Defect sites in Si, which temporarily capture excess charge carriers (traps), were a promising source of information on defect structures. The correlation between traps in p-type silicon, structural crystal defects, and impurities was explored here in order to find the origin of these traps in multicrystalline silicon. The trap density was compared to the density of different impurities and structural crystal defects. These comparisons revealed that the trap density was positively correlated with the oxygen density and negatively correlated with the density of the metallic impurities analyzed. In addition, it was shown that structural crystal defects were necessary but not sufficient for the existence of high trap densities. In summary, structural crystal defects that were decorated by O precipitates arose as the likely cause of trap centers.

Origin of Trapping in Multicrystalline Silicon. P.Gundel, M.C.Schubert, W.Warta: Journal of Applied Physics, 2008, 104[7], 073716