An investigation on preparation of CIGS targets by sintering process

Pressureless sintering process was used to fabricate CIGS targets with Cu2Se, In2Se3, and Ga2Se3 as raw powders mixed according to the stoichiometry of CuIn0.72Ga0.28Se2 (CIGS). The results showed that only CuIn0.7Ga0.3Se2 phase can be detected in the sintered targets. The pores in sintered specimen become smaller and distribute more homogeneously under the conditions of finer powders and higher cold pressure. Both mass loss caused by the formation of volatile phase relating to Ga and volume expansion occur during the sintering process, which result in the decrease of density. The tendency of anti-densification becomes stronger under the conditions of coarser powders and higher cold pressure. The sintering process and causes for anti-densification were discussed. Finally, a hot pressing process was carried out, which was proved to be fairly effective to increase the density of CIGS target. The fabricated target can be used for magnetron-sputtering deposition of CIGS absorbers.