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On the shape of n-type Czochralski silicon top ingots

Abstract

Industrial scale n-type monocrystalline silicon ingots with different crown shape and shouldering area have been grown and characterized in terms of minority carrier lifetime, resistivity and concentration and distribution of interstitial oxygen (Oi), voids and thermal donors (TD). The properties have been correlated with the process parameters. The results indicate that there is a relationship between the top ingot shape and the corresponding minority carrier lifetime quality of the first part of the ingot body. Oxygen incorporation is directly correlated to the time that the melt free surface is in contact with the purged gas atmosphere as well as the temperature of the melt. The relative P-band position is dependent on the process parameters at the early part of the ingot and the corresponding oxide particles could be included on the first wafers obtained from the ingot. The results also show that the early body quality is not always improved after TD annealing. This suggests that not all types and sizes of TD are dissolved during standard annealing processes. Other types of oxygen-related defects are most likely present and contribute to the lowered minority carrier lifetime found at this region. Both higher oxygen and vacancy concentration contribute to the formation of these defects.

Category

Academic article

Language

English

Author(s)

Affiliation

  • Norwegian University of Science and Technology
  • SINTEF Industry / Sustainable Energy Technology
  • Institute for Energy Technology

Year

2015

Published in

Journal of Crystal Growth

ISSN

0022-0248

Publisher

Elsevier

Volume

418

Page(s)

176 - 184

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