Improved Phosphorus Emitter Passivation using Chemically Grown SiO2 Layer for Industrial-sized Selective Emitter PERC

We demonstrate the improvement of phosphorus emitter passivation for an industrial-sized passivated emitter and rear cell (PERC) with selective emitter (SE) structure using a method of nitric acid oxidation of silicon (NAOS) to form ultrathin SiO2layer. The results clearly show a significant impact of the presence of NAOS-SiO2 above emitters on all I-V parameters of PERCsWe observed an increase in the opencircuit voltage (Voc), and theshort-circuit current density(Jsc) along with strong improvements in the internal quantum efficiency (IQE) for short-wavelength photons. These improvements can be ascribed to the high level of chemical passivation, as clearly shown by a reduced interface trap density (Dit), and it is due to the less Shockley-Read-Hall recombination. The results presented here suggest that NAOS surface pretreatment is a very promising technology to improve the level of chemical passivation and thereby enhancing the industrialsized PERC performance.