METHOD FOR FAST AND ACCURATE DETERMINATION OF THE MINORITY CARRIER DIFFUSION LENGTH FROM SIMULTANEOUSLY MEASURED SURFACE PHOTOVOLTAGES

Minority carrier diffusion lengths are determined fast, accurately, and conveniently by illuminating a surface of the semiconductor with a beam composed of a plurality of light fluxes each having a different wavelength modulated at a different frequency. Surface photovoltages induced by different light fluxes are simultaneously detected by monitoring surface photovoltage signals at the different modulation frequencies. The surface photovoltage signals are frequency calibrated and then used to calculated a minority carrier diffusion length.