Flash Lamp Annealing

Alternatively: pulsed light, photonic sintering, photonic curing

Flash lamp annealing

Flash lamp annealing (FLA), also known as pulsed light, photonic sintering or photonic curing, is a thermal post-treatment process in which surfaces are heated in a fraction of a second. Typical treatment times range from a few microseconds to a few milliseconds. The surface is treated with one or more high-energy flashes from a flash lamp. This allows changes in the material properties to be achieved without thermally stressing the underlying substrate. This makes it possible to use temperature-sensitive substrates.

Compared to conventional annealing in an oven, flash lamp annealing is faster, more energy-efficient and involves a significantly lower system footprint. This ultra-short tempering process is therefore characterized by its low cost intensity. Furthermore, it causes hardly any thermal stresses in the substrate and diffusion processes are reduced due to the short process duration.


Tempering processes are necessary in semiconductor and thin-film technology, for example to specifically modify electrical and optical material properties as well as crystal and phase properties depending on the area of application. Printing and sintering processes also benefit from annealing processes, as densification and cross-linking effects occur here.

At Fraunhofer FEP, we offer our expertise in the treatment of different surfaces and substrates. These can include transparent conductive oxides, optical thin films, thin-film electronics and much more.

Application examples:

  • Treatment of layer systems (e.g. lowE, optical filter, ...)
  •     (Re-)crystallization of thin films (e.g. ITO, IZO, ZnO:Al, TiO2 ...)
  •     Thin-film electronics (display, photovoltaics, semiconductor doping, TFT, TTFT, ...)
  •     Printable electronics / circuits (on temperature-sensitive substrates)


We have an in-line flash lamp module for dynamic annealing of samples with a maximum size of 1200 × 600 mm² and a maximum flash power of 50 J/cm². The module is integrated into the ILA 900 vacuum coating system and thus enables flash lamp tempering of large surfaces in combination with PVD processes. In addition to annealing in a vacuum, FLA treatment in air, inert or reactive atmosphere is also possible. This gives us the unique opportunity to carry out tests dynamically, inline, in combination with PVD processes, over a large area in a large energy density range under industrial conditions.

Furthermore, we have a smaller test stand in which annealing tests can be carried out to clarify fundamental questions of principle. It is also possible to carry out basic investigations into the FLA process and hardware here.


Lamp Xe lamp with 750 mm arc length
Max. power 80 kW
Pulse duration 1 ... 10 ms
Energy density 1 ... 50 J/cm²
Max. substrate dimensions 1200 × 600 mm²
Substrate transport vertival in-line
Atmospheres in-vacuo an der ILA 900

In-line vacuum system ILA 900 / FLA test stand

ILA 900 in-line vacuum system
FLA test stand
  • Investigation of FLA in combination with PVD coating on an industrial pilot scale
  • Investigation of FLA of sample series (static or inline)
  • Basic technological investigations into the FLA process

Our services

  • Research and development of thin-film processes with tempering by FLA
  • Feasibility studies
  • Tempering of small series
  • Development of FLA processes for functional thin films or layer stacks on a pilot scale
  • Development of concepts, technology transfer and process integration

Highly productive low temperature annealing of ITO coatings



  • Annealing of ITO coatings
  • High throughput inline process
  • Low temperature process


  • PVD coating of ITO thin films adapted to flash lamp annealing
  • In-line flash lamp annealing

Resistivity: 16 Ω ± 10%
Size: 600 × 1200 mm2
Transport speed 0,50 m/min --> 2,5 min


Flash Lamp Annealing of Vanadium oxide VOx



Annealing of VOX to thermochromic VO2

  • Tetragonal VO2 on ultra-thin glass
  • No seed layer


  • HiPIMS coating in combination with flash lamp post annealing in-vacuo

Flash Lamp Annealing on Flexible Materials



Annealing of transparent conductors

  • Enhancement of optical or electrical properties


  • In-line PVD coating of ITO thin films adapted to flash lamp annealing
  • In-line flash lamp annealing

Highly productive low temperature nano-particle synthesis



Synthesis of nano-particles

  • High throughput inline process
  • Low temperature process


  • PVD coating in combination with inline flash lamp annealing in vacuo


  • Biozide surfaces
  • Plasmonic coatings


Transport speed 0.40 m/min
Substrate temperature < 120°C
Nano-particle size and distribution adjustable

Funding references

Innovative pulse modulation for the operation of high power flash lamps.
Funded by: Saxon State Ministry of Economics, Labor and Transport
Funding reference: 100349243
Duration: 01.09.2018 – 30.11.2021

As part of the funded InnoFlash project (sponsor: Saxon State Ministry of Economics, Labor and Transport | project number 100349243/3698), flash lamp temperature control for large-scale applications is being investigated and further developed.


  • T. Preußner, M. Neubert, U. Reichmann, K. Täschner, J. Neidhardt: „Recent developments in inline flash lamp annealing for ultra-fast thermal annealing of large substrate areas“, Conference on Plasma and Surface Engineering, Erfurt, September 2022.
  • J. Neidhardt, T. Preußner: „In-vacuo Integration einer Blitzlampentemperstation in eine Durchlaufbeschichtungsanlage – form Lab to Fab“, Blitzlab, Helmholtz-Zentrum Dresden-Rossendorf, April 2022.
  • T. Preußner, K. Täschner, M. Neubert, M. Junghähnel, W. Langgemach, U. Reichmann: „Recent developments in inline flash lamp annealing of ultra-fast thermal annealing of large substrat areas“, LOPEC 21, March 2021.
  • S. Weller: „Blitzlampentemperung von transparenten leitfähigen Oxidschichten”, Dissertation, Technische Universität Bergakademie Freiberg, Fakultät für Werkstoffwissenschaft, 2018.
  • W. Walther: „Untersuchung des Einflusses der Blitzlampentemperung auf die Eigenschaften verschiedener Gläser und Dünnschicht-Glas-Systeme“, Diplomarbeit, Technische Universität Bergakademie Freiberg, Fakultät für Maschinenbau, Verfahrens- und Energietechnik, 2018.
  • M. Junghähnel, J. Westphalen: „Processing on Flexible Glass – Challenges and Opportunities“, SVC Bulletin Fall/Winter, S. 31-39, 2017.
  •  J. Westphalen, M. Junghähnel, G. Lorenz, F. Naumann: „Influence of thin-film properties on the reliability of ultra-thin glass”, 60th Annual SVC Technical Conference, 2017.
  • S. Weller, M. Junghähnel: „Flash Lamp Annealing of ITO thin films on ultra-thin glass“, Vakuum in Forschung und Praxis 27 (4), S. 29-33, 2015.
  • M. Junghähnel, S. Weller, T. Gebel, „P-65: Advanced Processing of ITO and IZO Thin Films on Flexible Glass,” SID Symposium Digest of Technical Papers 46 (1), S. 1378–1381, 2015.
  • J. Westphalen: „Untersuchung der Eigenschaften von gesputterten ZnO:Al-Schichten auf flexiblem Glas, Masterarbeit, Technische Universität Ilmenau, Fakultät für Mathematik und Naturwissenschaften (2015).