The surface contaminants or residues on silicon wafers were investigated by a new combined technique of secondary ion mass spectrometry (SIMS) and electron stimulated desorption mass spectrometry (ESDMS) together with the field limiting method. The appearing peaks in the ESDMS spectra were due to the adsorbed species alone while those in the SIMS spectra were due to the substrate constituents as well as adsorbed species. Analysis by ESDMS was particularly useful for the detection and identification of the outermost layer species and for the evaluation of the surface cleanliness. The present combined technique can be a useful tool for analyzing complementarily the substrate by SIMS and the surface by ESDMS.