CdS large area thin films deposited on soda lime glass and conducting substrates by sputtering technique

The processing of large area thin films solar cells represents a challenge, mainly due to the optimal setting of the different critical growth parameters in this scaling-up process, than can guarantee a homogeneous-surface-photovoltaics response in the subminimodule architecture. We have been working with a radio-frequency planar magnetron sputtering (RF-PMS) system, processing 450 cm² areas of CdS thin films grown on soda lime glasses and conducting glasses (SnO₂:F-7Ω/□), using for it a 6" balanced gun. The films have been processed with different growth conditions, like substrate temperatures (100<T_s<275°C), Ar chamber-pressure (10<P_Ar <20 mTorr), and radio frequency power (rf-pw <310 watts). The films were characterized by several morphological, optical, structural and electrical techniques, presenting in this work the corresponding measurements. Our results show that the best polycrystalline perfection, adherence and pinholes free surfaces are obtained for growth conditions of T_s at 250°C