AN APPARATUS FOR MEASURING CARRIER LIFETIMES IN A SEMICONDUCTOR

摘要

A carrier lifetime measuring apparatus according to the present invention has a construction wherein a first photon beam of a wavelength capable of rendering the optical absorption coefficient of a semiconductor sample very small when the semiconductor sample having a potential barrier in the vicinity of its surface is irradiated with the radiation, and a second photon beam of a wavelength capable of rendering the optical absorption coefficient very large are respectively chopped to alternately irradiate the identical place of the semiconductor sample with the chopped beams; first and second photovoltages which are generated in the semiconductor sample by these photon beams are detected by capacitance coupling; and the ratio between a first amplitude variation and a second amplitude variation is obtained from the amplitudes of the detected photovoltages; thereby to evaluate a minority carrier lifetime in the semiconductor sample.