Salvador-Porroche Alba, Sangiao Soraya, Magén César, Barrado Mariano, Philipp Patrick, Belotcerkovtceva Daria, Kamalakar M Venkata, Cea Pilar, De Teresa José María
Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza 50009 Zaragoza Spain
Laboratorio de Microscopías Avanzadas (LMA), Universidad de Zaragoza 50018 Zaragoza Spain.
Nanoscale Adv. 2021 Aug 25;3(19):5656-5662. doi: 10.1039/d1na00580d. eCollection 2021 Sep 28.
Emergent technologies are required in the field of nanoelectronics for improved contacts and interconnects at nano and micro-scale. In this work, we report a highly-efficient nanolithography process for the growth of cobalt nanostructures requiring an ultra-low charge dose (15 μC cm, unprecedented in single-step charge-based nanopatterning). This resist-free process consists in the condensation of a ∼28 nm-thick Co(CO) layer on a substrate held at -100 °C, its irradiation with a Ga focused ion beam, and substrate heating up to room temperature. The resulting cobalt-based deposits exhibit sub-100 nm lateral resolution, display metallic behaviour (room-temperature resistivity of 200 μΩ cm), present ferromagnetic properties (magnetization at room temperature of 400 emu cm) and can be grown in large areas. To put these results in perspective, similar properties can be achieved by room-temperature focused ion beam induced deposition and the same precursor only if a 2 × 10 times higher charge dose is used. We demonstrate the application of such an ultra-fast growth process to directly create electrical contacts onto graphene ribbons, opening the route for a broad application of this technology to any 2D material. In addition, the application of these cryo-deposits for hard masking is demonstrated, confirming its structural functionality.
纳米电子学领域需要新兴技术来改善纳米和微米尺度的接触与互连。在这项工作中，我们报告了一种用于生长钴纳米结构的高效纳米光刻工艺，该工艺需要超低电荷剂量（15 μC/cm，在基于电荷的单步纳米图案化中是前所未有的）。这种无抗蚀剂工艺包括在保持在 -100°C 的衬底上冷凝一层约 28 nm 厚的 Co(CO) 层，用 Ga 聚焦离子束对其进行辐照，以及将衬底加热到室温。所得的钴基沉积物具有亚 100 nm 的横向分辨率，显示出金属行为（室温电阻率为 200 μΩ·cm），呈现铁磁特性（室温磁化强度为 400 emu/cm³），并且可以大面积生长。为了正确看待这些结果，只有在使用高 2×10 倍的电荷剂量时，通过室温聚焦离子束诱导沉积和相同的前驱体才能实现类似的性能。我们展示了这种超快速生长工艺在直接在石墨烯带上创建电接触方面的应用，为该技术在任何二维材料上的广泛应用开辟了道路。此外，还展示了这些低温沉积物用于硬掩膜的应用，证实了其结构功能。
