| 1. |
- Jiang, Di, 1983, et al.
(author)
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A flexible and stackable 3D interconnect system using growth-engineered carbon nanotube scaffolds
- 2017
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In: Flexible and Printed Electronics. - : IOP Publishing. - 2058-8585. ; 2:2
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Journal article (peer-reviewed)abstract
- One of the critical challenges for realizing flexible electronic systems for a wide range of applications is the development of materials for flexible and stackable interconnects. We propose and demonstrate a three-dimensional (3D)interconnect structure embedded in a polymeric substrate using metal-coated carbon nanotube (CNT)scaffolds. By using two different underlayer materials for the catalyst, onestep synthesis of a dual-height CNT interconnect scaffold was realized. The CNT scaffolds serve as flexible cores for both annular metal through-substrate-vias and for horizontal metal interconnect. The 3D-CNT network was fabricated on a silicon substrate, and once the scaffolds were covered by metal, they were embedded in a polymer serving as a flexible substrate after peel-off from the silicon substrate. The 3D-CNT interconnect network was exposed to mechanical bending and stretching tests while monitoring its electrical properties. Even after 300 cycles no significant increase of resistances was found. Electrically there is a trade-off between flexibility and conductivity due to the surface roughness of the scaffold. However, this is to some extent alleviated by the metalized sidewalls giving the horizontal wires a cross-sectional area larger than indicated by their footprint. For gold wires 200 nm thick, measurements indicated a resistivity of 18 μΩ.cm, a value less than one order of magnitude larger than that of bulk gold, and a value that is expected to improve as technology improves. The mechanical properties of the metalized scaffolds were simulated using a finite element model. The potential scale-up capability of the proposed 3D-CNT network was demonstrated by the stacking of two such polymer-embedded interconnect systems.
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| 2. |
- Zhang, Yong, 1982, et al.
(author)
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Chemical vapor deposition grown graphene on Cu-Pt alloys
- 2017
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In: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 193, s. 255-258
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Journal article (peer-reviewed)abstract
- In this letter, the results from a series of experiments where graphene was grown on copper-platinum (Cu-Pt) alloy foils by chemical vapor deposition (CVD) are presented. By using Raman spectroscopy to analyze graphene films grown on Pt-Cu alloy foils with different Cu/Pt weight ratios (75/25, 50/50 and 25/75), we could show how the Cu/Pt weight ratio affected both the quality and the number of layers in the as-synthesized graphene films. Furthermore, graphene growth was shown to occur at temperatures as low as 750 °C due to what we believe is the strong catalytic ability of the Cu-Pt alloy foils. By keeping the flow rate of the CH4 precursor gas as low as 1.5 sccm, a low growth rate was obtained where the growth rates of monolayer and bilayer graphene could be controlled by simply adjusting the growth time.
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