lee ◽  
Doe Hyung Lee ◽  
...  
Keyword(s):  
Surface Properties ◽  
Growth Period ◽  
Single Crystal Growth ◽  
Seed Crystal ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Mean Square ◽  
Transport Technique ◽  
Better Than

SiC crystal ingots were grown on 6H-SiC dual-seed crystal with different surface properties by a PVT (Physical Vapor Transport) technique. And then SiC crystal wafers sliced from the SiC ingots were systematically investigated in order to find out the dependence of surface properties for seed on the polytype formation. While n-type SiC crystals exhibiting the 4H polytype were grown on seed crystal having high root-mean-square (rms) value, 6H-SiC crystals were grown on seed having lower rms value. However, 6H polytype was maintained on on-axis and off-axis seeds during the entire growth period. The crystal quality of 6H-SiC single crystals grown on on-axis seed were revealed to be slightly better than that of 6H-SiC crystal grown on off-axis seed.

scholarly journals X-ray characterization of physical-vapor-transport-grown bulk AlN single crystals

2020 ◽  
Vol 53 (4) ◽  
pp. 1080-1086
Author(s):  
Thomas Wicht ◽  
Stephan Müller ◽  
Roland Weingärtner ◽  
Boris Epelbaum ◽  
Sven Besendörfer ◽  
...  
Keyword(s):  
Growth Conditions ◽  
Vapor Transport ◽  
Crystal Quality ◽  
Growth Mode ◽  
Physical Vapor Transport ◽  
Lateral Growth ◽  
Thermomechanical Stress ◽  
X Ray ◽  
Outer Periphery ◽  
Homogeneous Crystal

AlN slices from bulk crystals grown under low thermomechanical stress conditions via the physical vapor transport (PVT) method were analyzed by X-ray methods to study the influence of the growth mode on the crystal quality. Defect types and densities were analyzed along axial [0001] as well as lateral growth directions. X-ray diffraction (0110) rocking-curve mappings of representative wafer cuts reveal a low mean FWHM of 13.4 arcsec, indicating the generally high crystal quality. The total dislocation density of 2 × 103 cm−2 as determined by X-ray topography is low and dislocations are largely threading edge dislocations of b = 1/3〈1120〉 type. The absence of basal plane dislocations in homogeneous crystal regions void of macroscopic defects can be linked to the low-stress growth conditions. Under the investigated growth conditions this high crystal quality can be maintained both along the axial [0001] direction and within lateral growth directions. Exceptions to this are some locally confined, misoriented grains and defect clusters, most of which are directly inherited from the seed or are formed due to the employed seed fixation technique on the outer periphery of the crystals. Seed-shaping experiments indicate no apparent kinetic limitations for an enhanced lateral expansion rate and the resulting crystal quality, specifically with regard to the growth mode on a-face facets.

Growth of Large Diameter SiC Crystals by Advanced Physical Vapor Transport

2005 ◽  
Vol 483-485 ◽  
pp. 9-12 ◽  
Author(s):  
Thomas Anderson ◽  
Donovan L. Barrett ◽  
J. Chen ◽  
Ejiro Emorhokpor ◽  
A. Gupta ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Electrical Properties ◽  
Low Temperature ◽  
Nitrogen Doping ◽  
Large Diameter ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Insulating Properties ◽  
Low Temperature Photoluminescence

Semi-insulating 6H SiC substrates, 2”, 3” and 100mm in diameter, and n+ 4H SiC substrates, 2” and 3” in diameter, are grown at II-VI using the Advanced Physical Vapor Transport (APVT) technique [1]. The process utilizes high-purity SiC source and employs special measures aimed at the reduction of background contamination. Semi-insulating properties are achieved by precise vanadium compensation, which yields substrates with stable and uniform electrical resistivity reaching ~ 1011 Ω-cm and higher. Conductive n+ 4H SiC crystals with the spatially uniform resistivity of 0.02 W-cm are grown using nitrogen doping. Crystal quality of the substrates, their electrical properties and low temperature photoluminescence are discussed.

