scholarly journals Influences of Powder Source Porosity on Mass Transport during AlN Crystal Growth Using Physical Vapor Transport Method

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1436
Author(s):  
Danyang Fu ◽  
Qikun Wang ◽  
Gang Zhang ◽  
Zhe Li ◽  
Jiali Huang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Mass Transport ◽  
Growth Conditions ◽  
Vapor Transport ◽  
Growth Chamber ◽  
Physical Vapor Transport ◽  
Rate Variation ◽  
Deposition Surface ◽  
Mass Transport Process

We developed a two-dimensional (2D) transport model to investigate mass transport during bulk AlN crystal growth via the physical vapor transport (PVT) process using the finite element method (FEM), taking the powder source porosity, buoyancy, and vapor diffusion into account. The porosity effects of the powder source on mass transport under various growth conditions were investigated in detail. The simulation results show that the porosity of the powder source significantly affects the mass transport process during AlN sublimation growth. When the porosity of the powder source decreases, the growth rate becomes more uniform along the seed deposition surface, although the sublimation rate and crystal growth rate decrease, which can be attributed to the reduced specific surface area of the powder source and the reduced flow rate of Al vapor in the powder source. A flat growth interface can be achieved at a porosity of 0.2 under our specific growth conditions, which in turn facilitate the growth of high-quality AlN crystals and better yield. The decomposition of the powder source and the transport of Al vapor in the growth chamber can be suppressed by increasing the pressure. In addition, the AlN growth rate variation along the deposition surface can be attributed to the Al vapor pressure gradient caused by the temperature difference in the growth chamber.

Influence of crucible shape on mass transport in AlN crystal growth by physical vapor transport process

2019 ◽  
Vol 515 ◽  
pp. 21-25 ◽  
Author(s):  
Qikun Wang ◽  
Jiali Huang ◽  
Danyang Fu ◽  
Guangdong He ◽  
Dan Lei ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Mass Transport ◽  
Transport Process ◽  
Vapor Transport ◽  
Physical Vapor Transport

A Technique For Rapid Thick Film Sic Epitaxial Growth

1997 ◽  
Vol 483 ◽  
Author(s):  
I. Khlebnikov ◽  
T. S. Sudarshan ◽  
V. Madangarli ◽  
M. A. Capano
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
High Growth ◽  
High Growth Rate ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Structural Quality ◽  
Epitaxial Layers ◽  
Rocking Curve ◽  
X Ray

AbstractIn this paper we demonstrate the growth of thick SiC epitaxial layers (≥100 μm) of good structural quality at a high growth rate (>100 μm/hr) by controlling the vapor dynamics during conventional physical vapor transport (PVT) process. We propose that our PVT technique be used to ‘repair’ or ‘heal’ commercially available substrates dominated by micropipes, by ‘filling up’ the micropipes through crystal growth inside the micropipe. Extensive experiments performed on thick SiC epitaxial layers grown on Lely substrates indicate that the thick epitaxial layers are of single polytype of high structural quality, with a single peak X-ray rocking curve of less than 12 arcsecs FWHM.

Gravity-Driven Convection Studies in Compound Semiconductor Crystal Growth by Physical Vapor Transport

1981 ◽  
Vol 9 ◽  
Author(s):  
John A. Zoutendyk ◽  
Wesley M. Akutagawa
Keyword(s):  
Crystal Growth ◽  
Mass Transport ◽  
Compound Semiconductors ◽  
Compound Semiconductor ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Semiconductor Crystal ◽  
Transport Behavior ◽  
Gravity Driven

ABSTRACTGravity-driven convection can alter the diffusive-advective mass transport behavior in the growth of crystals by physical vapor transport. Specially designed and constructed transparent furnaces are being used in our laboratory to study the effects of gravity in crystal growth of the compound semiconductors PbTe and CdTe.

