Changes in hydrogen concentration and defect state density at the poly-Si/SiOx/c-Si interface due to firing

We determined the density of defect states of poly-Si/SiOx/c-Si junctions featuring a wet chemical interfacial oxide from lifetime measurements using the MarcoPOLO model to calculate recombination and contact resistance in poly-Si/SiOx/c-Si-junctions. In samples that did not receive any hydrogen treatment, the Di(t),(cSi) is about 2 x 10(12) cm(-2) eV(-1) before firing and rises to 3-7 x 10(12) cm(-2) eV(-1) during firing at measured peak temperatures between 620 degrees C and 863 degrees C. To address the question of why Al0 x /SiN y stacks in contrast to pure SiN y layers for hydrogenation during firing provides better passivation quality, we have measured the hydrogen concentrations at the poly-Si/SiOx/c-Si interface as a function of AlOx layer thickness and compared these to J(0) and calculated si values. We observe an increase of the hydrogen concentration at the SiOx/c-Si interface upon firing as a function of the firing temperature that exceeds the defect concentrations at the interface several times. However, the AlOx layer thickness appears to cause an increase in hydrogen concentration at the SiOx/c-Si interface in these samples rather than exhibiting a hydrogen blocking property.

Automated summary

The study determined the density of defect states in poly-Si/SiOx/c-Si junctions and found that the hydrogen concentration at the SiOx/c-Si interface increased during firing, exceeding the defect concentrations several times. However, the thickness of the AlOx layer may cause an increase in hydrogen concentration at the SiOx/c-Si interface instead of exhibiting a hydrogen-blocking property.