Enrichment of daughter nuclides of natural alpha-decay series in high purity aluminum for LSI fabrication

摘要: Uranium and thorium isotopes were determined in highly pure aluminum for LSI fabrication by alpha-spectrometry utilizing natural 147Sm as an inner standard. Daughter nuclides decay series are found enrichment state from radioactive equilibrium. Unexpected contamination that had a ground water origin was supposed to explain the enrichment. This finding suggests strongly is still quite important technique evaluate soft-error probability modern memory device materials since sensitive instrumental analysis such ICP-MS not enough short-lived alpha-emitters.