Effect of PECVD silicon oxynitride film composition on the surface passivation of silicon wafers

This work presents a quantitative analysis on the relationship between the composition of PECVD silicon oxynitride and surface passivation on float zone silicon wafers with planar non-diffused surfaces using FTIR spectroscopy. Implied open circuit voltages of approximately 740 mV are demonstrated on both n-type and p-type substrates, with associated 1-sun effective minority carrier lifetimes of 1.8 ms and 1.1 ms respectively. Improvements in the implied open circuit voltage of up to 80 mV upon thermal annealing are presented for films with Si–H peak wavenumbers >2200cm−1 and are attributed to increasing oxygen incorporation.

► 740 mV implied open circuit voltage achieved on n-type and p-type substrates.
► Increasing oxygen incorporation can lead to higher improvements through annealing.
► SiON provides excellent front and rear surface passivation for silicon solar cells.