Aluminum-Based Rear-Side PVD Metallization for nPERT Silicon Solar Cells

Author

Katkhouda, Kamal ; Martinez-Limia, Alberto ; Bornschein, Lutz ; Koseva, Radinka ; Geppert, Torsten ; Grohe, Andreas ; Krokoszinski, Hans-Joachim ; Schaaf, P.

Author_Institution

Bosch Solar Energy, Arnstadt, Germany

Volume

4

Issue

1

fYear

2014

fDate

Jan. 2014

Firstpage

160

Lastpage

167

Abstract

This paper presents the results of a detailed study on Al-based physical vapor deposition metallization for the rear side of nPERT silicon solar cells. Pure Al is compared with a barrier metallization (Al-Si/Al or Ti/Al) in terms of spiking, contact formation and back-side reflection. A degradation of cell performance with pure Al rear-side metallization due to Al spiking after thermal annealing is observed. This can be avoided either by using a spiking barrier or by using a sufficiently deep doping profile. In addition, all metallization schemes have a sufficiently low specific contact resistance <;0.2 mΩ·cm² on n⁺-Si with a sheet resistance of ~75 Ω/sq. Furthermore, the widely used front-side contact metal Ti leads to a significant short-circuit current density loss of more than 0.3 mA/cm² when applied to the rear side of a silicon solar cell due to its low reflectivity of infrared wavelengths.

Keywords

aluminium; annealing; contact resistance; current density; doping profiles; elemental semiconductors; reflectivity; semiconductor device metallisation; silicon; solar cells; titanium; vapour deposition; Al; Al-Si-Al; Si; Ti-Al; aluminum-based rear-side PVD metallization; back-side reflection; barrier metallization; contact formation; contact resistance; deep doping profile; infrared wavelength reflectivity; nPERT silicon solar cells; physical vapor deposition metallization; sheet resistance; short-circuit current density loss; spiking barrier; thermal annealing; Annealing; Contact resistance; Metallization; Photovoltaic cells; Resistance; Silicon; Metallization; physical vapor deposition (PVD); rear totally diffused (PERT); silicon solar cell;

fLanguage

English

Journal_Title

Photovoltaics, IEEE Journal of

Publisher

ieee

ISSN

2156-3381

Type

jour

DOI

10.1109/JPHOTOV.2013.2288018

Filename

6670052