Atomic-scale thermocapillary flow in focused ion beam milling
Atomic-scale thermocapillary flow in focused ion beam milling
复制标题
聚焦离子束铣削中的原子级热毛细管流动
DOI：
10.1063/1.4919782
复制
发表时间：
2015
影响因子：
4.6
通讯作者：
J. Freund
中科院分区：
文献类型：
--
作者：
Kallol Das;H. Johnson;J. Freund
聚焦离子束提供了一种纳米级制造和材料加工的方法，用于在薄膜上形成纳米级孔以进行DNA测序等应用。我们用分子动力学模拟研究了镓离子轰击硅薄膜靶的这种构型。在实际配置中，对于离子强度的范围，形成了一个再循环的熔体区域，可以看到它以对称的模式流动，这与它在离子动量通量驱动下的流动方式相反。这种流动对形成的结构的形状和组成具有潜在的重要意义。在这些极端条件下，硅的相关应力尺度和估计的物理性质支持热毛细效应的重要性。基于原子模拟的温度梯度和几何形状，具有马兰戈尼强迫的流动模型确实再现了这种流动，因此可以用来预测这种流动及其在应用中的影响。
Focused ion beams provide a means of nanometer-scale manufacturing and material processing, which is used for applications such as forming nanometer-scale pores in thin films for DNA sequencing. We investigate such a configuration with Ga+ bombardment of a Si thin-film target using molecular dynamics simulation. For a range of ion intensities in a realistic configuration, a recirculating melt region develops, which is seen to flow with a symmetrical pattern, counter to how it would flow were it driven by the ion momentum flux. Such flow is potentially important for the shape and composition of the formed structures. Relevant stress scales and estimated physical properties of silicon under these extreme conditions support the importance thermocapillary effects. A flow model with Marangoni forcing, based upon the temperature gradient and geometry from the atomistic simulation, indeed reproduces the flow and thus could be used to anticipate such flows and their influence in applications.