GENERATION AND HEALING OF LOW-ENERGY ION-INDUCED DEFECTS ON SI(100)-2X1

Tunneling microscopy of Si(100) surfaces following exposure to similar to 200 eV Xef irradiation at various temperatures reveals both the atomic geometry and the relative stabilities of surface defects created under low-energy sputtering. Both adatoms and vacancies are created by incident ions. Above 370 degrees C, mutual annihilation of adatoms and vacancies formed during sputtering enables layerwise removal of Si without adatom island formation. The metastability of decorated antiphase boundaries is responsible for the formation and persistence of long, narrow islands and of rough step edges on sputtered surfaces annealed as high as 700 degrees C.