PRODUCTION METHOD OF HIGH GRADE ERBIUM, HIGH GRADE ERBIUM, SPUTTERING TARGET COMPRISING HIGH GRADE ERBIUM, AND METAL GATE FILM MAKING HIGH GRADE ERBIUM MAIN COMPONENT

摘要

PROBLEM TO BE SOLVED: To provide a method for performing high grade making of erbium in which steam pressure is high and refinement is difficult in a metal melting state and high grade erbium obtained by the same, and to efficiently and stably provide a sputtering target comprising a high grade material erbium and a thin film for a metal gate making the high grade material erbium a main component.SOLUTION: Raw erbium oxide is mixed with a reduction metal and heated in vacuum to reduce and distillate the erbium, and further the same is dissolved in an inert atmosphere to obtain high grade erbium. The erbium oxide in which purity is at most 3 N is used as a raw material, heated at 1500-2500°C, the erbium are performed by reduction and distillation and is refined to obtain high grade erbium in which an oxygen content is at most 200 wtppm, the other contaminants are made at most a specified value, and a purity excluding a rare earth element and a gas composition is at least 4 N.