Abstract The presence of inhomogeneous distribution of defects in GaAs wafers strongly limits the reproducibility of IC fabrication processes. In this paper, we report for the first time a Fourier transformation image testing approach, called FTIT, for the two dimensional evaluation of the disorder in a wafer, as it appears in infrared transmission timages. The Fourier analysis of the cell structure reveals a dominat statistical rectangular organization of the dislocations along <110> and <010> directions. The α and β defined in the paper are typical organization of the cells to evaluate quantitatively the properties of IC materials.