Excellent boron emitter passivation for high‐efficiency Si wafer solar cells using AlOx/SiNx dielectric stacks deposited in an industrial inline plasma reactor

ABSTRACT Excellent passivation of boron emitters is realised using AlO x /SiN x dielectric stacks deposited in an industrial inline plasma‐enhanced chemical vapour deposition reactor. Very low emitter saturation current density ( J 0e ) values of 10 and 45 fA/cm 2 are obtained for 180 and 30 Ω/sq planar p + emitters, respectively. For textured p + emitters, the J 0e was found to be 1.5–2 times higher compared with planar emitters. The required thermal activation of the AlO x films is performed in a standard industrial fast‐firing furnace, making the developed passivation stack industrially viable. We also show that an AlO x thickness of 5 nm in the AlO x /SiN x stack is sufficient for obtaining a J 0e of 18 fA/cm 2 for planar 80 Ω/sq p + emitters, which corresponds to a 1‐sun open‐circuit voltage limit of the solar cell of 736 mV at 25 °C. Copyright © 2012 John Wiley & Sons, Ltd.