Evaluation of ultra-long bulk lifetime of Czochralski-grown silicon crystals using direct-current photoconductive decay method

Abstract

A measurement technique for obtaining the correct bulk lifetime using the direct-current photoconductive decay (DC-PCD) method was investigated. To accurately measure the long minority carrier lifetime using the DC-PCD method, the sample should be sufficiently larger than the carrier diffusion length. We confirmed that the bulk lifetime of 40 ms can be measured using a rectangular sample with a sectional area larger than 1200 mm 2 . We demonstrated the measurement of a long bulk lifetime by applying appropriate sample dimensions even though the upper limit of the carrier lifetime exceeded the value assumed in the JIS standard. © 2019 The Japan Society of Applied Physics where x, y, and z are the dimensions of rectangular-shaped samples, and D is the diffusion coefficient of the minority