Accurate quantification of Cu(In,Ga)Se2 films by AES depth profiling analysis

Quantitative analysis of Cu(In,Ga)Se2 (CIGS) films with non-uniform depth distributions was investigated by Auger electron spectroscopy (AES) depth profiling. The atomic fractions of the CIGS films were measured by relative sensitivity factors determined by a total number counting method from a CIGS reference film certified by isotope dilution–inductively coupled plasma/mass spectrometry. In the AES depth profiling analysis of the CIGS films, the intensities of Auger electron peaks in Cu, In, Ga and Se were determined by integrating the individual Auger peak intensities in the whole depth range of the AES depth profiles. The atomic fractions measured by AES analysis were linearly proportional to the certified values. The uncertainty in the AES depth profiling analysis of CIGS films was much smaller than that in the secondary ion mass spectrometry depth profiling analysis and that in the international comparison of national metrology institutes for the quantification of Fe–Ni alloy films.