Passivation of highly boron doped silicon surfaces by sputtered AlOx and PECVD SiN, a comparison

We show that boron-diffused emitters can be passivated with AlO
_x
deposited using RF sputtering of an Al target. The surface passivation achieved so far is inferior to that obtained using an optimised PECDV SiN process that includes a chemically grown SiO
₂
interfacial layer. Nevertheless, the levels of passivation obtained, expressed by emitter recombination current densities of J
_oE
=228-349 fA/cm
²
for sheet resistances of 88-210 Ω/□, are already consistent with solar cell with efficiencies in the 20% range.