Due to the increasing global energy demand, the threat of climate change and the associated need to reduce CO2 emissions and the increasing uncertainty in the energy supply, the use of renewable energies is of increasing interest. Especially the generation of electrical energy from fossil fuels, should be minimized or even substituted by photovoltaic systems. To produce solar cells, there are several ways where the silicon technology was state of the art, for a long period. Due to the detailed know how for the production of so-called silicon wafers, the process is still very widespread, used, however in recent years, increasing substitution by other materials and manufacturing methods taking place. Although silicon is practically infinite available in the form of sand on Earth, but the extraction of the pure metal is very energy consuming and thus costly. The best alternative to silicon and also its biggest competitor at the same place are the so-called chalcopyrite semiconductors. As the main representative of this species is the Cu(In,Ga)Se2 semiconductor. With the help of a one- or two-stage process a layer sequence consisting of the metals Cu, Ga, In and Se, the so-called precursor, is produced. An annealing process at a temperature of about 550 °C, transforms the elements to the semiconductor Cu (In1-xGax) Se2. The central element of the solar cell, the strongly absorbing, photo-electrically active layer is formed during the thermal process. Therefore this sub-process is very important at the production of a thin-film-cell of particular importance. The aim of the present study was to test an existing facility that was used for thermal treatment of metal strips of different composition, to be adapted for a selenization-process. It has to be taken especially on the toxicity of selenium hydrogen. In contrast to usual practice, the goal was not to deposit the precursor on a glass plate but on a thin steel strip which is then thermally treated in one step, and to investigate this compound with microscopic and with X-ray diffraction.