Micro-pulling-down

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.

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:


 * 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