Investigation of interface properties in oxide passivated boron diffused silicon

Electron paramagnetic resonance (EPR) measurements were employed to observe the dominant defect at the thermally grown (1 1 1) Si–SiO2 interface, namely the Pb center, of samples with oxides grown at moderate temperatures. The presence of boron diffusion leads to an increase of the Pb density by a factor of ∼1.6 to 1.8, significantly less than previously reported for higher temperature oxides. The Pb density for samples with similar emitter sheet resistances but different (by a factor of 4) boron surface concentrations were similar, suggesting that the increase in Pb concentration following is primarily determined by the total boron dose. Investigations of the stability of the passivation of boron diffused, oxide passivation emitters strongly suggest that degradation is the result of the permeability of SiO2 to moisture, which can be prevented through the addition of a moisture barrier.