| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing high purity ruthenium suitably used, e.g. for starting material for a material for high purity ruthenium oxide thin film formation and reduced in the contents of alkali metals, such as Na and K, heavy metals, such as Fe and Ni, and radioactive elements, such as U and Th, and further to obtain a high purity ruthenium material for thin film formation, reduced in resistance and also capable of reducing the occurrence of particles at the time of sputtering. SOLUTION: The high purity ruthenium can be produced by blowing an ozone- containing gas whole adding hypochlorous acid into a crude ruthenium powder to form ruthenium tetroxide, allowing the ruthenium tetroxide to be absorbed by a hydrochloric acid solution, further evaporating the solution to dry and solidify it, and roasting the resultant RuOCl3 crystals in a hydrogen atmosphere. By this method, the high purity ruthenium material for thin film formation, which contains <1 ppm each of alkali metal elements, <1 ppm each of alkaline earth metal elements, <1 ppm each of transition metal elements, <10 ppb each of radioactive elements, and <500 ppm, in total, of carbon and gas computer elements (oxygen, hydrogen, nitrogen, chloride) and in which the purity of ruthenium excluding the gas component elements is regulated to >=99.995%, is obtained. |
