Ion-Sputter-Induced Nanodots on Si（110）： Ion Energy Dependence

Nanodot arrays were formed on Si(110) surface under normal-incident Ar ion sputtering at substrate temperature of 800℃ The ion flux was 20μA/cm^2, and the ion energies were 1-5keV. The surface was imaged by an atomic force microscope (AFM). It was found that with the increasing ion energy, the average e11ipticity of the dots changes in an oscillating manner; meanwhile the average dot size increases monotonously. Based on a dynamic continuum model, and taking into consideration the asymmetry of the Ehrlich-Schwoebel diffusions along the(100) and (110) crystallographic directions, we carry out the simulations, which reproduce the experimental results qualitatively.     

离子束溅射致Si(110)表面形貌随样品温度变化的演化

本文研究了离子能量为1.5keV、束流密度为20?A/cm2正入射Ar+离子束溅射致Si(110)表面形貌随样品温度变化的演化过程。在温度自室温上升至 800?C的过程中, Si(110) 的表面形貌由不规则的纳米点和纳米孔图案变为密集的量子点阵列，同时表面粗糙度也随温度上升不断增加。被通常采用的 Bradley-Harper 模型无法解释上述实验数据。 在考虑溅射过程中存在Ehrlich-Schwoebel 效应后, 进行了已连续动态模型为基础的理论模拟，模拟工作很好的重复了实验结果。     

Nanostructuring of Si（lO0） 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 20μA/cm^2. The results indicate that under the low flux ion sputtering, the nanostructuring process of Si(lO0) is governed by the Ehrlich-Schwoebel (ES) mechanism, rather than by the Bradley-Harper (1311) one for the case of high flux (normally the order of 10^2 μA/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.