**Progress in Photovoltaics: Research and Applications**

# Excellent boron emitter passivation for high-efficiency Si wafer solar cells using AlO_{x}/SiN_{x} dielectric stacks deposited in an industrial inline plasma reactor

_{x}

_{x}

Correspondence: Shubham Duttagupta, Solar Energy Research Institute of Singapore (SERIS), National University of Singapore (NUS), Singapore.

E-mail: shubham.duttagupta@nus.edu.sg

## ABSTRACT

Excellent passivation of boron emitters is realised using AlO* _{x}*/SiN

*dielectric stacks deposited in an industrial inline plasma-enhanced chemical vapour deposition reactor. Very low emitter saturation current density (*

_{x}*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

*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*

_{x}*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.