Numerical Simulation of Liquid Phase Diffusion Growth of SiGe Single Crystals under Zero Gravity

• Published in: Fluid dynamics & materials processing Vol. 9; no. 4; pp. 331 - 351
• Main Authors: Sekhon, M, Armour, N, Dost, S
• Format: Journal Article
• Language: English
• Published: Duluth Tech Science Press 01.01.2013
• Subjects: Chemical precipitation; Computer simulation; Crystal growth; Crystals; Diffusion; Diffusion rate; Enthalpy; Free convection; Gravitation; Gravity jitter; Initial conditions; International Space Station; Liquid phases; Mathematical models; Melting; Numerical prediction; Silicon; Silicon germanides; Simulation; Single crystals; Solidification; Spaceborne experiments; Vibration; Weightlessness
• ISSN: 1555-256X; 1555-2578
• DOI: 10.3970/fdmp.2013.009.331

Liquid Phase Diffusion (LPD) growth of SixGe1-x single crystals has been numerically simulated under zero gravity. The objective was to examine growth rate and silicon concentration distribution in the LPD grown crystals under diffusion dominated mass transport prior to the planned LPD space experiments on the International Space Station (ISS). Since we are interested in predicting growth rate and crystal composition, the gravitational fluctuation of the ISS (g-jitter) was neglected and the gravity level was taken as zero for simplicity. The present simulation results agree qualitatively with the radial and axial silicon distributions in the grown crystals of the Earth-bound experiments, and also with those previously predicted numerically. The computed total growth rate also agrees quantitatively with that of the experiment. Such a small discrepancy is expected since the contribution of natural convection in the melt was not included in the present simulation. A well-design LPD space experiment may shed light on this prediction.