The incorporation of metal impurities M (M = Ti, Fe, or Sn) into CuGaS(2) films is investigated experimentally as a function of impurity concentration. Films are synthesized by thermal co-evaporation of the elements onto glass/Mo substrates heated to 400 degrees C-570 degrees C. The compositions of the resulting films are measured by energy-dispersive X-ray spectroscopy and the structures of the present phases are studied by X-ray diffraction. The formation of Cu-M-S ternary phases is observed in a wide range of conditions. Films of Cu-Ga-Ti-S, synthesized at 500 degrees C, show the presence of a cubic modification of CuGaS(2) and Cu(4)TiS(4). Alloying of CuGaS(2) and tetragonal Cu(2)SnS(3) is observed for substrate temperatures of 450 degrees C. A miscibility gap opens at 500 degrees C and above with separate Sn-rich and Ga-rich phases. Similarly, alloys of CuFeS(2) and CuGaS(2) are only found in Cu-Ga-Fe-S films synthesized at lower substrate temperature (400 degrees C), whereas at 500 degrees C a miscibility gap opens leading to separate Fe-rich and Ga-rich phases. (C) 2011 Elsevier B.V. All rights reserved.