Radiochemical neutron activation analysis of ultra-pure molybdenum-based microelectronic materials for detrimental impurities

A radiochemical neutron activation analysis method, based on the separation of the radionuclides by anion-exchange from a 20 mol/l HF/3% H₂O₂ medium, was applied to the analysis of ultra-high purity molybdenum oxide and molybdenum metal and high-purity molybdenum silicide for 29 elements including the detrimental impurities Co, Cr, Fe, K, Na, Ni, Th, U and Zn. The achievable limits of detection for these elements are between 0.02 ng/g (for Co) and 50 ng/g (for K). The results were compared with those obtained by glow discharge mass spectrometry, inductively coupled plasma atomic emission and mass spectrometry, isotope dilution mass spectrometry and slurry sampling and direct solid sampling ETAAS. On the basis of the comparison of the results, the feasibility of the methods for analysis of these ultrapure materials is discussed.Dedicated to Professor Dr. Dieter Klockow on the occasion of his 60th birthday