Photovoltaic cells are conventionally electrically isolated (isolation) and then separated from the wafer (singulation) by saw dicing at the end of the fabrication process. However, saw dicing presents limitations in terms of cell shapes and causes excessive material losses. We propose isolation and singulation by plasma etching as an alternative to saw dicing. The etching process proposed also allows via hole etching for through cell via contacts (TCVC) [1]. This technology uses isolated metallized vias to carry front-side generated carriers to the backside. This new architecture could increase the efficiency and increase the energy production per wafer for concentrated photovoltaic (CPV) cells. In this paper, those two plasma etching applications for CPV cell fabrication are discussed. More precisely, triple junction solar cells have been fabricated with either a plasma singulation or with via holes and compared with reference cells (without via hole and saw dicing singulation). One sun IV measurements, external quantum efficiency (EQE) and 100 suns IV characteristics show that no performance losses can be observed on cells with plasma singulation. Via hole etching induces open circuit voltage (VOC) and fill factor (FF) losses below 3 % that can be recovered with a surface passivation.

1.
O.
Richard
,
A.
Jaouad
,
B.
Bouzazi
,
R.
Arès
,
S.
Fafard
and
V.
Aimez
, “
Simulation of through cell via contacts architecture for HCPV multi-junction solar cells
,”
Solar Energy Materials and Solar cells
, vol.
144
, pp.
173
180
,
2016
.
2.
O.
Richard
,
M.
Volatier
,
M.
Darnon
,
A.
Jaouad
,
B.
Bouzazi
,
R.
Arès
,
S.
Fafard
,
V.
Aimez
, “
Through cell vias contacts for multijunction solar cells
,”
AIP Conference Proceedings
,
1679
,
060003
,
2016
.
3.
T.
Stellwag
,
P.
Dodd
,
M.
Carpenter
,
M.
Lundstrom
,
R.
Pierret
,
M.
Melloch
,
E.
Yablonovitch
, and
T.
Gmitter
, “
Effects of perimeter recombination on GaAs-based solar cells
IEEE Conference on Photovoltaic Specialists
, no.
100
,
1990
.
4.
M. G.
Mauk
,
S.
Xu
,
D. J.
Arent
,
R. P.
Mertens
, and
G.
Borghs
, “
Study of novel chemical surface passivation techniques on GaAs pn junction solar cells
Applied Physics Letters
, vol.
54
, no.
1989
, pp.
213
215
,
1989
.
5.
M.
Darnon
,
M.
de Lafontaine
,
M.
Volatier
,
S.
Fafard
,
R.
Arès
,
A.
Jaouad
,
V.
Aimez
, “
Deep germanium etching using time multiplexed plasma etching
,”
Journal of Vacuum Science & Technology B
,
33
,
060605
,
2015
,
6.
G.
Siefer
,
C.
Baur
, and
A. W.
Bett
, “
External quantum efficiency measurements of germanium bottom subcells: Measurement artifacts and correction procedures
,”
Photovoltaic Specialists Conference (PVSC), 35ᵗʰ IEEE
,
Honolulu, HI
, pp.
704
707
,
2010
.
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