Epitaxy, Si-Foils and SiC Deposition

R&D Services

Our R&D services comprise:

c-Si Thin-Film on Foreign Substrates

CVD and Epitaxy

Kerff-Less Wafering

One specialist field within crystalline silicon solar cells is that of crystalline Si thin-film solar cells (CSiTF solar cells). Here, the desirable qualities of wafer and thin-film solar cells are combined: high efficiency without degradation and low levels of silicon consumption.

The manufacturing concepts we are employing at Fraunhofer ISE use epitaxy or recrystallization to produce the silicon layers in CSiTF cells. These layers are either fabricated directly on inexpensive substrates (e.g. low-grade silicon wafers or ceramics), or are attached to suitable substrates using transfer technology after their production. The substrate-layer stacks thus created are called wafer equivalents. Customized functional coatings, such as those made from silicon carbide, are being developed for different wafer equivalents. Furthermore, cell and module concepts that are tailored to these wafer equivalents are also the subject of our research and development work; for example module-scale, integrated cell connection or nanotextures.

These research topics all involve testing for basic operating functions and development that promotes high throughput and low manufacturing costs.

In addition, we not only develop technology for CSiTF solar cell and module concepts, but also generate expert knowledge and file patents that are available for licensing.

We also offer the following services:

  • Encapsulation and infiltration with µc-Si/µc-SiC
  • Si epitaxy (n-, p-doped)
  • Porous silicon formation, reorganization and lift-off
  • Amorphous SiC deposition
  • Annealing (H2, Ar, N2 atmospheres)
  • Crystallization (solid phase and liquid phase zone melting)
  • Dopant profile characterisation by Spreading Resistance Profiling  (SRP) and Electrochemical Capacitance-Voltage (ECV) measurements
  • X-Ray diffraction (XRD;Glacing-Incidence-XRD, rocking curve and X-ray reflectometry)
  • Laser marking of wafered ingots
  • Laser cutting of silicon in a variety of shapes and formats
  • Grinding/polishing of cross-sections and beveled sections for sample characterisation and other purposes
  • Cleaning/diffusion/oxidization of materials with diverse impurity classifications and greatly varying dimensions, performed in systems divided into cleanliness classes
  • Plasma texturing
  • Remote plasma hydrogen passivation (RPHP) – passivating Si bulk defects by in-diffusion of atomic hydrogen

Selected Research Projects



Development of Nano-Porous Silicon Layers in an Inline Process



High-Efficiency III-V Multi-Junction Solar Cells on Silicon



Nanoimprint Lithography for Extremely Fine Solar Cell Structures


Current publications of the research topic Epitaxy, Si-Foils and SiC Deposition:

