Investigation of sputtered Mo layers on soda-lime glass substrates for CIGS solar cells

The influences of deposition parameters on the structural, electrical and mechanical properties of the molybdenum films deposited on the soda-lime glass substrates by dc magnetron sputtering were investigated. The results revealed that there was a significant impact of working pressure on the properties of as-deposited Mo films. The surface morphology of films varied from dense to porous microstructure as working pressure was increased. Under low working pressure, the films possessed low resistivity but poor adhesion. In contrast, the films deposited at high working pressure exhibited good adhesion but high resistivity. Moreover, the high sputtering power and the low sputtering voltage reduced the resistivity and enhanced the adhesion of Mo films, respectively. In order to improve the resistivity and adhesion of Mo films, a bi-layer structure deposited under different conditions was studied. Under the given deposition conditions, both low resistivity of 9.71 µΩ cm and good adhesion have been achieved for the Mo films with a bi-layer structure.