A comparative study of the dry and wet nano-scale electro-machining
A comparative study of the dry and wet nano-scale electro-machining
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DOI：
10.1016/j.procir.2013.03.081
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
M. Jahan;K. Virwani;K. Rajurkar;A. Malshe
中科院分区：
文献类型：
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作者：
M. Jahan;K. Virwani;K. Rajurkar;A. Malshe
近年来，基于扫描隧道显微镜（STM）平台的纳米电加工（nano-EM）工艺得到了验证。纳米电磁能够在液体介质（湿纳米电磁）和空气介质（干纳米电磁）下加工纳米特征。本文的目的是在湿法和干法纳米电磁加工的工艺机理、加工性能、一致性和尺寸可重复性等方面对两种工艺进行比较研究。在近场纳米em下对两种工艺进行了比较，其中工具电极与工件之间的间隙为2 nm，加工在室温和压力下进行（宏观）。工艺机理的主要差异是由于介质界面处的介质、两种介质的击穿场强度和击穿特性以及材料去除机制的不同。研究表明，湿型纳米电磁的材料去除机制与纳米受限液体介质中场发射辅助雪崩有关，而干型纳米电磁的材料去除机制与场诱导材料蒸发有关。在加工性能、加工特征的尺寸和纳米级加工特征的可重复性方面也观察到差异。随着加工的继续，自尖端锐化过程在纳米尺度特征的尺寸、可重复性和加工性能方面增加了干式纳米电磁比湿式纳米电磁的几个优点。
In recent years, a nano-electromachining (nano-EM) process based on a scanning tunneling microscope (STM) platform has been demonstrated. Nano-EM is capable of machining nano-features, under both, liquid dielectric (wet nano-EM) and air dielectric (dry nano-EM) media. The objective of this paper is to present a comparative study between the wet and dry nano-EM processes based on process mechanism, machining performance, consistency and dimensional repeatability of these two processes. The comparison of the two processes has been conducted at near field nano-EM, where the gap between the tool electrode and workpiece is 2 nm and the machining is performed at room temperature and pressure (macroscopically). The major differences in the process mechanism are due to the media at dielectric interface, the breakdown field strength and breakdown characteristics of two dielectrics and therefore, the material removal mechanism. It is reported that the material removal mechanism of wet nano-EM is associated with field emission-assisted avalanche in nano-confined liquid dielectric, whereas, the material removal mechanism in dry nano-EM is associated with field-induced evaporation of material. The differences have also been observed in the machining performance, dimensions of the machined features and repeatability of the nanoscale machined features. The self-tip -sharpening process with the continuation of machining has added several advantages to dry nano-EM over wet nano-EM in terms of dimensions of the nanoscale features, repeatability and machining performance.