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Title: Surface characteristics and damage distributions of diamond wire sawn wafers for silicon solar cells

Abstract

This paper describes surface characteristics, in terms of its morphology, roughness and near-surface damage of Si wafers cut by diamond wire sawing (DWS) of Si ingots under different cutting conditions. Diamond wire sawn Si wafers exhibit nearly-periodic surface features of different spatial wavelengths, which correspond to kinematics of various movements during wafering, such as ingot feed, wire reciprocation, and wire snap. The surface damage occurs in the form of frozen-in dislocations, phase changes, and microcracks. The in-depth damage was determined by conventional methods such as TEM, SEM and angle-polishing/defect-etching. However, because these methods only provide local information, we have also applied a new technique that determines average damage depth over a large area. This technique uses sequential measurement of the minority carrier lifetime after etching thin layers from the surfaces. The lateral spatial damage variations, which seem to be mainly related to wire reciprocation process, were observed by photoluminescence and minority carrier lifetime mapping. Our results show a strong correlation of damage depth on the diamond grit size and wire usage.

Authors:
; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
Contributing Org.:
1 National Renewable Energy Laboratory, Golden, CO 80401, USA
OSTI Identifier:
1273068
Report Number(s):
NREL/JA-5J00-66329
Journal ID: ISSN 2372-0484
DOE Contract Number:  
AC36-08GO28308
Resource Type:
Journal Article
Journal Name:
AIMS Materials Science (Online)
Additional Journal Information:
Journal Volume: 3; Journal Issue: 2; Journal ID: ISSN 2372-0484
Publisher:
AIMS Press
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; diamond wire sawing; sawing damage; lifetime

Citation Formats

Sopori, Bhushan, Devayajanam, Srinivas, and Basnyat, Prakash. Surface characteristics and damage distributions of diamond wire sawn wafers for silicon solar cells. United States: N. p., 2016. Web. doi:10.3934/matersci.2016.2.669.
Sopori, Bhushan, Devayajanam, Srinivas, & Basnyat, Prakash. Surface characteristics and damage distributions of diamond wire sawn wafers for silicon solar cells. United States. https://doi.org/10.3934/matersci.2016.2.669
Sopori, Bhushan, Devayajanam, Srinivas, and Basnyat, Prakash. 2016. "Surface characteristics and damage distributions of diamond wire sawn wafers for silicon solar cells". United States. https://doi.org/10.3934/matersci.2016.2.669.
@article{osti_1273068,
title = {Surface characteristics and damage distributions of diamond wire sawn wafers for silicon solar cells},
author = {Sopori, Bhushan and Devayajanam, Srinivas and Basnyat, Prakash},
abstractNote = {This paper describes surface characteristics, in terms of its morphology, roughness and near-surface damage of Si wafers cut by diamond wire sawing (DWS) of Si ingots under different cutting conditions. Diamond wire sawn Si wafers exhibit nearly-periodic surface features of different spatial wavelengths, which correspond to kinematics of various movements during wafering, such as ingot feed, wire reciprocation, and wire snap. The surface damage occurs in the form of frozen-in dislocations, phase changes, and microcracks. The in-depth damage was determined by conventional methods such as TEM, SEM and angle-polishing/defect-etching. However, because these methods only provide local information, we have also applied a new technique that determines average damage depth over a large area. This technique uses sequential measurement of the minority carrier lifetime after etching thin layers from the surfaces. The lateral spatial damage variations, which seem to be mainly related to wire reciprocation process, were observed by photoluminescence and minority carrier lifetime mapping. Our results show a strong correlation of damage depth on the diamond grit size and wire usage.},
doi = {10.3934/matersci.2016.2.669},
url = {https://www.osti.gov/biblio/1273068}, journal = {AIMS Materials Science (Online)},
issn = {2372-0484},
number = 2,
volume = 3,
place = {United States},
year = {Fri Jan 01 00:00:00 EST 2016},
month = {Fri Jan 01 00:00:00 EST 2016}
}