Effect of Crucible Conductivity on Large Diameter, Low Gravity, Bridgman Crystal Growth

1999 ◽  
Author(s):  
Vivek Sahai ◽  
John W. Williamson
Keyword(s):  
Crystal Growth ◽  
Large Diameter ◽  
Solute Segregation ◽  
Quasi Steady State ◽  
Governing Equations ◽  
Low Gravity ◽  
Growth System ◽  
Crystal Diameter ◽  
Bridgman Crystal Growth ◽  
Ampoule Wall

Abstract This study examines the effect of crucible conductivity in minimizing convection and solute segregation in a Bridgman crystal growth system. Crystal diameter to length ratios from 0.5 to 2.5 are considered. A quasi-steady state numerical method is used to model the directional solidification of gallium doped germanium. The coupled governing equations for the melt, solidified crystal, and the ampoule wall are solved subject to appropriate boundary and interface conditions to determine the velocity, temperature, and concentration distributions. Results are presented at reduced gravity and include the effects of reducing the dimensionless ampoule conductivity from 0.67 to 0.05.

Effect of Crucible Conductivity on Large Diameter, Low Gravity, Bridgman Crystal Growth

1999 ◽  
Author(s):  
Vivek Sahai ◽  
John W. Williamson
Keyword(s):  
Crystal Growth ◽  
Large Diameter ◽  
Solute Segregation ◽  
Quasi Steady State ◽  
Governing Equations ◽  
Low Gravity ◽  
Growth System ◽  
Crystal Diameter ◽  
Bridgman Crystal Growth ◽  
Ampoule Wall

Abstract This study examines the effect of crucible conductivity in minimizing convection and solute segregation in a Bridgman crystal growth system. Crystal diameter to length ratios from 0.5 to 2.5 are considered. A quasi-steady state numerical method is used to model the directional solidification of gallium doped germanium. The coupled governing equations for the melt, solidified crystal, and the ampoule wall are solved subject to appropriate boundary and interface conditions to determine the velocity, temperature, and concentration distributions. Results are presented at reduced gravity and include the effects of reducing the dimensionless ampoule conductivity from 0.67 to 0.05.

Thermal and Solute Transportation Effects during Bridgman Crystal Growth of II-VI Compounds

2005 ◽  
Vol 475-479 ◽  
pp. 1657-1662 ◽  
Author(s):  
Wan Qi Jie
Keyword(s):  
Crystal Growth ◽  
Growth Process ◽  
Stacking Faults ◽  
Experimental Methods ◽  
Solute Segregation ◽  
Interface Morphology ◽  
Growth Interface ◽  
Bulk Crystal Growth ◽  
Bridgman Crystal Growth ◽  
As Effects

The bulk crystal growth of II-VI compounds, such as HgCdTe, CdZnTe etc., is usually carried out by Bridgman and modified Bridgman methods. Optimizing the growth process relies mainly on the understanding of the fundamental problems of solute and thermal transportation principles, which determines the composition segregations and other defects, including point defects, dislocations, precipitates, stacking faults, etc. In the last few years, the present author studied the coupling effects of the convection, thermal and solute transportation phenomena during the growth processes through both theoretical modeling and experimental methods. Several important phenomena, such as effects of ACRT forced convection on the thermal and solute field and the growth interface morphology, the shift of the growth interface due to the solute redistributions, solute segregation behaviors during the growth process, etc, are discussed. Based on these researches, technologies for growing high quality CdZnTe and other II-VI compounds have been developed.

The Study on Growth Interface of Floating Zone Silicon Crystal

2014 ◽  
Vol 633-634 ◽  
pp. 284-287
Author(s):  
Yan Jun Wang ◽  
Liu Qiao ◽  
Xue Nan Zhang ◽  
Li Li Wu ◽  
Shu Liang Gao ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Silicon Crystal ◽  
Large Diameter ◽  
Floating Zone ◽  
Growth Interface ◽  
Instability Problem ◽  
Crystal Diameter ◽  
Cooling Mechanism ◽  
Interface Curvature ◽  
Interface Inversion

The shape and stability of growth interface have significant influence on the floating zone (for short FZ) silicon crystal. During the growth of crystal cone, growth interface reversal will happen due to the change of cooling mechanism, which makes crystal growth unstable. This impact will be more obvious for crystal with large diameter. During the growth of crystal body, with the crystal diameter increasing, the growth interface curvature and thermal stress both increase, which is easy to result in dislocation and even crack of the crystal. So this experiment mainly studied how to solve the instability problem due to interface inversion and how to reduce interface curvature. In the experiment we compared the growth interface shape of 6 inches <111> FZ silicon, at different pull speed, and find that during the growth of crystal cone, interface inversion can finish ahead with higher pull speed, and during the growth of crystal body, interface curvature decreased (interface depth≈32 mm) with lower pull speed ( υ=2.5mm/min) and higher rotate speed, to increases the chances for success of crystal growth.

CONVECTIVE INSTABILITY IN CRYSTAL GROWTH SYSTEM

2002 ◽  
Vol 12 (12) ◽  
pp. 187-221 ◽  
Author(s):  
Koichi Kakimoto ◽  
Nobuyuki Imaishi
Keyword(s):  
Crystal Growth ◽  
Convective Instability ◽  
Growth System
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