Purification of sputtering target metals for high-k insulator films of MOSFET devices

采用热等离子体弧技术对先进电子器件溅射靶金属Hf、Zr、Ti、La、Ce的提纯进行了研究。为了提纯Hf、Zr和Ti，采用氢等离子体弧熔炼(HPAM)，然后在常压下HPAM过程中显著降低了Fe、Al、Cu等挥发性金属杂质，从而获得了高纯金属。另一方面，对于La和Ce的提纯，采用了等离子弧区熔法(PZM)，然后通过Fe和Al等金属杂质的良好偏析以及La和Ce棒PZM过程中挥发性杂质Ca和Mn的汽化还原，获得了高纯度的La和Ce。

Purification of Hf, Zr, Ti, La and Ce, needed as the sputtering target metals for the advanced electronic devices, was examined by means of thermal plasma arc techniques. For purification of Hf, Zr and Ti, hydrogen plasma arc melting (HPAM) was used and, then, their high purity metals were obtained by the remarkable reduction of many volatile metallic impurities like Fe, Al, and Cu during HPAM under atmospheric pressure. On the other hand, for purification of La and Ce, plasma arc zone melting (PZM) was applied and, then, high purity both metals were prepared by the excellent segregation of several metallic impurities like Fe and Al and, furthermore, the vaporization reduction of volatile impurities like Ca and Mn during PZM of La and Ce rods.