In this work, we report on the performances of superstrate Cu(In,Ga)Se(2) (CIGS) thin film solar cells with an alternative SLG/SnO(2):F/CIGS/In(2)Se(3)/Zn structure using AMPS-1D (Analysis of Microelectronic and Photonic structures) device simulator. An inverted surface layer, n-type CIGS layer, is inserted between the In(2)Se(3) buffer and CIGS absorber layers and the SnO(2):F layer is just a transparent conducting oxide (TCO). The simulation has been carried out by lighting through SnO(2):F. The obtained results show that the existence of so-called 'ordered defect compound' (ODC) layer in such a structure is the critical factor responsible for the optimization of the performances. Photovoltaic parameters were determined using the current density-voltage (J-V) curve. An optimal absorber and ODC layer thickness has been estimated, that improve significantly the devices efficiency exceeding 15% AM1.5 G. The variation of carrier density in In(2)Se(3) layer has an influence on the superstrate CIGS cells performances. Moreover, the quantum efficiency (Q.E.) characteristics display a maximum value of about 80% in the visible range. (C) 2011 Elsevier B.V. All rights reserved.