Nanostructuring of Si(100) by normal-incident Ar+ ion sputtering at low ion flux

We investigate Si(100) surface morphology evolution under normal-incident Ar+ ions sputtering with low ion flux of 20muA/cm(2). The results indicate that under the low flux ion sputtering, the nanostructuring process of Si(100) is governed by the Ehrlich-Schwoebel (ES) mechanism, rather than by the Bradley-Harper (BH) one for the case of high flux (normally the order of 10(2) muA/cm(2) or larger). This work reveals that the ion flux plays an important role in the surface morphology evolution under ion sputtering, and a usually accepted classification that the ES mechanism is related to metal single-crystals under ion sputtering, while the BH one is to amorphous, and semiconductor targets is questionable.