Abstract
In this thesis we developed sputtering process of CIGS absorber layers using a single quaternary-CIGS target. CIGS films were prepared without post-selenization by one-step RF sputtering at different substrate temperature. Additionally, a series of analysis on CIGS films was performed. Two kinds of quaternary-CIGS targets with different composition were used in this thesis. One is copper-rich and the other is copper-poor. (The composition ratio of the copper-rich is Cu: 22.7 %, In: 18.2 %, Ga: 8.1 %, Se: 51.0 % and the composition ratio of the copper-poor is Cu: 18.0 %, In: 18.2 %, Ga: 8.1 %, Se: 55.7 %.) To investigate properties of CIGS films, it was observed that second phases of copper selenide and indium selenide occurred during fabrication of CIGS films. The copper-selenide phase is conductive and a leakage-current path in CIGS films. Hence we altered the 22%-Cu target into the 18%-Cu target in order to suppress the formation of Cu-Se phases. Finally, the efficiency of 4.04% was achieved and the effective area up to 0.2 cm2. The CIGS solar cell fabricated by sputtering process without post-selenization is feasible.