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

Wang, Qikun; Huang, Jiali; Fu, Dejun; He, Ge; Lei, Dan

doi:10.1016/j.jcrysgro.2019.02.059

Cited by 16 publications

(20 citation statements)

References 32 publications

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“…A resistant heating sublimation reactor loaded with an 80 mm diameter tungsten crucible was used as the AlN crystal growth system, which was mainly composed of two resistant heaters, tungsten heat insulators, and upper and lower infrared temperature measurement systems. For configurations of the furnace, the reader is referred to [15]. During the growth process, the crucible was heated to 2200-2350 • C in a nitrogen-rich atmosphere.…”

Section: Geometry Description and Numerical Modelingmentioning

confidence: 99%

“…In this work, only two species (Al and N 2 ) in the growth chamber were considered, while impurities such as Al 2 O were neglected due to their low concentrations [10][11][12][13][14][15][16]. The powder source charged at the crucible bottom was considered a porous medium.…”

Section: Geometry Description and Numerical Modelingmentioning

confidence: 99%

“…where ε is the porosity of the powder source, u is the velocity field, ρ f is the density of the gas mixture, α is the thermal expansion, T is the temperature of the fluid, g is the gravity vector, p is the system pressure, µ is the viscosity coefficient, and C i is the molar concentration of species i. D is the diffusion coefficient between species i, which was obtained from [15]. S denotes the rate of mass transfer of the gas phase from the gas-solid interface to the atmospheric chamber due to the sublimation reaction, which was obtained from [10].…”

Section: Geometry Description and Numerical Modelingmentioning

confidence: 99%

“…Gao et al [14] analyzed the influence of growth parameters on the growth rate using a mass transport model. Wang et al [15] developed a mass transport model to study the rate limiting step in the crystal growth process, and the results showed the relationship between the Al partial pressure gradient and growth rate under different thermal fields. Fu et al [16] established mass transfer models considering three-phase (Al/N/Al 2 O) Stefan flow and investigated the influences of growth parameters on oxygen impurity transport in the AlN growth chamber.…”

Section: Introductionmentioning

confidence: 99%

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

Wang²,

Zhang

et al. 2021

Crystals

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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.

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Section: Geometry Description and Numerical Modelingmentioning

confidence: 99%

Section: Geometry Description and Numerical Modelingmentioning

confidence: 99%

Section: Geometry Description and Numerical Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Wang²,

Zhang

et al. 2021

Crystals

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“…AlN in the bulk form is necessary to obtain the best performance of optical and electronic devices because of its significantly low threading dislocation density compared with AlN films grown on hetero-substrates. The AlN bulk crystal has been mostly grown through physical vapour transport (PVT) 22 , 23 and HVPE 24 , 25 . The PVT technique is essentially the only method to fabricate high-quality crystalline AlN 26 , 27 .…”

Section: Introductionmentioning

confidence: 99%

AlN formation by an Al/GaN substitution reaction

Noorprajuda

Ohtsuka

Adachi

et al. 2020

Sci Rep

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Aluminium nitride (Aln) is a promising semiconductor material for use as a substrate in high-power, high-frequency electronic and deep-ultraviolet optoelectronic devices. We study the feasibility of a novel Aln fabrication technique by using the Al/Gan substitution reaction method. the substitution method we propose here consists of an Al deposition process on a Gan substrate by a sputtering technique and heat treatment process. the substitution reaction (Al + Gan = Aln + Ga) is proceeded by heat treatment of the Al/Gan sample, which provides a low temperature, simple and easy process. C-axis-oriented Aln layers are formed at the Al/Gan interface after heat treatment of the Al/Gan samples at some conditions of 1473-1573 K for 0-3 h. A longer holding time leads to an increase in the thickness of the AlN layer. The growth rate of the AlN layer is controlled by the interdiffusion in the Aln layer. Aluminium nitride (AlN) is a promising semiconductor material for use as a substrate in high-power, highfrequency electronic and optoelectronic devices. It can be used as a substrate in AlGaN-based ultraviolet C (UV-C) optoelectronic devices owing to its wide bandgap (above 6 eV) 1 , UV transparency 2 , and close lattice constant with that of AlGaN 3. AlN can be grown in two forms: film and bulk. AlN films have been fabricated by various methods, such as metal-organic vapour-phase epitaxy (MOVPE) 4,5 , hydride vapour phase epitaxy (HVPE) 6,7 , pulsed laser deposition (PLD) 8,9 , molecular beam epitaxy (MBE) 10,11 , or sputtering 12,13 , to improve its crystalline quality, surface area, growth rate, or lower its processing temperature. Annealing techniques have been demonstrated to improve the crystalline quality of AlN films 14-16. To facilitate the further development of AlN crystal growth, several researchers have developed original and unconventional techniques. For example, the pyrolytic transportation method 17 , the liquid phase epitaxy (LPE) method using a Ga-Al binary solution 18 , Al-Sn flux growth 19 , AlN fabrication by using Al and Li 3 N solid sources 20 , and elementary-source vapour-phase epitaxy (EVPE) 21 have been demonstrated. In the pyrolytic transportation method 17 , α-Al 2 O 3 is used as an Al-source material, and it is heated at 2223 K to form Al 2 O gas in the nitrogen gas flow. The Al 2 O gas is transported to the growth zone to react with nitrogen gas at 2023 K on a sintered AlN plate for 30 h, which yields a rod-like AlN crystal (48-mm long). The advantages of this method are an economically friendly α-Al 2 O 3 source and good crystalline quality of AlN. Wu et al. 21 used metallic Al and nitrogen gas as source materials to grow an AlN crystal, which they called elementary-source vapour-phase epitaxy (EVPE). They grew the AlN with a growth rate of 18 μm/h under an optimum growth zone temperature of 1823 K. The advantages of this method are that it is conducted at a temperature lower than that of the sublimation method using no hazardous gas. Regarding the LPE methods, Adachi et al. 18 grew a 1-µm-...

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Investigation of the atomistic behavior in nanofinishing single-crystal aluminium nitride with hydroxyl radical ∙OH environment

Tang

Lin

et al. 2022

Computational Materials Science

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

Cited by 16 publications

References 32 publications

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

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

AlN formation by an Al/GaN substitution reaction

Investigation of the atomistic behavior in nanofinishing single-crystal aluminium nitride with hydroxyl radical ∙OH environment

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