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Title: Carbon elimination from silicon kerf: Thermogravimetric analysis and mechanistic considerations

40% of ultrapure silicon is lost as kerf during slicing to produce wafers. Currently, kerf is not recycled due to engineering challenges and costs associated with removing its abundant impurities. Carbon left behind from the lubricant remains as one of the most difficult contaminants to remove in kerf without significant silicon oxidation. The present work enables to better understand the mechanism of carbon elimination in kerf which can aid the design of better processes for kef recycling and low cost photovoltaics. In this paper, we studied the kinetics of carbon elimination from silicon kerf in two atmospheres: air and N 2, under a regime of no-diffusion-limitation. Here, we report the apparent activation energy in both atmospheres using three methods: Kissinger, and two isoconversional approaches. In both atmospheres, a bimodal apparent activation energy is observed, suggesting a two stage process. Furthermore, a reaction mechanism is proposed in which (a) C-C and C-O bond cleavage reactions occur in parallel with polymer formation; (b) at higher temperatures, this polymer fully degrades in air but leaves a tarry residue in N 2 that accounts for about 12% of the initial total carbon.
Authors:
 [1] ;  [1] ;  [2] ;  [1]
  1. Washington Univ., St. Louis, MO (United States). Dept. of Energy, Environmental and Chemical Engineering
  2. Saint Louis Univ., MO (United States). Parks College Dept. of Chemistry
Publication Date:
Grant/Contract Number:
AC36-08GO28308
Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Research Org:
Alliance for Sustainable Energy, LLC,Lakewood, CO (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
Country of Publication:
United States
Language:
English
Subject:
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
OSTI Identifier:
1347387

Vazquez-Pufleau, Miguel, Chadha, Tandeep S., Yablonsky, Gregory, and Biswas, Pratim. Carbon elimination from silicon kerf: Thermogravimetric analysis and mechanistic considerations. United States: N. p., Web. doi:10.1038/srep40535.
Vazquez-Pufleau, Miguel, Chadha, Tandeep S., Yablonsky, Gregory, & Biswas, Pratim. Carbon elimination from silicon kerf: Thermogravimetric analysis and mechanistic considerations. United States. doi:10.1038/srep40535.
Vazquez-Pufleau, Miguel, Chadha, Tandeep S., Yablonsky, Gregory, and Biswas, Pratim. 2017. "Carbon elimination from silicon kerf: Thermogravimetric analysis and mechanistic considerations". United States. doi:10.1038/srep40535. https://www.osti.gov/servlets/purl/1347387.
@article{osti_1347387,
title = {Carbon elimination from silicon kerf: Thermogravimetric analysis and mechanistic considerations},
author = {Vazquez-Pufleau, Miguel and Chadha, Tandeep S. and Yablonsky, Gregory and Biswas, Pratim},
abstractNote = {40% of ultrapure silicon is lost as kerf during slicing to produce wafers. Currently, kerf is not recycled due to engineering challenges and costs associated with removing its abundant impurities. Carbon left behind from the lubricant remains as one of the most difficult contaminants to remove in kerf without significant silicon oxidation. The present work enables to better understand the mechanism of carbon elimination in kerf which can aid the design of better processes for kef recycling and low cost photovoltaics. In this paper, we studied the kinetics of carbon elimination from silicon kerf in two atmospheres: air and N2, under a regime of no-diffusion-limitation. Here, we report the apparent activation energy in both atmospheres using three methods: Kissinger, and two isoconversional approaches. In both atmospheres, a bimodal apparent activation energy is observed, suggesting a two stage process. Furthermore, a reaction mechanism is proposed in which (a) C-C and C-O bond cleavage reactions occur in parallel with polymer formation; (b) at higher temperatures, this polymer fully degrades in air but leaves a tarry residue in N2 that accounts for about 12% of the initial total carbon.},
doi = {10.1038/srep40535},
journal = {Scientific Reports},
number = ,
volume = 7,
place = {United States},
year = {2017},
month = {1}
}