doi:10.1016/j.jcrysgro.2004.05.085 
Copyright © 2004 Elsevier B.V. All rights reserved.
Numerical modelling for convection in growth/dissolution of solid solution CdXHg1−XTe by liquid-phase epitaxy
I. A. Denisova, O. S. Mazhorova
, 
, b, Yu. P. Popovb and N. A. Smirnovaa
a State Institute for Rare Metals, 5, B.Tolmachevskiy, Moscow 109017, Russia
b Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, 4 Miusskaya pl, Moscow 125047, Russia
Received 22 July 2003;
accepted 7 May 2004
Communicated by G. Müller
Available online 2 July 2004.
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Abstract
The paper presents a numerical study of natural convection in the liquid-phase epitaxy (LPE) of ternary compounds. 2D computer simulation of LPE techniques that make use of dissolution of the substrate prior to growth is carried out. The computed data allow to specify the region of experimental conditions, such as melt thickness, cooling rate, initial superheating, etc., that are favorable for obtaining epitaxial heterostructures with a uniform thickness and a homogeneous composition distribution across the substrate area.
Author Keywords: A1. Computer simulation; A3. Liquid-phase epitaxy; B3. Semiconducting ternary compounds
Fig. 1. (a) Flow pattern, concentration field for Cd and dissolution rate at t=2 min. H=0.2 cm, L=2.5 cm. Initial solution composition is in equilibrium with solid phase CdX0Hg1−X0Te, X0=0.187 at T=782 K. CdTe substrate is brought into contact with the solution at T0=788 K, i.e. the amount of superheating is ΔT=6 K. Contact of the substrate with liquid phase is followed immediately by cooling at the cooling rate α=1.0 K/min. (The concentration patterns for Hg are similar to Cd, since in simulation DCd=DHg.) (b) Flow pattern, concentration field at t=4 min and interface of dissolved substrate surface at t=2 min and grown layer at t=4 min.
Fig. 2. Nonuniformity of dissolution interface against the liquid-phase thickness for different initial superheating ΔT , where dmax, dmin are the maximum and the minimum of the dissolution depth along a substrate.
Fig. 3. Nonuniformity of the dissolution interface against the cooling rate for different liquid-phase thickness, initial superheating is ΔT=6 K.
Fig. 4. Time history of dissolution and growth thickness in the middle of the substrate. H=0.15 cm, L=2.5 cm, initial superheating ΔT=6 K. The system is cooled at a given rate from the contact temperature T0=788 K to T1=780 K and then kept at the constant temperature T1. Initial solution composition is in equilibrium with solid phase CdX0Hg1−X0Te, X0=0.187 at T=782 K.
Fig. 5. Composition distribution in the grown layer (middle of the substrate).
Table 1. Physical parameters.
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