Imaging of the Interstitial Iron Concentration in B-doped C-si Based on Time-dependent Photoluminesccence Imaging

We report on measurements of the interstitial iron concentration in boron-doped crystalline silicon by measuring the dissociation rate of iron-boron pairs using a camera-based photoluminescence setup (dynamic Fei imaging). This approach enables us to identify the interstitial iron concentration without measuring absolute values of the carrier lifetime and without knowing the recombination properties of interstitial iron and iron-boron pairs in silicon. We take advantage of the dependence of the dissociation rate of iron-boron pairs on the interstitial iron concentration. Furthermore, we exploit the linear relationship between the excess carrier density and photoluminescence signal at low injection levels. This allows the determination of the relative FeB pair concentration directly from the measured PL signals in the associated and dissociated state of the FeB pairs without an additional calibration of the PL signal to excess carrier density.