Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2024-12-27T02:29:33.434Z Has data issue: false hasContentIssue false

SIMS Study of C, O and N Impurity Contamination for Multi-Crystalline Si Solar Cells

Published online by Cambridge University Press:  21 March 2011

Larry Wang
Affiliation:
Evans Analytical Group, 810 Kifer Road, Sunnyvale, CA 94086, U.S.A.
R. S. Hockett
Affiliation:
Evans Analytical Group, 810 Kifer Road, Sunnyvale, CA 94086, U.S.A.
Get access

Abstract

This paper is a case study of using SIMS to quantitatively measure C, O and N impurity contamination at two sequential commercial process steps: (1) Si feedstock: 7N (modified Siemens) and 5N feedstock (UMG-Si); and (2) multi-crystalline (mc-Si) solar wafers: cut and etched, from directional solidification bricks grown from 7N and 7N/5N (80:20) feedstock. The conclusion of this study is twofold: (a) the primary opportunity to reduce C, O and N contamination in mc-Si solar cells is at the directional solidification process, and (b) the costly specification of highly pure Si feedstock is unnecessary from a C, O and N perspective if a directional solidification process is used.

Type
Research Article
Copyright
Copyright © Materials Research Society 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Ghosh, M., Muller, A., Sontag, D.. Neuhaus, H., Bothe, K., and Schmidt, J., 21st PV SEC, Dresden, p. 1326 (2006).Google Scholar
2. Specification for Silicon Wafers for Use as Photovoltaic Solar Cells, SEMI International Standard M6-0707, (published by SEMI, San Jose, CA, www.semi.org org)Google Scholar
3. Test Method for Interstitial Oxygen Content of Silicon by Infrared Absorption with Short Baseline, SEMI International Standard MF1188-1105, published by SEMI, San Jose, CA, www.semi.org org)Google Scholar
4. Test Method for Measuring Oxygen Concentration in Heavily Doped Silicon Substrates by Secondary Ion Mass Spectrometry, SEMI International Standard MF1366-1107, published by SEMI, San Jose, CA, www.semi.org org)Google Scholar
5. Riepe, S., Reis, I. E., and Koch, W., “Solar Silicon Material Research Network SOLARFOCUS (Solarsilizium Forschungscluster),” 23rd PV SEC, (2008)Google Scholar
6. Test Method for Subsitutional Atomic Carbon Content of Silicon by Infrared Absorption, SEMI International Standard MF1391-1107, published by SEMI, San Jose, CA, www.semi.org org)Google Scholar
7. Kulkarni, Milind S., J. Crystal Growth 310, 324 (2008).Google Scholar
8. US Patent 6803576 - Analytical method to measure nitrogen concentration in single crystal silicon, October 12, 2004, (and references therein).Google Scholar
9. Test Method for Measuring Nitrogen Concentration in Silicon Substrates by Secondary Ion Mass Spectrometry, SEMI International Standard MF2139-1103, published by SEMI, San Jose, CA, www.semi.org org)Google Scholar
10. Secondary Ion Mass Spectrometry, A Practical Handbook for Depth Profiling and Bulk Impurity Analysis, edited by Wilson, Robert G., Stevie, Fred A., and Magee, Charles W., published by John Wiley & Sons, New York (1989).Google Scholar
11. Wang, L., Evans Analytical Group (private communication)Google Scholar