Low-energy Ion Scattering Measurement of Near-surface Damage Induced by the SiO2 Dry-Etching Process

Si(100) surface crystallinity after dry etching was measured using low-energy ion scattering spectroscopy (LEIS). We used 4-keV He⁺ ions as the incident beam, and neutral particles back-scattered at 180° were detected. A heavily damaged layer was observed immediately after reactive ion etching. After the heavily damaged layer was removed using a post-etch treatment, channeling and focusing effects were observed. The presence of a modified layer was confirmed even after the suboxide-rich layers were removed, because the channeling and focusing effects were slightly weaker than those of the surface without dry etching.