高电荷态氙离子辐照下的6H碳化硅表面纳米结构变形（英文）

6H-SiC surface nanostructure deformation under highly-charged Xe^(q+) irradiation

高电荷态离子比普通的离子携带较高的势能,势能在材料表面的瞬间释放,能在材料表面形成nm量级的结构损伤。它在纳米刻蚀、小型纳米器件、纳米材料、超小尺寸半导体芯片制作、固体表面处理和固体结构分析等领域具有广泛应用前景。因此对高电荷态重离子(Xeq+)引起半导体材料表面(6H-SiC)纳米结构变形进行了研究。采用Xe18+和Xe26+离子,选取从1×1014到5×1015 ions·cm-2逐渐递增的剂量,以垂直和倾斜60°角两种入射方式辐照6H-SiC薄膜样品,经原子力显微镜分析表明,辐照后的表面肿胀凸起。对于Xe18+离子辐照的样品,辐照区至未辐照区边界的台阶高度随离子剂量增加而连续增大,而对于Xe26+离子辐照的样品则先增加而后减小。在相同入射角和剂量条件下,Xe26+离子辐照样品形成的台阶高度大于Xe18+离子辐照形成的台阶高度,在相同离子和剂量的条件下,垂直照射时形成的台阶高度大于倾斜照射时形成的台阶高度。根据损伤机理和实验数据,首次初步建立了一个包括势能、电荷态、入射角和剂量等物理量的理论模型来预测高电荷态离子在半导体材料表面形成的纳米结构变形。暗示了高电荷态离子的潜在的应用价值及进一步研究的必要性。

Nanostructure deformation on 6H-SiC surface irradiated with highly-charged Xe^q＋（q=18,26）ions to different fluences in two geometries of incidence by means of atomic force microscopy has been studied.The AFM measurement reveals that the irradiated surface is swelling.With increasing ion fluences,the step height between the irradiated and the unirradiated regions increases for Xe^18＋irradiation.While for Xe^26＋the step height firstly increases,and then decreases with increasing ion fluences.Moreover,the step height at normal incidence is higher than that at a tilted incident angle for the same ion and dose.These results can be attributed to the competition between the damage accumulation and the potential sputtering.A preliminary model including potential energy,incident angle,charge state and dose that accounts for the formation of observed nanostructures is proposed to discuss the underlying mechanism and to predict the step height.The paper concludes with suggestions for further research on the work and its potential applications.