A method for producing high-purity lanthanum, high-purity lanthanum, metal gate film mainly the sputtering target and high purity lantern made of a high-purity lanthanum

摘要

[Abstract] A high-purity lanthanum, is the purity excluding rare-earth elements and gas components is above 5N, a high-purity lanthanum α ray count and wherein the at 0.001cph / cm ² or less. The raw material purity of less coarse lanthanum metal 4N excluding gas components, and the molten salt electrolysis at a bath temperature of 450~700 ° C to obtain a lanthanum crystals, then the lantern crystals, after desalted, and electron beam melting and to remove the volatiles is equal to or higher than the purity is 5N excluding rare earth elements and gas components, method for producing a high-purity lanthanum α ray count, characterized in that the 0.001cph / cm ² or less. Low α-ray high-purity lanthanum, it is an object of the present invention to provide an efficient and stable technology that can be provided a thin film for metal gate mainly composed of sputtering target and high purity material lantern made of a high-purity material lantern. .BACKGROUND