Impact of extended contact co-firing on multicrystalline silicon solar cell parameters

Peral Boiza, Ana and Dastgheib-Shirazi, Amir and Fano, Vanesa and Jimeno, Juan Carlos and Hahn, Giso and Cañizo Nadal, Carlos del (2017). Impact of extended contact co-firing on multicrystalline silicon solar cell parameters. "IEEE Journal of Photovoltaics", v. 7 (n. 1); pp. 91-96. ISSN 2156-3381. https://doi.org/10.1109/JPHOTOV.2016.2621342.

Description

Title: Impact of extended contact co-firing on multicrystalline silicon solar cell parameters
Author/s:
  • Peral Boiza, Ana
  • Dastgheib-Shirazi, Amir
  • Fano, Vanesa
  • Jimeno, Juan Carlos
  • Hahn, Giso
  • Cañizo Nadal, Carlos del
Item Type: Article
Título de Revista/Publicación: IEEE Journal of Photovoltaics
Date: January 2017
ISSN: 2156-3381
Volume: 7
Subjects:
Freetext Keywords: Co-firing step, Low Thermal Annealing, extended gettering, contact formation.
Faculty: Instituto de Energía Solar (IES) (UPM)
Department: Electrónica Física
UPM's Research Group: Silicio y Nuevos Conceptos para Células Solares
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

During the temperature spike of the contact co-firing step in a solar cell process, it has been shown that the concentration of lifetime-killer dissolved metallic impurities increases, while adding an annealing after the spike getters most of the dissolved impurities towards the phosphorus emitter, where they are less detrimental. The contact co-firing temperature profile including the after-spike annealing has been called extended contact co-firing, and it has also been proposed as a means to decrease the emitter saturation current density of highly doped emitters, benefiting thus a wide range of materials in terms of detrimental impurity content. The aim of the present work is to determine the effect of performing this additional annealing on contact quality and solar cell performance, looking for an optimal temperature profile for reduction of bulk and emitter recombination without affecting contact quality. It presents the effect of the extended co-firing step on fill factor, series resistance and contact resistance of solar cells manufactured with different extended co-firing temperature profiles. Fill factor decreases when extended co-firing is performed. Series resistance and contact resistance increase during annealing, more dramatically when the temperature peak is decreased. Scanning Electron Microscopy (SEM) images show silver crystallites in contact with silver bulk before the annealing that allow a direct current path, and silver crystallites totally surrounded by glass layer (>100 nmthick) after annealing. Glass layer redistribution and thickening at low temperatures at the semiconductor-metal interface can be related to the series resistance increase. Degradation of series resistance during the temperature spike, when it is below the optimum one, can be also attributed to an incomplete silicon nitride etching and silver crystallite formation. To make full use of the beneficial effects of annealing, screen-printing metallic paste development supporting lower temperatures without thick glass layer growth is needed.

Funding Projects

TypeCodeAcronymLeaderTitle
Government of SpainEEBB-I-14-08268UnspecifiedUnspecifiedUnspecified
Government of SpainEEBB-I-15-09198UnspecifiedUnspecifiedUnspecified
Government of SpainENE2014-56069-C4-2-RTABACOUniversidad Politécnica de MadridCélulas tandem en silicio de bajo coste con obleas muy delgadas y procesos apropiados
Madrid Regional GovernmentS2013/MAE-2780MADRID-PVMartí Vega, AntonioMateriales, dispositivos y tecnología para el desarrollo de la Industria fotovoltaica

More information

Item ID: 43733
DC Identifier: http://oa.upm.es/43733/
OAI Identifier: oai:oa.upm.es:43733
DOI: 10.1109/JPHOTOV.2016.2621342
Official URL: https://ieeexplore.ieee.org/document/7740880
Deposited by: Profesor Titular Carlos del Cañizo Nadal
Deposited on: 21 Oct 2016 08:15
Last Modified: 05 Jun 2019 10:32
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