A scanning electron-stimulated desorption (ESD) ion microscope (SESDIM) measured the 2-D images of hydrogen and oxygen distribution on solid surfaces. A primary electron beam at 600 eV, with a pulse width of 220 ns, resulted in ion yields of H+ and O+. This SESDIM is applied to the surface analysis of Porous-Si (Po-Si) partially covered with SiN films. During the heating of a specimen of the Po-Si at 800 degreesC under ultra-high-vacuum (UHV) conditions, the components of the surface materials were moved or diffused by thermal decomposition accompanied by a redistribution of hydrogen and oxygen. After cyclic heating of above 800 degreesC, the dynamic behaviors of H+ and O+ accompanied by the movements of the SiN layers were observed as images of H+ and O+. This was because the H+ and O+ ions have been identified as composite materials by their kinetic energies. (C) 2004 Elsevier B.V. All rights reserved.