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Title: LSA large area silicon sheet task continuous Czochralski process development. Final report

Abstract

A commercial Czochralski crystal growing furnace was converted to a continuous growth facility by installation of a small, in-situ premelter with attendant silicon storage and transport mechanisms. The premelter was situated immediately over the primary melt and provided a molten silicon flow into the large crucible simultaneously as crystal was being grown. The key element in this continuous Czochralski process is the premelter and a substantial portion of the program involved its evolution into a workable design. The best arrangement tested was a vertical, cylindrical graphite heater containing a small fused quartz test tube liner from which the molten silicon flowed out the bottom. Approximately 83 cm of nominal 5-cm diameter crystal was grown with continuous melt addition furnished by the test tube premelter. High-perfection crystal was not obtained, however, due primarily to particulate contamination of the melt. A major contributor to the particulate problem was severe silicon oxide buildup on the premelter which would ultimately drop into the primary melt. Elimination of this oxide buildup will require extensive study and experimentation and the ultimate success of continuous Czochralski depends on a successful solution to this problem. Economic modeling of the continuous Czochralski process utilized the IPEG option of SAMICS.more » The influence of both crystal size and total furnace run size were examined. Results of these studies indicate that for 10-cm diameter crystal, 100-kg furnace runs of four or five crystals each are near optimal. Costs tend to asymptote at the 100-kg level so little additional cost improvement occurs at larger runs. For these conditions, crystal cost in equivalent wafer area of around $16/m/sup 2/ exclusive of polysilicon and slicing is obtained. Lower crystal costs can be obtained by growing larger diameter crystal in the 12 to 15-cm range.« less

Authors:
Publication Date:
Research Org.:
Texas Instruments, Inc., Dallas (USA)
Sponsoring Org.:
USDOE
OSTI Identifier:
5767125
Report Number(s):
DOE/JPL/954887-5
DOE Contract Number:  
NAS-7-100-954887
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; FURNACES; DESIGN; SILICON; CRYSTAL GROWTH; COST; CUTTING; CZOCHRALSKI METHOD; DIAGRAMS; ECONOMICS; FEASIBILITY STUDIES; IMPURITIES; MONOCRYSTALS; SIZE; CRYSTALS; ELEMENTS; MACHINING; SEMIMETALS; 140501* - Solar Energy Conversion- Photovoltaic Conversion; 360601 - Other Materials- Preparation & Manufacture

Citation Formats

Rea, S.N. LSA large area silicon sheet task continuous Czochralski process development. Final report. United States: N. p., 1979. Web. doi:10.2172/5767125.
Rea, S.N. LSA large area silicon sheet task continuous Czochralski process development. Final report. United States. doi:10.2172/5767125.
Rea, S.N. Thu . "LSA large area silicon sheet task continuous Czochralski process development. Final report". United States. doi:10.2172/5767125. https://www.osti.gov/servlets/purl/5767125.
@article{osti_5767125,
title = {LSA large area silicon sheet task continuous Czochralski process development. Final report},
author = {Rea, S.N.},
abstractNote = {A commercial Czochralski crystal growing furnace was converted to a continuous growth facility by installation of a small, in-situ premelter with attendant silicon storage and transport mechanisms. The premelter was situated immediately over the primary melt and provided a molten silicon flow into the large crucible simultaneously as crystal was being grown. The key element in this continuous Czochralski process is the premelter and a substantial portion of the program involved its evolution into a workable design. The best arrangement tested was a vertical, cylindrical graphite heater containing a small fused quartz test tube liner from which the molten silicon flowed out the bottom. Approximately 83 cm of nominal 5-cm diameter crystal was grown with continuous melt addition furnished by the test tube premelter. High-perfection crystal was not obtained, however, due primarily to particulate contamination of the melt. A major contributor to the particulate problem was severe silicon oxide buildup on the premelter which would ultimately drop into the primary melt. Elimination of this oxide buildup will require extensive study and experimentation and the ultimate success of continuous Czochralski depends on a successful solution to this problem. Economic modeling of the continuous Czochralski process utilized the IPEG option of SAMICS. The influence of both crystal size and total furnace run size were examined. Results of these studies indicate that for 10-cm diameter crystal, 100-kg furnace runs of four or five crystals each are near optimal. Costs tend to asymptote at the 100-kg level so little additional cost improvement occurs at larger runs. For these conditions, crystal cost in equivalent wafer area of around $16/m/sup 2/ exclusive of polysilicon and slicing is obtained. Lower crystal costs can be obtained by growing larger diameter crystal in the 12 to 15-cm range.},
doi = {10.2172/5767125},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1979},
month = {2}
}