| abstract |
The present invention relates to a method for purifying erbium which has a high vapor pressure and is difficult to purify in a molten metal state, a high-purity erbium obtained thereby, a sputtering target composed of erbium, and a high-purity material erbium. Provide metal gate thin films efficiently and stably. Crude erbium oxide is mixed with a reduced metal, heated in vacuum to reduce and distill erbium, and further dissolved in an inert atmosphere to obtain high-purity erbium. Using erbium oxide having a purity of 3N or less as a raw material, heating to a temperature of 1500 to 2500 ° C., and performing purification by reducing and distilling erbium, the oxygen content was 200 wtppm or less, and other impurities were set to a predetermined value or less. High purity erbium having a purity of 4N or more excluding rare earth elements and gas components is obtained. [Selection figure] None |