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 Cri concentration the defect parameters (capture cross sections and energy levels) for Cri 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 Cri-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.