Table of Contents
Journal of Solar Energy
Volume 2013, Article ID 183812, 20 pages
http://dx.doi.org/10.1155/2013/183812
Review Article

Review of Ni-Cu Based Front Side Metallization for c-Si Solar Cells

Solar Lab, Department of Energy Science and Engineering, National Center for Photovoltaic Research and Education (NCPRE), Indian Institute of Technology Bombay, Powai, Mumbai 400076, India

Received 10 April 2013; Revised 12 September 2013; Accepted 24 September 2013

Academic Editor: Haricharan S. Reehal

Copyright © 2013 Mehul C. Raval and Chetan S. Solanki. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Given the high percentage of metal cost in cell processing and concerns due to increasing Ag prices, alternative metallization schemes are being considered. Ni-Cu based front side metallization offers potential advantages of finer grid lines, lower series resistance, and reduced costs. A brief overview of various front side patterning techniques is presented. Subsequently, working principle of various plating techniques is discussed. For electroless plated Ni seed layer, fill factor values nearing 80% and efficiencies close to 17.5% have been demonstrated, while for Light Induced Plating deposited layers, an efficiency of 19.2% has been reported. Various methods for qualifying adhesion and long term stability of metal stack are discussed. Adhesion strengths in the range of 1–2.7 N/mm have been obtained for Ni-Cu contacts tabbed with conventional soldering process. Given the significance of metallization properties, different methods for characterization are outlined. The problem of background plating for Ni-Cu based metallization along with the various methods for characterization is summarized. An economic evaluation of front side metallization indicates process cost saving of more than 50% with Ni-Cu-Sn based layers. Recent successful commercialization and demonstration of Ni-Cu based metallization on industrial scale indicate a potential major role of Ni-Cu based contacts in near future.