By Topic

Impact of Impurities From Crucible and Coating on mc-Silicon Quality—the Example of Iron and Cobalt

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$33 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

11 Author(s)
Martin C. Schubert ; Fraunhofer Institute for Solar Energy Systems, Freiburg, Germany ; Jonas Schön ; Florian Schindler ; Wolfram Kwapil
more authors

The aim of this paper is to analyze the limiting role of crucible and coating impurities on material quality of multicrystalline silicon. Both solid body diffusion and diffusion into the silicon melt are considered in this study. Two ingots of size G1 have been analyzed. One of them was crystallized in a standard crucible, whereas the other was crystallized in a quartz crucible of very high purity. Focus is put on iron and cobalt as examples of typical impurity species. Iron was found in large concentrations in standard crucibles, and cobalt was proven to be a suitable marker impurity that is mainly found in the coating. Inductively coupled plasma mass spectroscopy data are exploited for the determination of impurity concentrations in crucible, coating, and within the crystal. With higher sensitivity for low concentration, PL imaging is applied for carrier lifetime and interstitial iron concentration measurements. The different findings are compared with modeling results of iron and cobalt in-diffusion by Sentaurus Process. The analysis of silicon wafers before and after gettering steps enable a quantification of impurity-limiting cell efficiency potential. Conclusions about the role of impurities from coated crucibles in large-scale crystallization are deduced.

Published in:

IEEE Journal of Photovoltaics  (Volume:3 ,  Issue: 4 )