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Title: A method for determining average damage depth of sawn crystalline silicon wafers

The depth of surface damage (or simply, damage) in crystalline silicon wafers, caused by wire sawing of ingots, is determined by performing a series of minority carrier lifetime (MCLT) measurements. Samples are sequentially etched to remove thin layers from each surface and MCLT is measured after each etch step. The thickness-removed (..delta..t) at which the lifetime reaches a peak value corresponds to the damage depth. This technique also allows the damage to be quantified in terms of effective surface recombination velocity (Seff). To accomplish this, the MCLT data are converted into an Seff vs ..delta..t plot, which represents a quantitative distribution of the degree of damage within the surface layer. We describe a wafer preparation procedure to attain reproducible etching and MCLT measurement results. We also describe important characteristics of an etchant used for controllably removing thin layers from the wafer surfaces. Some typical results showing changes in the MCLT vs ..delta..t plots for different cutting parameters are given.
Authors:
 [1] ;  [2] ;  [2]
  1. National Renewable Energy Laboratory, Golden, Colorado 80401, USA
  2. National Renewable Energy Laboratory, Golden, Colorado 80401, USA; New Jersey Institute of Technology, Newark, New Jersey 07102, USA
Publication Date:
OSTI Identifier:
1248799
Report Number(s):
NREL/JA--5J00-66320
Journal ID: ISSN 0034-6748; RSINAK
DOE Contract Number:
AC36-08GO28308
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 87; Journal Issue: 4; Related Information: Review of Scientific Instruments
Publisher:
American Institute of Physics (AIP)
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE etching; dislocations; electron hole recombination; passivation; slurries