A NEW METHOD FOR CLEANING THE SURFACE OF ULTRA HIGH-PURITY IRON BY HIGH-PURITY OZONE EXPOSURE AND UV IRRADIATION

A new method by applying high-purity ozone exposure and ultraviolet (U V) irradiation has been used for cleaning the surface of ultra high-pu rity iron with a carbon contaminated layer. The amount and chemical st ate of elements on the specimen surface were characterized by X-ray ph otoelectron spectroscopy. The intensity of the C 1s XPS peak due to ca rbon contamination was found to decrease with increasing ozone exposur e al room temperature. UV irradiation during ozone exposure enhanced t he cleaning rare. The XPS results show that contaminated carbon is mai nly classified into major aliphatic carbon and minor carboxyl carbon, and their ratio depends upon the condition of ozone exposure. The role of ozone exposure and UV irradiation was discussed with respect to su rface cleaning.