Phase evolution and morphology in Cu-In-Ga sputtered precursors

The reaction of metallic precursors has become the primary method of industrial manufacturing for Cu(In,Ga)Se-2. Commonly used Cu3Ga sputter targets have thus far dictated that the relative Ga composition of these precursors is Ga/(In+Ga) & AP; 0.25. Cu-In-Ga precursors are prepared with varying DC sputtering conditions and Ga compositions ranging from 0 & LE; Ga/(In+Ga) & LE; 0.75. The phase evolution and morphology of these precursors is characterized using x-ray diffraction (XRD) and scanning electron microscopy, including in situ annealing of precursors during XRD measurements. It is observed that the Ga composition of as-deposited precursors affects phase evolution with annealing. Consistent morphology changes were not observed with changing Ga, however, film morphology was controlled by adjusting In sputter conditions.