Modified Physical Vapor Transport Growth of SiC - Control of Gas Phase Composition for Improved Process Conditions

2005 ◽  
Vol 483-485 ◽  
pp. 25-30 ◽  
Author(s):  
Peter J. Wellmann ◽  
Thomas L. Straubinger ◽  
Patrick Desperrier ◽  
Ralf Müller ◽  
Ulrike Künecke ◽  
...  
Keyword(s):  
Temperature Field ◽  
Phase Composition ◽  
Gas Phase ◽  
Growth Conditions ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Process Conditions ◽  
Growth Technique ◽  
Experimental Implementation ◽  
P Type

We review the development of a modified physical vapor transport (M-PVT) growth technique for the preparation of SiC single crystals which makes use of an additional gas pipe into the growth cell. While the gas phase composition is basically fixed in conventional physical vapor transport (PVT) growth by crucible design and temperature field, the gas inlet of the MPVT configuration allows the direct tuning of the gas phase composition for improved growth conditions. The phrase "additional" means that only small amounts of extra gases are supplied in order to fine-tune the gas phase composition. We discuss the experimental implementation of the extra gas pipe and present numerical simulations of temperature field and mass transport in the new growth configuration. The potential of the growth technique will be outlined by showing the improvements achieved for p-type doping of 4H-SiC with aluminum, i.e. [Al]=9⋅1019cm-3 and ρ<0.2Ωcm, and n-type doping of SiC with phosphorous, i.e. [P]=7.8⋅1017cm-3.

scholarly journals Macrodefects in Cubic Silicon Carbide Crystals

2010 ◽  
Vol 645-648 ◽  
pp. 375-378 ◽  
Author(s):  
Valdas Jokubavicius ◽  
Justinas Palisaitis ◽  
Remigijus Vasiliauskas ◽  
Rositza Yakimova ◽  
Mikael Syväjärvi
Keyword(s):  
Growth Rate ◽  
Silicon Carbide ◽  
Crystal Growth ◽  
High Temperature ◽  
Temperature Gradient ◽  
Early Stage ◽  
Growth Conditions ◽  
Temperature Ramp ◽  
Cubic Silicon Carbide ◽  
Sublimation Growth

Different sublimation growth conditions of 3C-SiC approaching a bulk process have been investigated with the focus on appearance of macrodefects. The growth rate of 3C-SiC crystals grown on 6H-SiC varied from 380 to 460 μm/h with the thickness of the crystals from 190 to 230 μm, respectively. The formation of macrodefects with void character was revealed at the early stage of 3C-SiC crystal growth. The highest concentration of macrodefects appears in the vicinity of the domain in samples grown under high temperature gradient and fastest temperature ramp up. The formation of macrodefects was related to carbon deficiency which appear due to high Si/C ratio which is used to enable formation of the 3C-SiC polytype.

Optimum growth conditions for the epitaxy of GaAs on Ge by close-spaced vapor transport

1994 ◽  
Vol 72 (5-6) ◽  
pp. 225-232 ◽  
Author(s):  
G. Lalande ◽  
N. Guelton ◽  
D. Cossement ◽  
R. G. Saint-Jacques ◽  
J. P. Dodelet
Keyword(s):  
Growth Rate ◽  
Solar Cells ◽  
Water Vapor ◽  
Substrate Temperature ◽  
Growth Conditions ◽  
Vapor Transport ◽  
Temperature Evolution ◽  
Threading Dislocations ◽  
Optimum Growth ◽  
Antiphase Boundaries

GaAs epitaxial layers are grown by close-spaced vapor transport (CSVT) on (100)Ge substrates and (100)Ge substrates misoriented 1.5° and 3° toward (011). Water vapor is used as the transport agent. When the temperatures of the GaAs source (T1) and of the Ge substrate (T2) are 800 and 750 °C, respectively, the growth rate is about 3 μm h−1. When an optimum source–substrate temperature evolution is followed, it is possible to grow specular layers of GaAs/Ge that contain only a small number (< 105 cm−2) of threading dislocations. All antiphase boundaries (APBs) annihilate close to the interface (from about 230 nm for (100)Ge substrates to about 65 nm for vicinal (3° off) (100)Ge substrates). The GaAs growth occurs via the coalescence of 3D nuclei that are formed on an arsenic prelayer n-type GaAs layers are always obtained. By encapsulating the Ge substrate, it is possible to drastically decrease the autodoping resulting from the transport of Ge by water vapor in the same growth conditions as those prevailing for GaAs. After encapsulation, uncompensated doping densities ND – NA in the order of 5 × 1016 cm−3 are easily obtained for GaAs/Ge films grown from undoped semi-insulating GaAs sources. These GaAs/Ge layers can be used as bases for solar cells.

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