245
Development
of Solar Grade (SoG) Silicon--Crystal
Systems, Inc., 27 Congress Street, Salem,
MA 01970-5597; 978-745-0088, www.crystalsystems.com
Dr.
David B. Joyce, Principal Investigator, djoyce@crystalsystems.com
Dr.
Chandra P. Khattak, Business Official, chandra@crystalsystems.com
DOE
Grant No. DE-FG02-04ER83928
Amount:
$99,928
The
continued rapid growth of the photovoltaic (PV) industry (43.5% growth in 2002)
is limited by the availability of low-cost solar-grade (SoG) silicon feedstock
in large quantities. It is estimated
that current sources of SoG silicon (scraps and surplus capacity from the
semiconductor industry) will not meet the demand by 2005.
This project will develop low-cost technology for SoG silicon production
by upgrading metallurgical-grade (MG) silicon, which is commercially produced in
large quantities worldwide. Additives
to the MG silicon will remove B, P, and Al impurities, and other impurities will
be removed by directional solidification. The
technology will be integrated with MG silicon production for commercialization.
In Phase I, additions
will be made to the low-purity MG silicon, which will be melted and
directionally solidified. The
additives will form compounds with high segregation coefficient impurities,
which will be separated, volatilized, or segregated, leaving behind the higher
purity silicon that can be used as SoG silicon feedstock.
Commercial
Applications and Other Benefits
as described by the awardee: The
technology should provide SoG silicon for the PV community, thereby addressing
the shortage that is expected by 2005. This
feedstock could also be used for some devices in the semiconductor industry.