TY - JOUR
T1 - High temperature oxidation pre-treatment of textured c-Si wafers passivated by a-Si:H
AU - Limodio, G.
AU - D'Herouville, G.
AU - Mazzarella, L.
AU - Zhao, Y.
AU - Yang, G.
AU - Isabella, O.
AU - Zeman, M.
N1 - Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.
PY - 2019
Y1 - 2019
N2 -
This work shows an alternative surface cleaning method for c-Si wafers to replace the standard chemical procedures as RCA or HNO
3
which involve hazardous chemicals or unstable processes. The method consists in a high-temperature oxidation treatment (HTO) performed in a classical tube furnace that incorporates organic and metal particles present on the c-Si surfaces in the growing SiO
2
layer. The result is as a reliable pre-treatment method for obtaining less defective c-Si surfaces ready for solar cell fabrication after SiO
2
removal. To test the surface passivation quality obtained with our alternative cleaning method, we grow amorphous silicon (a-Si:H) layers by plasma enhanced chemical vapor deposition on both sides of the c-Si wafer and systematically compare the effective carrier lifetime (τ
eff
) and implied V
OC
(iV
oc
) to the wafer treated with the standard cleaning in our laboratory. We optimize HTO treatment time reaching τ
eff
of ∼6 ms and iV
oc
of 721 mV for the best sample. We ascribe the improved passivation quality using HTO to two concurrent factors. Firstly, the encapsulation of defects into SiO
2
layer that is then etched prior a-Si:H deposition and secondly, to modification of the pyramids’ morphology that facilitates the surface passivation. SEM pictures and reflection measurements support the latter hypothesis.
AB -
This work shows an alternative surface cleaning method for c-Si wafers to replace the standard chemical procedures as RCA or HNO
3
which involve hazardous chemicals or unstable processes. The method consists in a high-temperature oxidation treatment (HTO) performed in a classical tube furnace that incorporates organic and metal particles present on the c-Si surfaces in the growing SiO
2
layer. The result is as a reliable pre-treatment method for obtaining less defective c-Si surfaces ready for solar cell fabrication after SiO
2
removal. To test the surface passivation quality obtained with our alternative cleaning method, we grow amorphous silicon (a-Si:H) layers by plasma enhanced chemical vapor deposition on both sides of the c-Si wafer and systematically compare the effective carrier lifetime (τ
eff
) and implied V
OC
(iV
oc
) to the wafer treated with the standard cleaning in our laboratory. We optimize HTO treatment time reaching τ
eff
of ∼6 ms and iV
oc
of 721 mV for the best sample. We ascribe the improved passivation quality using HTO to two concurrent factors. Firstly, the encapsulation of defects into SiO
2
layer that is then etched prior a-Si:H deposition and secondly, to modification of the pyramids’ morphology that facilitates the surface passivation. SEM pictures and reflection measurements support the latter hypothesis.
KW - Amorphous silicon passivation
KW - Defect encapsulation
KW - Silicon heterojunction solar cells
KW - Thermal oxidation
UR - http://www.scopus.com/inward/record.url?scp=85062860268&partnerID=8YFLogxK
U2 - 10.1016/j.mssp.2019.03.008
DO - 10.1016/j.mssp.2019.03.008
M3 - Article
AN - SCOPUS:85062860268
VL - 97
SP - 67
EP - 70
JO - Materials Science in Semiconductor Processing
JF - Materials Science in Semiconductor Processing
SN - 1369-8001
ER -