YearTitle/AuthorDocument Type
2018Challenges for Silicon Photovoltaics. Next steps in manufacturing and advanced technologies: Presentation held at PVCellTech, Penang, Malaysia, 14th March 2018
Bett, A.W.
2018Defects in Epitaxially Grown Silicon Wafers Causing Lifetime Patterns
Drießen, M.; Beu, P.; Heinz, F.D.; Fehrenbach, T.; Gust, E.; Schindler, F.; Janz, S.
Conference Paper
2018Optimization of inline processes for the production of freestanding epitaxially grown thin films for solar cells
Ivanov, Alexey; Sorgenfrei, R.; Gust, Elke; Barth, Philipp; Nieuwenhuysen, Kris van; Kühnhold-Pospischil, Saskia; Riepe, Stephan; Janz, Stefan
Conference Paper
2018Rapid vapor-phase direct doping for high-efficiency solar cells
Kühnhold-Pospischil, Saskia; Steinhauser, Bernd; Richter, Armin; Gust, Elke; Janz, Stefan
Journal Article
2018Trends in Solar Electricity: Presentation held at EuroSun, 12th International Conference on Solar Energy for Buildings and Industry 2018, Rapperswil, Switzerland, September 11th, 2018
Bett, A.W.
201720% efficient solar cells fabricated from epitaxially grown and freestanding n-type wafers
Milenkovic, N.; Driessen, M.; Steinhauser, B.; Benick, J.; Lindekugel, S.; Hermle, M.; Janz, S.; Reber, S.
Journal Article
2017Monolithic two-terminal III-V//Si triple-junction solar cells with 30.2% efficiency under 1-Sun AM1.5g
Cariou, R.; Benick, J.; Beutel, P.; Razek, N.; Flötgen, C.; Hermle, M.; Lackner, D.; Glunz, S.W.; Bett, A.W.; Wimplinger, M.; Dimroth, F.
Journal Article
2017Origin and impact of crystallographic defects in epitaxially grown Si wafers
Janz, S.; Amiri, D.; Gust, E.; Kühnhold-Pospischil, S.; Riepe, S.; Heinz, F.; Drießen, M.
Conference Paper
2016Degradation of silicon wafers at high temperatures for epitaxial deposition
Rachow, T.; Reber, S.; Janz, S.; Knapp, M.; Milenkovic, N.
Journal Article
2016Epitaxial N-type silicon solar cells with 20% efficiency
Milenkovic, N.; Drießen, M.; Steinhauser, B.; Benick, J.; Lindekugel, S.; Hermle, M.; Janz, S.; Reber, S.
Conference Paper
2016Forschungstrends bei den Photovoltaik-Technologien: Vortrag gehalten auf der FVEE-Jahrestagung 2016, Berlin, Germany, 2. und 3. November 2016
Rech, B.; Albrecht, S.; Brendel, R.; Peibst, R.; Schmidt, J.; Glunz, S.W.; Bett, A.; Rau, U.; Kirchartz, T.; Camus, C.; Egelhaaf, H.-J.; Baumann, A.; Powalla, M.
2016Solar cells with 20% efficiency and lifetime evaluation of epitaxial wafers
Drießen, M.; Amiri, D.; Milenkovic, N.; Steinhauser, B.; Lindekugel, S.; Benick, J.; Reber, S.; Janz, S.
Journal Article
2015Development of integrated interconnected crystalline silicon thin film solar cells
Pavlovic, R.; Lindekugel, S.; Janz, S.; Reber, S.
Journal Article
2015Development of multicrystalline silicon for 20 % efficient n-Type solar cells
Riepe, S.; Krenckel, P.; Schindler, F.; Schmid, C.; Strauch, T.; Benick, J.; Schubert, M.C.
Conference Paper
2015Lifetime limitations of epitaxial P- and N-type Si foils
Janz, S.; Milenkovic, N.; Drießen, M.; Reber, S.
Conference Paper
2015N-type and P-type silicon foils fabricated in a quasi-inline EPI reactor with bulk lifetimes exceeding 500 µs
Janz, S.; Milenkovic, N.; Drießen, M.; Reber, S.
Conference Paper
2015Porous silicon reorganization: Influence on the structure, surface roughness and strain
Milenkovic, N.; Drießen, M.; Weiss, C.; Janz, S.
Journal Article
2015Solarenergie zur Stromerzeugung
Kiefer, K.
Book Article
2014Determination of the minority carrier lifetime in crystalline silicon thin-film material
Walter, D.; Rosenits, P.; Berger, B.; Reber, S.; Warta, W.
Journal Article
2014Epitaxial n- and p-Type Emitters for High Efficiency Solar Cell Concepts
Rachow, T.; Milenkovic, N.; Heinz, F.; Steinhauser, B.; Janz, S.; Reber, S.
Journal Article
2014The EU Project R2M-Si on roll to module processed crystalline silicon thin-films
Lindekugel, S.; Therheiden, B.; Pavlovic, R.; Nieuwenhuysen, K. van; Petterson, T.; Astrova, E.; Straboni, A.; Kühnlein, H.H.; Reber, S.
Conference Paper
2014Process control and defect analysis for crystalline silicon thin films for photovoltaic applications by the means of electrical and spectroscopic microcharacterization tools
Breitwieser, M.; Heinz, F.; Rachow, T.; Kasemann, M.; Janz, S.; Warta, W.; Schubert, M.C.
Journal Article
2014Reorganization of Porous Silicon. Effect on Epitaxial Layer Quality and Detachment
Milenkovic, N.; Drießen, M.; Gust, E.; Janz, S.; Reber, S.
Journal Article
2013Comparison between experimental results and CFD model calculations for high-throughout continuous silicon chemical vapour deposition epitaxy
Pócza, D.; Schillinger, N.; Barth, P.; Krogull, D.; Arnold, M.; Keller, M.; Reber, S.
Conference Paper
2013Defect annealing processes for polycrystalline silicon thin-film solar cells
Steffens, S.; Becker, C.; Zollondz, J.-H.; Chowdhury, A.; Slaoui, A.; Lindekugel, S.; Schubert, U.; Evans, R.; Rech, B.
Journal Article
2013Epitaxial wafer equivalent solar cells with overgrown SiO2 layer and varying doping profile to reduce the influence of defects
Drießen, M.; Reber, S.
Conference Paper
2013HCl gas gettering of low-cost silicon
Hampel, J.; Ehrenreich, P.; Wiehl, N.; Kratz, J.V.; Reber, S.
Journal Article
2013IntegRex - process development of a module interconnection concept for thin crystalline silicon films
Pavlovic, R.; Lindekugel, S.; Janz, S.; Reber, S.
Conference Paper
2013Lifetime measurements of crystalline silicon thin films by microwave photo conductance decay
Rachow, T.; Flatten, L.; Schillinger, K.; Janz, S.; Reber, S.
Conference Paper
2013Nanoimprinted diffraction gratings for crystalline silicon solar cells: Implementation, characterization and simulation
Mellor, A.; Hauser, H.; Wellens, C.; Benick, J.; Eisenlohr, J.; Peters, M.; Guttowski, A.; Tobias, I.; Marti, A.; Luque, A.; Bläsi, B.
Journal Article
2013Process optimization and solar cell results of ConCVD epitaxial layers
Keller, M.; Reber, S.; Schillinger, N.; Arnold, M.; Krogull, D.; Heermann, S.
Conference Paper
2013Recrystallized silicon thin-film solar cells on zircon ceramics
Schillinger, K.; Janz, S.; Reber, S.
Conference Paper
This publication list has been generated from the publication database Fraunhofer-Publica.