Crystallization of Si

Transcription

1 Crystallization of Si Summary/info: Date/Time *: 13 th November 2014 / 13:30 15:45 Central European Time (CET) UTC; (Brussels Time) Location: Sophi@Webinar *on line: Speakers: Dr. Mari Juel (SINTEF) Dr. Martin Bellmann (SINTEF) prof. Marisa Di Sabatino (NTNU) Agenda info Chairperson: MSc. John Atle Bones (SINTEF) FP7-PhotoVoltaic European Research Infrastructure Grant agreement no:

2 SOPHIA WEBINAR : Summary & Agenda: Crystallization of Si Crystallization is the lengthy natural process of formation of highly ordered structure of atoms that is today currently utilized in technology by artificially precipitating solid crystals from a solution, melt or gases to realize crystal structure. The growth of silicon Crystals is perhaps the the most important technological topics of the last decades the "silicon era" because It has been essential for the development of the electronic devices and solar cells. This short on line course introduces the main production technologies of monocrystalline silicon, how defects and impurities may be introduced from several sources, the mechanisms for formation of oxygen, one of the main impurities in Czochralski grown silicon, during crystal growth and wafer processing, the numerical simulation of crystal growth processes and correlated physical phenomena, as a powerful tool for the crystal grower, to improve the material properties and at the same time reducing production costs and time. Agenda: Click here

3 SOPHIA WEBINAR Crystallization of Si Agenda Topic Who 13:30-13:40 Welcome and Introduction John Atle Bones, SINTEF Franco Roca, ENEA 13:40-14:10 Topic 1: Silicon Crystallization and characterization techniques to assess the crystallization quality 14:10-14:20 Question and comments from the Webinar Audience All Marisa Di Sabatino (NTNU) 14:20-14:50 Topic 2: Formation of oxygen related defects in Cz-Si Dr. Mari Juel (SINTEF) :50-15:00 Question and comments from the Webinar Audience All 15: Topic Numerical simulation of crystallization processes in production of silicon for PV applications Martin P. Bellmann (SINTEF) 15:30-15:45 Question and comments and Final Discussion SINTEF/ENEA 3 info

4 Topic1: Silicon Crystallization and characterization techniques to assess the crystallization quality Abstract: Crystallization is one of the first steps during the silicon solar cells value chain. Before silicon solar cells are processed, a silicon ingot is grown either by monocrystalline or multicrystalline processes. During the process, defects may form and impurities may be introduced from several sources. The distribution of defects and impurities, as well as their interaction, is strongly affected by the crystallization process. Thus crystallization parameters play a key role in determining the final ingots quality. In this presentation, the effect of crystallization parameters on ingot quality and the techniques to assess them are reviewed. Speaker: Associate professor Marisa Di Sabatino (NTNU) Marisa Di Sabatino is associate professor at the Dept of Materials Science and Engineering at NTNU. She took her PhD in physical metallurgy at NTNU in Her main research areas are crystallization and characterization of silicon for solar cells, with main focus on glow discharge based analytical methods. She currently teaches several courses on silicon and photovoltaics.

5 Topic 2: Formation of oxygen related defects in Cz-Si Abstract: Oxygen is one of the main impurities in Czochralski grown silicon and can in the wrong state cause large problems and reduction in cell efficiency of silicon based solar cells. A large problem is that the recombination activity of the oxygen related defects often increases during cell processing, resulting in a solar cell with much lower cell efficiency than the expected from the as-grown minority carrier lifetime. One reason for this behaviour is believed to be that small oxygen particles can grow during high temperature solar cell processing steps and in this way change their state. The presentation will discuss the mechanisms for formation of oxygen related defects in monocrystalline silicon and show examples of which heat treatment and characterisation methods that can be used to identify them. Speaker: Dr. Mari Juel (SINTEF Materials and Chemistry) Mari Juel is a Research Scientist at SINTEF Materials and Chemistry, Department of New Energy Solutions. She received his PhD in Surface science at NTNU, Norway in Her research interests include the solidification and characterization of mono and multicrystalline silicon, with emphasize on formation of defects in silicon.

6 Topic 3: Numerical simulation of crystallization processes in production of silicon for PV applications Abstract: Crystal growth from the melt is the most common process which provides the basic crystalline silicon material for photovoltaic applications. Nowadays main production technologies for producing crystalline silicon are the Czochralski pulling technique, directional solidification and to some extend edge-defined film-fed growth. As crystal growth equipment and experimentation becomes more and more costly, little room remains for improvements by trial and error procedures. The numerical simulation of crystal growth processes and correlated physical phenomena provides a powerful tool for the crystal grower. Common goals are to improve the material properties at the micro- and macroscale resulting in higher solar cell efficiency, increase of crystal dimensions and at the same time reducing production costs and time. Speaker: Dr. Martin P. Bellmann (SINTEF Materials and Chemistry) Martin P. Bellmann is a Senior Research Scientist at SINTEF Materials and Chemistry, Department of Solar Cell Silicon. He received his PhD in Metallurgy of Nonferrous Metals and High-Pure Materials at the technical University Bergakademie Freiberg, Germany in His research interests include crystal growth and computational fluid dynamics. He represents Norway in the European Network of Crystal Growth (ENCG).