Crystal growth and evaluation of ultra-long carrier lifetime Czochralski silicon

Abstract

Impact of the ultralow-carbon concentration of below 1 × 1015 atoms/cm3 and thermal history on the bulk lifetime of phosphorus (P)-doped magnetic-field-applied Czochralski (MCZ) silicon was investigated. In order to accurately measure the long bulk lifetime, a direct-current photoconductive decay method was applied to a rectangular sample with a sectional area larger than 400 mm2. The measurement of an ultra-long bulk lifetime of longer than 20 ms was demonstrated using the P-doped MCZ silicon with a carbon concentration of approximately 5 × 1014 atoms/cm3. Furthermore, the bulk lifetime of MCZ silicon with shorter exposure time at 300–600 °C was extremely short; we believe that the formation behavior of the carbon-related defects in the crystal growth process affect the bulk lifetime. Therefore, not only reducing the carbon concentration but also improving the thermal history at low temperature is effective for increasing the bulk lifetime of as-grown P-doped MCZ silicon.