Photoluminescence imaging of chromium in crystalline silicon

In this work a method for the quantitative and spatially resolved detection of dissolved chromium is presented. For the quantitative evaluation of the Cr_i concentration the defect parameters (capture cross sections and energy levels) for Cr_i and CrB from literature are reviewed and compared to measurements. The method is applied to mono- and multicrystalline samples with different doping and Cr contamination levels. From the significant difference of the lifetime observed in both Cr states a quantitative image of the interstitial chromium concentration has been deduced and compared to predictions for Cr-distribution in ingots. The association time of the CrB formation process is determined by time dependent measurements. Reasonable agreement is found with other published data. Based on spatially resolved Cr_i-images conclusions of the distribution of dissolved Cr with respect to grains, dislocation clusters and grain boundaries are drawn which exemplify the value of this new method.