IMEC

The Interuniversity Microelectronics Centre (imec) is one of the largest independent R&D centers worldwide in the field of nano-electronics. Imec has nearly 2000 employees and is known for its broad coverage of nano-electronic technologies, its balance of basic research and application-oriented research, its unique infrastructure and its independent character.
The PV department within imec performs research on new materials, concepts and pathways for photovoltaic devices as a renewable energy source and as an enabling technology to ensure energy autonomy. Imec focuses on crystalline-silicon wafer-based solar cells, thin-film solar cells (chalcopyrites, kesterites) and organic and perovskite solar cells. With its partners, imec works on improving the efficiency, the industrial manufacturability, and the cost reduction of a number of advanced technologies for the coming decade. Imec’s PV department is a worldwide-acknowledged leader in the development of industrially relevant pilot processes for silicon solar cells on thin silicon substrates.
The crystalline-Si solar cell group of IMEC is involved in this project. This group uses a dedicated pilot line for crystalline silicon cells. Research in this group covers both short-term activities such as process improvements that can be immediately applied in the industry, and medium-term activities such as the work performed within this project.

 Role in the Project

Imec is working within this project on the development of 40-micron thin foils based on porous silicon and epitaxial thickening. For this purpose, imec is developing within WP6 large-area porous-silicon layers that act simultaneously as seed layers for silicon epitaxy and as detachment layers for separating the epitaxial silicon foils from the parent substrate. The main goal is to achieve high-quality epitaxial silicon foils exhibiting large minority carrier lifetimes in combination with close to 100% detachment yield of the silicon foils from their parent substrate. Imec is also working on the demonstration of the re-usability of the parent substrate to produce multiple epitaxial foils from the same silicon substrate. Simultaneously we are developing new processes within WP7 to make such thin layers into highly-efficient solar cells with a high yield.  Here the focus is on achieving sufficient light confinement within the epitaxial layers and developing processes for junction formation, passivation and metallization that are compatible with the use of ultra-thin epitaxial silicon foils.