Programm Photovoltaik Ausgabe 2009 ... - Bundesamt für Energie BFE

Goals of the project
The global project goal is to allow for a lowering of the cost of solar electricity based on thin film silicon.
In particular, this projects aims at developing the processes and device structure for the future
generation of thin film silicon modules, based on amorphous Si or SiGe alloys, and microcrystalline
silicon. The objective of this “technology push” project is, hence to make the breakthroughs that will
allow in the medium to long term, ultra-low module production costs (< 1 €/Wp) at elevated efficiencies
(> 10 %), while ensuring a perfect module/layers reliability..
The major specific project milestones for the first year were:
� The improvement of low refractive index SiOx (n < 2.2) based intermediate reflectors (SOIR) suitable
for the fabrication of high efficiency micromorph solar cells.
� The fabrication of ZnO layers by LPCVD with an improved resistance against damp heat testing
� The development in large area reactors of microcrystalline cells at deposition rate higher than 0.6 nm/s
� The mastering of fabrication of tandem a-Si/a-Si cells in IMT R&D small areas reactors at 8.5%
efficiency in view of integration in triple junction devices.
� The comparison and integration of ZnO and SiOx as intermediate reflectors in high efficiency
micromorph cells with initial efficiencies > 13%
� The development of high-efficiency cell processes and structures for cells on flexible substrates
� The establishment of base recipes and procedures for the embedding of IMT samples.
In parallel a technological/technical effort had to be undertaken to
� Introduce process monitoring tools for plasma deposition
� Prepare a new laser set-up for the scribing of cells and modules
� Prepare a new set-up for monitoring of cell degradation in various configuration
� Ramp-up various new systems acquired in 2008.
Most of the projects milestones have been reached and are documented further.
Short project description
The project has four major research axes, and two transversal domains, described in Fig.1.
Fig.1: Summary of the major workpackages of the SFOE-IMT project 2008-2011
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New processes and device structures for the fabrication of high efficiency thin film silicon photovoltaic modules, C. Ballif, University of Neuchâtel
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