Czochralski growth of UV-grade CaF2 single crystals using ZnF2 additive asscavenger

CaF2 single crystals suitable for excimer laser application in the ultravio let range were grown by the Czochralski method. ZnF2 additive and CF4 gas w ere successfully used as scavengers for removing the water molecules in the growth environment, which otherwise cause various defects such as subgrain boundaries, bubbles and oxygen-related precipitates in the CaF2 crystal. C zochralski-grown CaF2 crystals had very good crystallinity and a high trans mittance in the wavelength range of the ultraviolet laser. The defect struc tures of colored and colorless CaF2 crystals were compared. (C) 2001 Elsevi er Science B.V. All rights reserved.