The effect of redeposition on the ion flux dependence of Si dot pattern formation during ion sputter erosion

Abstract

We report an ion flux dependence study of the Si dot pattern formed on Si(100) by Ar+ ion sputtering with the ion energy being 1.5 keV, ion dose 5 × 1017 ions cm−2, and ion flux ranging from 280 to 1100 µA cm−2. Experimental results show that the lateral dot diameter d and the ion flux f basically follow the relationship of , and the surface roughness w decreases with increasing f in an exponential decay manner. Simulations based on a widely accepted continuum model, namely the noisy Kuramoto–Sivashinsky equation, reproduced the trend for d versus f but failed to explain that for w versus f. A redeposition consideration was then suggested. It is found that with this correction not only are the d–f and w–f relationships well explained, but the simulated surface morphology bears closer resemblance to the experimental one as well. The effect of redeposition becomes important for f> ∼130 µA cm−2 as derived in this work.

Is keV ion-induced pattern formation on Si(001) caused by metal impurities?

“…With ion energies of the order of 1 keV and for noble gases like Ar + , Kr + or Xe + and angles ϑ ≤ 30 • a large variety of dot and ripple patterns was obtained by us [14,27,28,29] and other groups [15,16,17,18,23]. We consider these results to be at variance with the present findings.…”

“…While there are certain conditions, where ion beam erosion of Si does not cause pattern formation [13,14], the overwhelming number of investigations find pattern formation on Si in a large parameter space. One class of prototypical patterns are dot or hole patterns observed for normal incidence noble gas ion erosion with energies up to a few keV and at temperatures in the amorphization regime [14][15][16][17][18][19]. Another class of exemplary patterns are ripple ones with the ripple wavevector k parallel to the ion beam azimuth.…”

Highly ordered nanopatterns on Ge and Si surfaces by ion beam sputtering

“…At end, it is mentioning that the above discussion would explain the different results obtained from different research groups (and the difficulty in reproducing these results) for nanostructures on Si and Ge surfaces [55][56][57][58][59].…”

In situx-ray studies of native and Mo-seeded surface nanostructuring during ion bombardment of Si(100)

“…their behavior in the absence of seeding [2]. For the particular case of Si substrates, the target examined in this work, studies of the native surface evolution at room temperature have reported that low-energy normal-incidence Ar + bombardment causes nanodot formation [3][4][5], or that it does not [6]. Experiments find that off-axis bombardment creates ripples [7,8], but some report that there is a window of incident angles over which the surface remains smooth [4].…”