Micro-pulling-down explained

The micro-pulling-down (μ-PD) method is a crystal growth technique based on continuous transport of the melted substance through micro-channel(s) made in a crucible bottom. Continuous solidification of the melt is progressed on a liquid/solid interface positioned under the crucible. In a steady state, both the melt and the crystal are pulled-down with a constant (but generally different) velocity.

Many different types of crystal are grown by this technique, including Y₃Al₅O₁₂, Si, Si-Ge, LiNbO₃, α-Al₂O₃, Y₂O₃, Sc₂O₃, LiF, CaF₂, BaF₂, etc.^{[1] [2]}

Crystal growth routine

Standard routine procedure used in the growth of most of μ-PD crystals is well developed. The general stages of the growths include:^[3]

• Charging of the crucible with starting materials (mixture of powders)
• Heating of the crucible until starting materials in the crucible are completely melted
• Upward displacement of the seed until its contact with the meniscus or crucible
• Formation of the meniscus and partial melting of the seed top
• Correction of the shape of the meniscus through appropriate adjustment of crucible temperature and position of the seed crystal
• Crystal growth through pulling of the seed in downward direction
• Separation of the as grown crystal from the meniscus
• Cooling of the system (including the crystal and the crucible) to room temperature

See also

• Crystal growth
• Czochralski process
• Float-zone silicon
• Flux method
• Laser-heated pedestal growth
• Shaping processes in crystal growth
• Verneuil process
• Lithium niobate
• Sapphire
• Scandium(III) oxide
• Yttrium aluminium garnet

Notes and References

1. Book: Shaped Crystals: Growth by Micro-Pulling-Down Technique . T. Fukuda . V.I. Chani . Springer-Verlag . Berlin . 2007. 978-3-540-71294-7. Fukuda, Tsuguo. Chani, Valery I.
2. Challenge and study for developing of novel single crystalline optical materials using micro-pulling-down method . A. . Yoshikawa . Nikl, M. . Boulon, G. . Fukuda, T. . Opt. Mater. . 30 . 2007 . 1 . 6–10 . 10.1016/j.optmat.2006.10.030. 2007OptMa..30....6Y .
3. Web site: Kral . Robert . Development of micro-pulling-down method for growth of oxide and halide single crystals . Institute of Physics CAS.