Comparison of Spectrum Cluster Analysis with PCA and Spherical SOM and Related Issues Not Amenable to PCA

A chemical spectral data set was analyzed with the PCA method and the SSOM method. The results are in agreement albeit that the PCA method is only valid when the number of spectral dimensionalities is small. This is not the case with the SSOM method. In the present paper, the data of the AES depth profile, where Sn was plated on Cu, and which has a high dimensionality, is also analyzed. These results show the excellence of the SSOM method.