Arriving at well-founded specifications for SoG Si feedstock

Workshop on November 13th & 14th, 2008 in Amsterdam, the Netherlands.

The workshop on Solar Grade Silicon feedstock specifications was very successful, with approximately 70 active participants. At the end of the workshop, potential specification requirements were discussed, and will be further detailed in the proceedings of the workshop.

Aim: to discuss and agree upon solar grade silicon feedstock specifications.
How: exchanging results, views and opinions on solar grade silicon among participants from research institutes, universities and industry. Topics included the impact of solar grade silicon feedstock properties (impurities, dopants, shape, etc.), and other materials (e.g. crucible, coating) on wafer and cell levels. 

Background
At the moment, the PhotoVoltaic (PV) industry is facing a shortage in silicon feedstock. This has led to a steady introduction of silicon via the non-conventional route. Also, it is expected that Solar Grade Silicon (SoG Si) made through the direct or metallurgical purification route will become available on the market soon. Therefore, the PV industry should address the question how cell parameters are affected by, and cell processes can be best adapted for, less pure material. These were the main topics of this workshop. The workshop was organized in the framework of the EU-funded project CrystalClear. A major aim in this project is to gain better scientific understanding on solar grade silicon.

Workshop programme
Based on the abstracts received, the organizing committee outlined the workshop program. Main program topics were:
- Transition metals
- Dopants (B, P, Al)
- Carbon, oxygen, nitrogen & light induced degradation
- How to get the best out of your feedstock?
- How will Si-producers cope with the challenges?

Contribution
All participants contributed to the workshop by submitting an abstract that have been evaluated by the Scientific Committee. The Scientific Committee consisted of:
- Bruno Ceccaroli, REC
- Gianluca Coletti, ECN
- Giso Hahn, University of Konstanz
- Stephan Riepe, Fraunhofer ISE
- Karsten Wambach, Deutsche Solar

Workshop Chairman:
Wim Sinke, Coordinator CrystalClear.

Arrangements:
The workshop took place at the Beurs van Berlage, Beursplein 1-3 in the city centre of Amsterdam. In the evening of Thursday November 13th, a diner was organized.

Further information:
Gianluca Coletti, SP1 Leader CrystalClear
+31 224 56 4937
SP1WORKSHOP@ecn.nl