FoXy-DEVELOPMENT OF SOLAR-GRADE SILICON FEEDSTOCK FOR CRYSTALLINE WAFERS AND CELLS BY PURIFICATION AND CRYSTALLISATION M. Di Sabatino 1 , E.J. Øvrelid 1 , R. Kopecek 2 , S. Binetti 3 , V.D. Mihailetchi 4* , L. Geerligs 4 , A.N. Værnes 1 1 SINTEF Materials and Chemistry, 7465 Trondheim, NORWAY 2 ISC, Konstanz, GERMANY 3 UNIMIB, Milan, ITALY 4 ECN, Petten, THE NETHERLANDS     * Presently at ISC, Konstanz, GERMANY ABSTRACT This work reports on the results obtained in the EU project FoXy (contract nr SES6-019811). FoXy has been carried out in the 6 th Framework Program in the Sustainable Energy Systems. It consists of a Europe-wide consortium of small and medium size enterprises, research institutes and universities. The project has aimed at developing cleaning and crystallisation processes for metallurgical SoG-Si feedstock, optimize associated cell and module processes, and set parameters for these types of feedstock. The major goals of the project have been: (i) achieve a significant cost reduction through more efficient cleaning processes for raw materials, (ii) secure high volume production of SoG-Si, (iii) develop recycling techniques for end-of-life products, (iv) shorten the energy payback time significantly, (v) manufacture wafers on a large-scale industrial production line 150x150mm 2 aiming at 16-17% cell efficiency with increased yield. This work summarizes the highlight results of this three-year project. Keywords: Silicon, Feedstock, Solar cell, Efficiency INTRODUCTION FoXy is a R&D project which aims at developing refining and crystallisation processes for metallurgical SoG-Si feedstock, optimise associated cell and module processes, and set parameters for these types of feedstock. Under the realistic assumption that Si-wafer based PV modules will dominate the market in the coming decade, the FoXy partnership has focused on the need of the PV market for low price and high quality solar grade silicon (SoG-Si) feedstock by: 1. Further developing and optimising refining, purification, and crystallisation processes for metallurgical SoG-Si feedstock, as well as for recycled n-type electronic grade Si. 2. Optimising associated cell and module processes. 3. Setting input criteria for metallurgical and electronic n- type silicon to be used as raw materials for SoG-Si feedstock. 4. Transferring the technology from laboratory to industrial pilot tests. The overall objectives of the FoXy project have been: 1. Achieve a significant cost reduction (down to 15€ per kg) through more efficient cleaning processes for raw materials. 2. Secure high volume production of SoG-Si. 3. Develop recycling techniques for end-of-life products. 4. Shorten energy payback time to six months. 5. Manufacture wafers on a large-scale industrial production line 150x150mm 2 aiming at 16-17% cell-efficiency with increased yield. The achievement of these aims allows the PV industry to strengthen its position on the world market and fulfil the EU policy targets. The project has had a total budget of 4.7 M€, of which 2.7 M€ has been the requested EC contribution. A schematic structure of the project is shown in Figure 1. The project has been subdivided into the following tasks: WP1 - Feedstock via direct route WP2 -Refining of highly doped feedstock and production of n-type ingots WP3 -Electrochemical refining of metallurgical feedstock WP4 -Material characterisation WP5 -Cell process optimisation WP6 -Modules and Recycling ‘end of life’ WP7 -Integration &Exploitation SINTEF has been coordinator for the project. The FoXy consortium has consisted of 11 partners, divided in:  Industry partners Deutsche Solar (DE), Isofoton (ES), FESIL (NO), PILLAR (UA), SUNERGY (NL), ScanArc (SE)  Universities NTNU (NO), UNIMIB (IT)  Research Institutes ECN (NL), ISC (DE), SINTEF (NO) The FoXy project started on January 1 st , 2006 and has been running for 36 months. During this period, the project has achieved important results. Among these, new feedstock processing routes have been investigated, refining techniques have been developed and a new passivation process has been patented, etc. In this work, we present and summarize some of the major results from the subprojects WP4 and WP5. 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany 1823