Lifetime Degradation in Dark Observed in Mono Crystalline Cz-Silicon

In this work, we report minority charge carrier lifetime degradation in dark of up to 20 μs at room temperature in air ambient in P-gettered Cz-Si wafers passivated with PECVD SiNx. We have shown that this effect is dominated by the bulk and not effected by the surface or the measurement. The degradation is much slower than the degradation observed during the light induced degradation (LID) process. Furthermore, increase in substrate temperature slows down the degradation in dark (DID) mechanism to large extend. The substrates show very fast LID when exposed to light and the light induced defects can be repaired within a few seconds by an annealing at 200°C. In the degraded states of LID and DID, the characteristic rings of Cz-Si material are visible. It indicates that the DID mechanism is driven by the B-O complexes in the bulk of the material. In order to observe this effect, which was not found yet by other groups, we assume that our material has high oxygen concentration, low Fei concentration and high dislocation density.