| 简介 |
PROBLEM TO BE SOLVED : To provide high purity cerium suitable for a sputtering target material for manufacturing a gate insulation film in next generation MOSFET, and a technology for stably manufacturing the high purity cerium.SOLUTION : There is provided high purity cerium, having purity excluding a gas component of 4 N 5 or more and obtained by preparing cerium having purity of 4 N or more by reducing a raw material of cerium fluoride having purity excluding the gas component of 4 N or more with distillate calcium having Cu of less than 2 ppm, and removing volatile materials by electron beam melting the reduced cerium. There is provided high purity cerium in which preferably Al, Fe, Cu are 10 wtppm or less respectively, total amount of W, Mo, Ta is 100 wtppm or less, and total amount of rear earth elements other than cerium is 10 wtppm or less. There is provided high purity cerium in which further preferably total amount of the gas component is 1000 wtppm or less and C is 200 wtppm or less.SELECTED DRAWING : NoneCOPYRIGHT : (C)2018, JPO&INPIT |
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