Cu(InGa)Se2 thin films by elemental co-evaporation/sputtering and large area module results

We report process optimization and understanding resulting in high quality Cu(In,Ga)Se₂ (CIGS) films and high efficiency devices/modules using a hybrid process for CIGS formation. In the hybrid process, the Cu is supplied by magnetron sputtering, and the In, Ga, and Se are supplied by linear thermal sources. The advantages of the hybrid process include: i) the ease and precision of Cu thickness control; and ii) flexibility to adjust the Ga depth profile. The investigation was conducted in a large-area, pilot-line system. Among others, important parameters were found to be the Cu/(In+Ga) ratio of the Cu/(InGa)₂Se₃ precursor, selenization temperature, and timing of the Ga and In fluxes. Cell efficiencies of over 13.0% and module efficiencies of 7.5% (26 W, 0.35 m²) were achieved. The film properties were investigated by XRD, SEM, and AES.