The impact of the FeGa complex on directionally solidified, mono-crystalline, Ga-doped silicon

Abstract

In this work we show that the high minority carrier lifetime in as-grown Ga-Si wafers is dominated by low levels of iron contamination incorporated during silicon growth. Upon phosphorous diffusion iron is however effectively removed, increasing the bulk carrier lifetime from a few hundred microseconds to well above one milli-second. Lifetime spectroscopy in combination with Shockley Read Hall theory was used to determine the concentrations of Fe i and FeGa complexes in the course of the FeGa association. Finally, we use the estimated concentrations of FeGa as a function of time of storage in the dark to validate that FeGa association follows the laws of coulombic attraction similar to FeB.