| 摘要 |
<p>Disclosed is highly pure lanthanum which has a purity of 4 N or more as determined by excluding any rare earth element or any gaseous component therefrom, and which contains aluminum, iron and copper each in an amount of 100 wtppm or less. Also disclosed is highly pure lanthanum, which has a purity of 4 N or more as determined by excluding any rare earth element or any gaseous component therefrom, which contains aluminum, iron and copper each in an amount of 100 wtppm or less, which contains oxygen in an amount of 1500 wtppm or less, which contains an alkali metal element and an alkali earth metal element each in an amount of 1 wtppm or less, which contains a transition metal element and a high-melting-point metal element other than those mentioned above each in an amount of 10 wtppm or less, and which contains a radioactive element in an amount of 10 wtppb or less. Further disclosed is a technique for efficiently and stably providing highly pure lanthanum, a sputtering target comprising a highly pure lanthanum material and a metal gate thin film mainly composed of a highly pure lanthanum material.</p> |
