Ga segregation during Czochralski-Si crystal growth with Ge codoping

摘要

The segregation of Ga during the growth of Czochralski-Si crystals with Ge codoping was investigated. The effective segregation coefficient of Ga in Ga/Ge-codoped Si crystal growth was nearly constant over a wide Ge concentration range, even at high Ge concentrations of about 10~(21) cm~(-3). In contrast, the effective segregation coefficient increased at high B concentrations in Ga/B-codoped CZ-Si crystal growth. The segregation behavior of Ga in Ga/Ge- and Ga/B-codoped CZ-Si crystal growth was theoretically compared. The difference in the segregation coefficients of Ga as a function of the codoped impurity (Ge or B) between the two Si crystals was attributed to a difference in the excess enthalpy due to impurity incorporation into the Si crystal between Ga-Ge pairs and Ga-B pairsrnThe effect of Ge codoping on the minority carrier lifetime in Ga/Ge-codoped CZ-Si crystals was also investigated. The minority carrier lifetime increased with increasing Ge concentration. The higher minority carrier lifetime was associated with a decrease in interstitial oxygen related to D-defects in the Si crystal.