Patent ID: 6982001
Filing Date: 2006-01-03
Classification: C01B,C01F,C30B

Abstract:
1. A method for growing a metal fluoride single crystal, said method comprising the steps of: placing a metal fluoride material of formula MF placing the vessel in a crystal growth furnace; reducing a pressure in the crystal growth furnace to a pressure of less than 10 exposing the fluoride material and surfaces in the furnace to a halogen containing plasma at a pressure in the range of 0.1–150 mm Hg at temperature in the range 200–800° C. for a selected time in the range of 1–120 hours; stopping the flow of plasma and reducing the pressure in the furnace to less than 10 heating the fluoride material to a temperature above its melting point; and cooling the melted fluoride material, using a selected time and temperature cycle to form a metal fluoride single crystal suitable for below 200 nm optical lithography wherein M is selected from the group consisting of calcium, barium, magnesium and strontium, and mixtures thereof.