A Close-Packed-Carbon-Nanotube Film on SiC for Thermal Interface Material Applications

Norimatsu, Wataru; Kawai, Chihiro; Kusunoki, Michiko

doi:10.5772/17269

Cited by 4 publications

(5 citation statements)

References 8 publications

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“…The highresolution TEM image shows the presence of (OOO2) graphite lattice fringes perpendicular to the SiC as shown in Figure 1(b). These fringes are the walls of the multiwalled carbon nanotubes and therefore show that CNTs can easily form onto the SiC substrate at the atomic scale [10]. As well as aligned CNT bundles being closely packed and well aligned have a diameter of approximately 30nm in Figure 1a.…”

Section: Carbon Nanotubesmentioning

confidence: 92%

“…A vertically aligned CNT film can be formed on SiC by a surface decomposition method to obtain properties such as high-density, well-aligned, catalyst-free, flexible CNT tips, high thermal conductivity and high adhesive strength, which are features that meet the requirements of a TIM [10]. The planar density of CNTs obtained by surface decomposition of SiC is approximated to be 3x10 4 µm -2 , which is hundred times as high as that of CNTs grown by the CVD method.…”

Section: Carbon Nanotubesmentioning

confidence: 99%

“…In order to demonstrate the difference thickness can make, a single SiC crystal was coated with silicon grease of thickness 50µm compared to a thickness of 1µm [10]. The thermal resistance measured were 0.79 K/W and 0.04 K/W, suggesting that smaller thickness is largely more effective.…”

Section: Cnt/sic Compositementioning

confidence: 99%

“…The thermal resistance measured were 0.79 K/W and 0.04 K/W, suggesting that smaller thickness is largely more effective. The materials with CNTs, without CNTs and single crystal SiC were then compared between CVD method (CVD-SiC), 1µm-CNT/CVD-SiC and 4µm-CNT/CVD-SiC and produced results of 0.43, 0.33, 0.26 K/W respectively [10]. This demonstrates that the resistance of CVD-SiC is higher than that of single crystal SiC because of thermal scattering due to the presence of grain boundaries, however the resistance can be reduced by forming CNTs onto SiC.…”

Section: Cnt/sic Compositementioning

confidence: 99%

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A Meta-study on the Thermal Properties of Carbon Nanotubes in Thermal Interface Materials

Clarkson¹,

Khan²,

Singh³

2019

PAMR

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Computer Integrated Circuit (IC) microprocessors are becoming more powerful and densely packed while cooling mechanisms are seeing an equivalent improvement to compensate. A significant limit to cooling performance is thermal transfer between die and heatsink. In this meta study we evaluate carbon nanotube (CNT) thermal interface materials (TIMs) in order to determine how to maximise thermal transfer efficiency. We gathered information from over 15 articles focused on the thermodynamic parameters of CNT TIMs from databases such as Scopus, IEEE Xplore and ScienceDirect. Articles were filtered by key words including ‘carbon nanotubes’ and ‘thermal interface materials’ to identify scientific articles relevant to our research on TIMs. From our meta study we have found that enhancing CNTs will provide the best improvement in TIMs. The parameters analysed to determine TIM performance included thermal resistance, thermal conductivity and the effect of CNT concentration on computer operation time. Through our investigation we understood that increasing the concentration of CNT from 0 to 2 wt % increases the operation time from 75 seconds at 66°C to 200s at 63°C as well as increasing the thermal conductivity by 1.82 times for the AS5 thermal paste with 2 wt % CNT. Furthermore, CNT TIM pastes with less thickness have a lower thermal resistance of 0.4 K/W. However not all these parameters have been tested with computer chips. This means that in order to increase current heat transfer efficiency limit, we must integrate these parameters into experimental models. Keywords: Thermal Interface Material; Thermal Paste; Carbon Nanotubes; Thermal Transfer Efficiency; Integrated Circuit; Heat Sink; Heat Dissipation.

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Section: Carbon Nanotubesmentioning

confidence: 92%

Section: Carbon Nanotubesmentioning

confidence: 99%

Section: Cnt/sic Compositementioning

confidence: 99%

Section: Cnt/sic Compositementioning

confidence: 99%

See 2 more Smart Citations

A Meta-study on the Thermal Properties of Carbon Nanotubes in Thermal Interface Materials

Clarkson¹,

Khan²,

Singh³

2019

PAMR

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“…In contrast, CNTs have excellent thermal conductivity. A CNT forest formed by SiC surface decomposition [1][2][3][4] is a densely packed forest and is ideal for application as not only a heat sink [1] but also an ohmic contact in SiC power transistors. [2] We have reported the contact resistivity of CNT/SiC interfaces comprising a CNT forest on SiC covered with a metal (Au/Ti).…”

Section: Introductionmentioning

confidence: 99%

Ohmic Contact for Silicon Carbide by Carbon Nanotubes

Inaba

Suzuki

Hirano

et al. 2016

MSF

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The electrical contact properties of silicon carbide (SiC) and carbon nanotubes (CNTs) were measured by conductive atomic force microscopy (C-AFM). A CNT forest was synthesized by SiC surface decomposition. Trenches, which electrically separate the conduction area, were fabricated using a focused ion beam (FIB) without a cover layer, and the resistance of each island was measured by C-AFM. From the dependence of the resistance on the CNT forest island size, the contact resistance between the CNTs and the SiC substrate was measured. By varying the dopant density in the SiC substrate, the Schottky barrier height was evaluated to be ~0.5 eV. This is slightly higher than a previously reported result obtained from a similar setup with a metal covering the CNT forest. We assumed that the damaged region existed in the islands, which is due to the trench formation by the FIB. The commensurate barrier height was obtained with the length of the damaged region assumed to be ~3 μm. Here, we could estimate the resistivity of a CNT/SiC interface without a cover layer. This indicates that a CNT forest on SiC is useful as a brief contact electrode.

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Vertical edge graphite layer on recovered diamond (001) after high‐dose ion implantation and high‐temperature annealing

Inaba

Seki

Sato

et al. 2017

Physica Status Solidi (b)

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A vertical edge graphite layer (VEG) fabricated on a diamond (001) substrate and the recovery of the crystallinity of the diamond substrate following high‐dose ion implantation and high‐temperature annealing (HTA) was investigated. The Al ions were implanted into the diamond (001) surface at 773 K (500 °C), followed by HTA at 1973 K (1700 °C). The graphite edges were vertically oriented, but each domain was randomly rotated in the in‐plane direction, which was confirmed via multiple cross‐sectional transmission electron microscopy images obtained from different directions rotated 2, 5, 10, and 15° around the [001] axis. The Raman and photoluminescence exhibited no significant peaks. The initial sp2 structure state of the VEG was nucleated in an early stage of the HTA and the surface diamond was subsequently reconstructed, which was confirmed using stopping‐and‐range‐of‐ions‐in‐matter calculations and Rutherford backscattering/channeling (RBS‐C) measurements. The RBS‐C spectra indicate that the crystal is maintained after hot implantation and is recovered by HTA. This VEG structure may be useful for ohmic contact with diamond electrical devices.

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A Close-Packed-Carbon-Nanotube Film on SiC for Thermal Interface Material Applications

Cited by 4 publications

References 8 publications

A Meta-study on the Thermal Properties of Carbon Nanotubes in Thermal Interface Materials

A Meta-study on the Thermal Properties of Carbon Nanotubes in Thermal Interface Materials

Ohmic Contact for Silicon Carbide by Carbon Nanotubes

Vertical edge graphite layer on recovered diamond (001) after high‐dose ion implantation and high‐temperature annealing

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