中国科学院上海微系统所《ACS ANM》：直径调控垂直石墨烯包覆铜线，增强热稳定性与载流能力

铜凭借其优异的导电、导热性与低成本，在电力、通信及电子领域不可或缺。然而，器件持续微型化使铜线的载流能力（ampacity）与环境稳定性面临严峻挑战——尤其在高温、氧化等严苛工况下，铜线的性能衰减成为微细导线可靠性的瓶颈。因此，开发兼具导电保持与防护功能的铜线改性策略具有重要意义。基于此，本文，中科院上海微系统与信息技术研究所时志远、于庆凯团队在《ACS Applied Nano Materials》期刊发表题名”Diameter-Governed Vertical Growth of Graphene-Skinned Cu Wires with Enhanced Thermal Stability”的研究，采用固态碳源、无需额外加热的工艺，在 18 μm、500μm与1mm三种直径的铜线表面制备出垂直取向的石墨烯包覆层。

此外，研究发现不同直径铜线上石墨烯形貌的差异源于其热响应不同，以及裸露催化面积对生长的影响——细直径铜线升温更快、催化面积受限，更易诱导垂直取向生长；论文进一步以 18 μm 铜线为例，揭示了垂直石墨烯的生长过程与结构特征。经对比表征，垂直石墨烯相较水平石墨烯展现出更优的抗氧化性；在保持铜线本征电学性能的同时，垂直石墨烯包覆层显著提升了铜线的热稳定性与载流能力。本研究提出了一种将导电性、散热性与耐久性集于一体的铜线包覆策略，为严苛环境下微细导线的防护提供了低能耗、可规模化的涂层思路。

Figure 1.Graphene (Gr) growth on 18 μm, 500 μm, and 1 mm Cu wires. (a) Schematic illustration of VG growth. (b−d) OM images of the pristine Cu wires. (e−g) SEM images of graphene on the Cu wires. (h−j) Raman spectra of graphene on the Cu wires.

Figure 2.(a) 3D structural diagram of the COMSOL simulation of Cu wire temperature. (b) Summary of simulation temperature results for Cu wires of different sizes at plasma powers of 50 W and 100 W. (c−e) SEM images of VG grown on the 18 μm, 500 μm, and 1 mm Cu wires under a plasma power of 100 W. (f−h) Raman spectra of VG grown on the 18 μm, 500 μm, and 1 mm Cu wires under a plasma power of 100 W.

Figure 3.Investigation of the VG growth process on 18 μm Cu wires. (a) Schematic diagram of the different stages of VG growth on Cu wires. (b) OM images of the pristine Cu wire, the Cu wire after 30 min of growth, and the Cu wire after 60 min of growth. (c) Raman spectra of graphene with different growth times. (d−h) SEM images of the pristine Cu wire and the Cu wires after 10 min, 20 min, 30 min, and 60 min of growth.

Figure 4.Characterization of VG grown on the 18 μm Cu wire. (a) SEM image of VG on the surface of the 18 μm Cu wire. (b) AFM image of VG on the surface of the 18 μm Cu wire. (c) TEM image of VG transferred onto a TEM grid. (d) SAED pattern of VG. (e) HR-TEM image of VG.

Figure 5.Oxidation resistance testing of bare Cu wire, Gr-Cu, and VG-Cu. (a) OM images of the three Cu wire samples before and after oxidation at 200 °C in air for 5 min. (b) Raman spectra of the three Cu wire samples before oxidation. (c) Raman spectra of the three Cu wire samples after oxidation.

Figure 6.The electrical performance test of 18 μm Cu wires. (a) The conductivity of A-Cu, Gr-Cu and VG-Cu. (b) TCR values of A-Cu, Gr-Cu and VG-Cu. (c) I−V curves of A-Cu, Gr-Cu and VG-Cu. (d) The maximum current density extracted from the I−V curves.

本研究采用固态碳源、无需额外加热的工艺，在 18 μm、500 μm 与 1 mm 三种直径的铜线表面构建了垂直石墨烯包覆层。基于不同直径铜线热响应与裸露催化面积的差异，实现了石墨烯取向的直径调控生长。研究结果表明，垂直石墨烯相较水平石墨烯具有更优的抗氧化性，并在保持铜线电学性能的同时，提升了其热稳定性与载流能力。同时，该工艺无需额外加热，能耗低、易于规模化。本YANJIU 为严苛环境下微细导线的防护提供了一种集导电、散热与耐久于一体的低能耗包覆策略，有望在微电子互连、功率传输与高可靠线束等领域拓展应用。

文献：https://doi.org/10.1021/acsanm.6c03696