The authors explore the combination of high power impulse magnetron sputtering (HiPIMS) and substrate bias for the epitaxial growth of the Cu film on the Cu (111) substrate by molecular dynamics simulation. A fully ionized deposition flux was used to represent the high ionization fraction in the HiPIMS process. To mimic different substrate bias, the authors assumed the deposition flux with a flat energy distribution in the low, moderate, and high energy ranges. The authors also compared the results of the fully ionized flux with results assuming a completely neutral flux, in analogy with thermal evaporation. It is confirmed that in the low energy regime, HiPIMS presents a slightly smoother surface and more interface mixing compared to that of thermal evaporation. In the moderate energy HiPIMS, however, an atomically smooth surface was obtained with a slight increase in the interface mixing compared to low energy HiPIMS. In the high energy regime, HiPIMS presents severe interface mixing with a smooth surface but limited growth due to resputtering from the surface. The results also indicate that fewer crystal defects appear in the film for moderate energy HiPIMS. The authors attribute this behavior to the repetition frequency of collision events. In particular, the high energy HiPIMS suffers from high repetition of collision events that does not allow the reconstruction of the film. While in the low energy HiPIMS, there are not enough events to overcome the island growth. At moderate energy, collision events repeat in a manner that provides enough time for reconstruction, which results in a smooth surface, fewer defects, and limited intermixing.

中文翻译：

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衬底偏压对HiPIMS生长的外延膜微观结构的影响：原子模拟

作者探索了大功率脉冲磁控溅射（HiPIMS）和衬底偏压的结合，通过分子动力学模拟在Cu（111）衬底上外延生长Cu膜。在HiPIMS工艺中，完全电离的沉积通量用于表示高电离分数。为了模拟不同的衬底偏压，作者假设沉积通量在低，中和高能量范围内具有平坦的能量分布。作者还将完全电离的通量的结果与假定为完全中性的通量的结果进行了比较，类似于热蒸发。可以肯定的是，在低能量条件下，与热蒸发相比，HiPIMS的表面稍微更光滑，界面混合更多。但是，在中等能量的HiPIMS中，与低能HiPIMS相比，获得的原子光滑表面的界面混合略有增加。在高能状态下，HiPIMS呈现出严重的界面混合，表面光滑，但由于从表面重新溅射而导致生长受限。结果还表明，对于中等能量的HiPIMS，薄膜中出现的晶体缺陷更少。作者将此行为归因于碰撞事件的重复频率。特别地，高能量HiPIMS遭受碰撞事件的高度重复，这不允许电影的重建。在低能耗HiPIMS中，没有足够的事件来克服岛屿的增长。在适度的能量下，碰撞事件以提供足够的重建时间的方式重复出现，从而导致表面光滑，缺陷少并且混合受限。