| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a metal fluoride single crystal, by which the generation of fine voids can be almost suppressed even in the case that the single crystal is gradually cooled from a high temperature state for removing strains or the like in the crystal and the metal fluoride single crystal having excellent characteristics as an optical material for photolithography or the like can be efficiently obtained. SOLUTION: In the method for producing the metal fluoride single crystal, comprising growing a metal fluoride single crystal by bringing a seed crystal into contact with the surface of a melt of a metal fluoride being a raw material and pulling the seed crystal, the single crystal is grown under such a condition that the pressure in the growth furnace is regulated to reduced pressure of 0.5-70 kPa, preferably 5-50 kPa, more preferably 10-30 kPa. It is preferable that the pressure is kept by making the growth furnace into an air-tight state by shielding the furnace from the outside. COPYRIGHT: (C)2007,JPO&INPIT
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