Preferential sputtering of Si3N4

Auger peaks of 82-eV Si and 381-eV N have been used to study the preferential enrichment of one component of Si3N4 after sequential sputtering with 0.5- and 2.0-keV Ar+ and He+ ions. The results clearly indicate that the element enriched at the surface, due to sputtering, depends on the mass of the impinging ion, and the magnitude of the enrichment depends on the energy of the ion. For example, N was enriched by Ar+, while Si was enriched by He+ bombardment. These results are explained by considering direct knockoff and energy transfer processes in sputtering.