High-purity erbium, sputtering target comprising high-purity erbium, metal gate film having high-purity erbium as main component thereof, and production method for high-purity erbium

摘要

High-purity erbium having: a purity of at least 5N, excluding rare-earth elements and gas components; no more than 1 wt ppm each of Al, Fe, Cu, and Ta; no more than 10 wt ppm of W; no more than 150 wt ppm of carbon; no more than 1 wt ppm each of alkali metals and alkali rare earth metals; no more than 10 wt ppm in total of other transition metal elements; and no more than 10 wt ppb each of the radioactive elements U and Th. The present invention addresses the problem of providing: a method for increasing the purity of erbium, which has a high vapor pressure and is difficult to purify in a molten state; high-purity erbium obtained by said method; and technology capable of efficiently and stably providing a sputtering target comprising high-purity material erbium and a metal gate thin film having the high-purity erbium as the main component.