Understanding of the RTP-assisted Reduction of Hydrogen Dissociation from Defects in EFG Si

Presented at the 14th International Photovoltaic Science and Engineering Conference; Chulalongkorn University, Bangkok, Thailand; January 26-30, 2004.This paper shows that very short, one second, firing of screen-printed Al on the back and SiN(x) anti-reflection coating on the front can significantly enhance the bulk lifetime in EFG Si through SiN(x)-induced hydrogenation of defects. This process improved average minority carrier lifetime from 3 μs to 93 μs, resulting in the open-circuit voltages as high as 613 mV. It is proposed that rapid firing at an appropriate temperature enhances the retention of hydrogen at defect sites by minimizing the hydrogen dissociation from defects. This is supported by a combination of simulations and experiments which reveal that the dissociation of hydrogen is extremely rapid at or below firing temperature of 700°C