What is "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 YAlO, Si, Si-Ge, LiNbO, α-AlO, YO, ScO, LiF, CaF, BaF, etc.