Jx Nippon Mining Metals Corporation

Takeshi Gohara

Masahiro Takahata

Satoyasu Narita

Kazuyuki Satoh

A method for producing high-purity lanthanum having a purity of 4N or more excluding rare earth elements other than lanthanum and gas components, wherein lanthanum having a purity of 4N or more is produced by reducing, with distilled calcium, a lanthanum fluoride starting material that has a purity of 4N or more excluding rare earth elements other than lanthanum and gas components, and the obtained lanthanum is subjected to electron beam melting to remove volatile substances. The method for producing high-purity lanthanum, in which Al, Fe, and Cu are respectively contained in the amount of 10 wtppm or less. The method for producing high-purity lanthanum, in which total content of gas components is 1000 wtppm or less. The present invention aims to provide a technique capable of efficiently and stably providing high-purity lanthanum, a sputtering target composed of high-purity lanthanum, and a thin film for metal gate that contains high-purity lanthanum as a main component.

Production method for high-purity lanthanum, high-purity lanthanum, sputtering target composed of high-purity lanthanum, and metal gate film containing high-purity lanthanum as main component

The present invention addresses the problem of providing a technique capable of efficiently and stably providing a method for producing high-purity lanthanum, the method characterized in that: a crude lanthanum oxide starting material having a purity of 2N-3N, excluding gas components, is used; the material is subjected to molten salt electrolysis at a bath temperature of 450-700&#xb0; C. to produce lanthanum crystals; the lanthanum crystals are subsequently desalted: and electron beam melting is then performed to remove volatile substances. The present invention also addresses the problem of providing a technique capable of efficiently and stably providing high-purity lanthanum, high-purity lanthanum itself, a sputtering target formed from high-purity material lanthanum; and a thin film for metal gates that has high purity lanthanum as the main component.

Method for producing high-purity lanthanum, high-purity lanthanum, sputtering target formed from high-purity lanthanum, and metal gate film having highy-purity lanthanum as main component

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Ibaraki, Japan

Takeshi Gohara