Electron-Stimulated Modification of Si Surfaces

Abstract

Scanning tunneling microscopy studies show significant structural modifications that involved atom desorption and displacement following mild irradiation by electrons of 90–2000 eV. For $\mathrm{Si}\left(111\right)-(7\times 7)$, adatom layer vacancies increased monotonically with incident energy. For $\mathrm{Si}\left(100\right)-(2\times 1)$, irradiation produced dimer vacancies, and ad-dimers as Si atoms transferred to the terrace. The modification processes are tied to the energy distribution of electron-hole and electron attachment states achieved by inelastic cascade scattering. Hence, beams previously believed to be benign induce surface structural modifications.