Patent ID: 6875275
Filing Date: 2005-04-05
Classification: C30B,Y10T

Abstract:
1. A production apparatus for producing a crystal, said apparatus comprising: a crucible divided into a plurality of stages, each stage containing a crystal precursor material; and a heater arranged to heat said crucible, wherein each stage of said plurality of stages of said crucible has formed therein a degassing hole in a side wall portion thereof for discharging an impurity gas produced when refining the crystal precursor material by adding a scavenger thereto, and wherein a lower portion of a first stage of the plurality of stages is positioned to cover an upper edge of a wall portion of a second stage of the plurality of stages, an inner height of each stage of said plurality of stages is 10 mm to 50 mm, the degassing hole has a diameter of 1 mm to 5 mm, and a fluoride crystal is formed from the precursor material.