SiC Crystal Growth by Sublimation Method with Modification of Crucible and Insulation Felt Design

2005 ◽  
Vol 483-485 ◽  
pp. 47-50 ◽  
Author(s):  
Jung Kyu Kim ◽  
Kap Ryeol Ku ◽  
Dong Jin Kim ◽  
Sang Phil Kim ◽  
Won Jae Lee ◽  
...  
Keyword(s):  
Defect Density ◽  
Structure Design ◽  
Vapor Transport ◽  
Crystal Quality ◽  
Crystal Shape ◽  
Flat Structure ◽  
Growth System ◽  
Sublimation Method ◽  
Different Shapes

SiC crystal boules with different shapes were prepared using sublimation physical vapor transport technique (PVT) and then their crystal quality was systematically investigated. The temperature distribution in the growth system and the crystal shape were controlled by modification of crucible and insulation felt design, which was successfully simulated using “Virtual Reactor” for flat structure design and concave structure design. The SiC polytype proved to be the n-type 6H-SiC from the typical absorption spectrum of SiC crystal. The defect density of SiC crystal boules with concave structure was slightly lower than that of flat structure and the crystal quality of SiC crystal boules with both flat structure and concave structure was significantly improved as the SiC crystal grows during the PVT methods.

Initial Stage Modification for 6H-SiC Single Crystal Grown by the Physical Vapor Transport (PVT) Method

2009 ◽  
Vol 615-617 ◽  
pp. 7-10 ◽  
Author(s):  
Jung Woo Choi ◽  
Chang Hyun Son ◽  
Jong Mun Choi ◽  
Gi Sub Lee ◽  
Won Jae Lee ◽  
...  
Keyword(s):  
Single Crystal ◽  
Defect Formation ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Growth Step ◽  
Initial Stage ◽  
Low Rate ◽  
Main Growth

Two SiC single crystal ingots were prepared using sublimation PVT techniques through the different process procedure and then their crystal quality was systematically compared, because the present research was focused to improve the quality of SiC crystal by modifying the initial stage of the PVT growth. Before the main growth step for growing SiC bulk crystal, initial stage period where growth rate was kept to relatively low rate of <10μm/h was introduced to conventional process procedure. N-type 2”-SiC single crystals exhibiting the polytype of 6H-SiC was successfully fabricated. As compared to the characteristics of SiC crystal grown using the conventional schedule, the quality of SiC crystal grown with modifying the initial stage was significantly improved, exhibiting decrease of defect formation such as micropipe and polytype formation.

scholarly journals The Physical Vapor Transport Method for Bulk AlN Crystal Growth

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1562 ◽  
Author(s):  
Wen-Hao Chen ◽  
Zuo-Yan Qin ◽  
Xu-Yong Tian ◽  
Xu-Hui Zhong ◽  
Zhen-Hua Sun ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Temperature Gradient ◽  
Single Crystals ◽  
Low Cost ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Inverse Temperature ◽  
Seeded Growth ◽  
Perforated Sheet

In this report, the development of physical vapor transport (PVT) methods for bulk aluminum nitride (AlN) crystal growth is reviewed. Three modified PVT methods with different features including selected growth at a conical zone, freestanding growth on a perforated sheet, and nucleation control with an inverse temperature gradient are discussed and compared in terms of the size and quality of the bulk AlN crystals they can produce as well as the process complexity. The PVT method with an inverse temperature gradient is able to significantly reduce the nucleation rate and realize the dominant growth of only one bulk AlN single crystal, and thus grow centimeter-sized bulk AlN single crystals. X-ray rocking curve (XRC) and Raman spectroscopy measurements showed a high crystalline quality of the prepared AlN crystals. The inverse temperature gradient provides an efficient and relatively low-cost method for the preparation of large-sized and high-quality AlN seed crystals used for seeded growth, devoted to the diameter enlargement and quality improvement of bulk AlN single crystals.

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