>1.8 millisecond effective lifetime in n-type silicon grown by the noncontact crucible method

Maulid Kivambe*, Douglas M. Powell, Mallory Ann Jensen, Ashley E. Morishige, Kazuo Nakajima, Ryota Murai, Kohei Morishita, Tonio Buonassisi

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

We evaluate the performance and gettering response of n-type ingot silicon material grown by the noncontact crucible method for photovoltaic applications. As-grown lifetimes are >150 μs and relatively homogeneous through the ingot. We apply standard and extended gettering profiles to elucidate gettering response. Effective minority carrier lifetimes are greater than 700 μs and 1.8 ms at an injection condition of 1015 cm-3 after standard and extended gettering schemes, respectively, on samples from near the top of an ingot. Unlike the as-grown state, the wafer lifetime distribution in gettered samples is not homogeneous. In wafers from lower parts of the ingot, concentric-swirl patterns of lower lifetime are revealed after gettering. We hypothesize that gettering removes a large percentage of fast-diffusing impurities, while defect striations similar to swirl microdefects found in Czochralski silicon can in some cases continue to limit lifetimes after gettering. These results indicate that, by application of a tailored gettering process, silicon materials grown by the noncontact crucible method can achieve lifetimes that can readily support high-efficiency solar cells, while highlighting areas for further material improvement.

Original languageEnglish
Title of host publication2014 IEEE 40th Photovoltaic Specialist Conference, PVSC 2014
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages2988-2990
Number of pages3
ISBN (Electronic)9781479943982
DOIs
Publication statusPublished - 15 Oct 2014
Externally publishedYes
Event40th IEEE Photovoltaic Specialist Conference, PVSC 2014 - Denver, United States
Duration: 8 Jun 201413 Jun 2014

Publication series

Name2014 IEEE 40th Photovoltaic Specialist Conference, PVSC 2014

Conference

Conference40th IEEE Photovoltaic Specialist Conference, PVSC 2014
Country/TerritoryUnited States
CityDenver
Period8/06/1413/06/14

Keywords

  • defect engineering
  • gettering
  • impurities
  • lifetime
  • noncontact crucible method
  • passivation
  • silicon

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