Influence of growth parameters and melt convection on the solid–liquid interface during RF-floating zone crystal growth of intermetallic compounds

We present the numerical formulation of the thermal stress driven steady-state dislocation generation during the growth of shaped crystals from the melt, with Czochralski (CZ) growth of solid cylinder III–V compound semiconductors as an example. We use and compare the Haasen–Alexander model, coupling dislocation multiplication and creep strain rates, and the Jordan model, based on thermoelastic stresses. Growth parameters may be chosen so as to produce an overall approximately flat interface, leading to reduced dislocation density in the majority of the crystal's cross section. Calculation of final dislocation density requires the initial dislocation density and all stress components along the solid-liquid interface, microstructural features which depend on the physical processes leading to solidification. The final dislocation density is not sensitive to the initial dislocation density along the solid-liquid interface, but strongly depends on the interface stress. Significant stress relaxation at the interface is required to produce experimentally observed “W” shaped dislocation patterns. Crystal growth direction and crystalline anisotropy couple elastic (lattice) and plastic (slip systems) crystalline anisotropy.

Download Full-text

Numerical Analysis of Difficulties of Growing Large-Size Bulk β-Ga2O3 Single Crystals with the Czochralski Method

Crystals ◽

10.3390/cryst11010025 ◽

2020 ◽

Vol 11 (1) ◽

pp. 25

Author(s):

Xia Tang ◽

Botao Liu ◽

Yue Yu ◽

Sheng Liu ◽

Bing Gao

Keyword(s):

Crystal Growth ◽

Single Crystals ◽

Czochralski Method ◽

Liquid Interface ◽

Spiral Growth ◽

Growth Time ◽

Large Size ◽

Crystal Diameter ◽

Solid Liquid Interface ◽

Solid Liquid

The difficulties in growing large-size bulk β-Ga2O3 single crystals with the Czochralski method were numerically analyzed. The flow and temperature fields for crystals that were four and six inches in diameter were studied. When the crystal diameter is large and the crucible space becomes small, the flow field near the crystal edge becomes poorly controlled, which results in an unreasonable temperature field, which makes the interface velocity very sensitive to the phase boundary shape. The effect of seed rotation with increasing crystal diameter was also studied. With the increase in crystal diameter, the effect of seed rotation causes more uneven temperature distribution. The difficulty of growing large-size bulk β-Ga2O3 single crystals with the Czochralski method is caused by spiral growth. By using dynamic mesh technology to update the crystal growth interface, the calculation results show that the solid–liquid interface of the four-inch crystal is slightly convex and the center is slightly concave. With the increase of crystal growth time, the symmetry of cylindrical crystal will be broken, which will lead to spiral growth. The numerical results of the six-inch crystal show that the whole solid–liquid interface is concave and unstable, which is not conducive to crystal growth.

Download Full-text

Solidification parameters of the solid-liquid interface in crystal growth in response to vibration

Journal of Materials Science ◽

10.1007/bf00355960 ◽

1994 ◽

Vol 29 (15) ◽

pp. 3997-4000 ◽

Cited By ~ 12

Author(s):

Wang Fengquan ◽

Chen Shiyu ◽

He Deping ◽

Wei Bingbo ◽

Shu Guangji

Keyword(s):

Crystal Growth ◽

Liquid Interface ◽

Solidification Parameters ◽

Solid Liquid Interface ◽

Solid Liquid

Download Full-text

Crystal Growth Of A Decagonal AI-Co-Ni Quasicrystal

MRS Proceedings ◽

10.1557/proc-553-37 ◽

1998 ◽

Vol 553 ◽

Author(s):

J.Q. Guo ◽

T. J. Sato ◽

T. Kimura ◽

T. Hirano ◽

A. P. Tsai

Keyword(s):

Liquid Interface ◽

Floating Zone ◽

Solute Redistribution ◽

Zone Method ◽

Decagonal Quasicrystal ◽

X Ray ◽

State Growth ◽

Solid Liquid Interface ◽

Solid Liquid ◽

Very High

AbstractWe have grown a decagonal single quasicrystal with a size of centimeter order in an A172Co16Ni12 alloy by floating zone method at a growth rate of 0.5 mm/h. The single decagonal quasicrystal has been inspected by Laue X-ray as well as neutron diffraction, revealing a very high quasicrystalline quality. By quenching the liquid during growth, a flat solid-liquid interface has been directly observed. There exists solute redistribution at the growing solid-liquid interface. At steady state growth Al is enriched and Co, Ni are depleted in front of solid-liquid interface. Solute partition ratios of Al, Co and Ni were determined to be about 0.91, 1.57 and 1.08, respectively.

Download Full-text