Abstract
The search for an ideal surface passivation layer of crystalline silicon
(
c
-
Si
)
to be employed in a silicon heterojunction photovoltaic device has garnered much attention. The leading candidate is a few nanometers of intrinsic amorphous silicon
(
(
i
)
a
-
Si
:
H
)
film. Reported dependencies of film surface passivation quality on substrate preparation, orientation, and deposition temperature have been extended in this work to include
H
2
to
Si
H
4
dilution ratio and postdeposition annealing. Simple avoidance of the deposition regimes that lead to epitaxial growth of Si on the
c
-
Si
substrate produces decent lifetimes on the order of
500
μ
s
. Subsequent low temperature annealings cause an important restructuring of Si-H bonding at the
a
-
Si
:
H
∕
c
-
Si
interface increasing the amount of monohydride at the
c
-
Si
surface. This restructuring would reduce the
c
-
Si
surface defect density and cause an improvement of surface passivation as confirmed by effective lifetime measurements. Final effective carrier lifetimes up to
2550
μ
s
are achieved postannealing. Initial results indicate the improvement depends on surplus
Si
H
2
from the interface region.