Reactive magnetron sputtering for the large-area deposition of chalcopyrite absorber layers for thin-film solar cells

摘要

Reactive magnetron sputtering is interesting as a large-area process for the production of absorber layers in thin-film solar cells. However, since absorber layers must have a high electronic quality and thus a low defect content, so far no solar cells with satisfactory efficiencies could be produced with magnetron sputtering due to the high-energy particle and ion bombardment of the layer to be produced. With the invention, therefore, a special combination of different sputtering parameters is shown, whereby absorber layers can be deposited, which lead to efficiencies in solar cells, which correspond to those of solar cells produced by sulfurization. In this case, low-defect indium-rich sulfide-based chalcopyrite absorber layers can be produced without additional chemical etching steps, since no chalcopyrite molecules can be formed despite a comparatively low substrate temperature. In particular, in the case of high-frequency plasma excitation, the reactive gas content is adjusted to 5 to 30% of the inert gas content in the magnetron plasma, the chalcogen-containing reactive gas preferably being introduced horizontally directly on the substrate (3) (5) and deposited on the copper substrate with a negative bias setting on the substrate.