The micro-pulling-down (μ-PD) method is a

crystal growth A crystal is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. Crystal growth is a major stage of a crystallization process, and consists of the a ...

technique based on continuous transport of the melted substance through micro-channel(s) made in a

crucible A crucible is a ceramic or metal container in which metals or other substances may be melted or subjected to very high temperatures. While crucibles were historically usually made from clay, they can be made from any material that withstands te ...

bottom. Continuous

solidification Freezing is a phase transition where a liquid turns into a solid when its temperature is lowered below its freezing point. In accordance with the internationally established definition, freezing means the solidification phase change of a liquid o ...

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 Velocity is the directional speed of an object in motion as an indication of its rate of change in position as observed from a particular frame of reference and as measured by a particular standard of time (e.g. northbound). Velocity is a ...

. Many different types of crystal are grown by this technique, including Y₃Al₅O₁₂, Si, Si-Ge, LiNbO₃, α-Al₂O₃, Y₂O₃, Sc₂O₃,

LiF Lithium fluoride is an inorganic compound with the chemical formula LiF. It is a colorless solid, that transitions to white with decreasing crystal size. Although odorless, lithium fluoride has a bitter-saline taste. Its structure is analogous to ...

, 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

References

Chemical processes Industrial processes Semiconductor growth Crystals Methods of crystal growth {{science-stub

Crystal growth routine

See also

References