The compositional distribution of Ga and S in Cu(InGa)(SeS)(2) films fabricated by a simultaneous selenization and sulfization process was systematically investigated. At low H2Se/H2S reaction temperature (490 degrees C), most Ga remains at the back of the film adjacent to the Mo back contact. However, the Ga/III ratios at the top and bottom of the Cu(InGa)(SeS)(2) layer monotonically increase and decrease with reaction temperatures, respectively. At T > 550 degrees C, homogeneous distribution of elemental Ga and In through film is achieved. Further increase of the reaction temperature (e.g., T > 550 degrees C) causes phase segregation on the surface of the Cu(InGa)(SeS)(2) film confirmed by XRD, GIXRD and EDS analysis. (C) 2010 Elsevier B.V. All rights reserved.