Ga Lithography in Sputtered Niobium for Superconductive Micro and Nanowires.
Ga Lithography in Sputtered Niobium for Superconductive Micro and Nanowires.
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用于超导微米线和纳米线的溅射铌 Ga 光刻。
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
R. Lewis
中科院分区：
文献类型：
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作者：
M. Henry;S. Wolfley;T. Monson;R. Lewis
这项工作演示了使用聚焦离子束（FIB）注入Ga作为等离子体刻蚀Nb膜的光刻掩模。使用FIB的高度准直的Ga束，Nb被注入12nm深，具有14nm厚的Ga层，利用基于氟的蚀刻化学提供优于15：1的蚀刻选择性。10 μ m × 10 μ m和100 μm × 100 μ m的注入方形测试图案表明，在30 kV下，剂量超过7.5 × 1015 cm−2，可为205 nm厚的溅射Nb膜提供足够的掩模保护。这种干法光刻技术的分辨率通过制造连接到50 μm宽的接触焊盘的75 nm宽× 10 μm长的纳米线来证明。图案化的Nb膜的剩余电阻比为3。利用磁性能测量系统测量了超导转变温度（Tc）= 7.7K。这种纳米级干法光刻技术在这里扩展到溅射TiN和Ta，并且可以用于其他氟蚀刻超导体，如NbN，NbSi和NbTi。
This work demonstrates the use of focused ion beam (FIB) implanted Ga as a lithographic mask for plasma etching of Nb films. Using a highly collimated Ga beam of a FIB, Nb is implanted 12 nm deep with a 14 nm thick Ga layer providing etch selectivity better than 15:1 with fluorine based etch chemistry. Implanted square test patterns, both 10 μm by 10 μm and 100 μm by 100 μm, demonstrate that doses above than 7.5 × 1015 cm−2 at 30 kV provide adequate mask protection for a 205 nm thick, sputtered Nb film. The resolution of this dry lithographic technique is demonstrated by fabrication of nanowires 75 nm wide by 10 μm long connected to 50 μm wide contact pads. The residual resistance ratio of patterned Nb films was 3. The superconducting transition temperature (Tc) = 7.7 K was measured using a magnetic properties measurement system. This nanoscale, dry lithographic technique was extended to sputtered TiN and Ta here and could be used on other fluorine etched superconductors such as NbN, NbSi, and NbTi.