| 摘要 |
PROBLEM TO BE SOLVED: To suppress the influence of a surface level of a wafer by charging the wafer with charges opposite to a conduction type of the wafer, radiating light to a surface of the wafer, generating excess carriers and measuring an amount of damping of the excess carriers. SOLUTION: The apparatus for measuring a recombination lifetime of excess carriers which is used in measuring an amount of heavy metal contamination of a semiconductor or the like has, for example, an ionizer 20 for casting ions on a wafer 30 to be measured which is placed on a wafer stage 10. Plus ions or minus ions are cast on the wafer if a conduction type of the wafer 30 input to a control part 18 is an n type or a p type. After a surface of the wafer 30 is charged, a pulse light is radiated to the surface of the wafer from a light source device 12, thereby generating excess carriers. Thereafter, microwaves are radiated and a recombination lifetime is measured. Since the charging to the surface brings electrons and holes into a state in which they are difficult to recombine via a surface level of the wafer 30, the excess carriers damp nearly via a level of the heavy metal.
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