| 1. |
- Zhang, Dongsheng, et al.
(författare)
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Thermal properties of TIM using CNTs forest in electronics packaging
- 2016
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Ingår i: 2016 17th International Conference on Electronic Packaging Technology, ICEPT 2016; Wuhan Optics Valley Kingdom Hotel Wuhan; China; 16 August 2016 through 19 August 2016. ; , s. 1355-1359
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Konferensbidrag (refereegranskat)abstract
- Thermal interface material (TIM) is applied to fill the air gaps of interfaces, which provides a path for interfacial heat transfer. Owing to the exceptional thermal properties of carbon nanotubes (CNT), TIMs based on CNTs have received much attention in recent years. In this study, heat dissipation performance of vertically aligned carbon nanotubes (VACNT) arrays as TIM in electronic packing was analyzed. Vertically aligned carbon nanotubes with length of 245?m and 763?m were synthesized on a silicon substrate by chemical vapor deposition respectively. Morphology of the vertically aligned carbon nanotubes was characterized by scanning electron microscope. The hotspot temperature of thermal test chip with vertically aligned carbon nanotubes were characterized by resistance temperature detector method and infrared imaging method.
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| 2. |
- Bao, Jie, et al.
(författare)
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Application of two-dimensional layered hexagonal boron nitride in chip cooling
- 2016
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Ingår i: Yingyong Jichu yu Gongcheng Kexue Xuebao/Journal of Basic Science and Engineering. - 1005-0930. ; 24:1, s. 210-217
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Tidskriftsartikel (refereegranskat)abstract
- © 2016, The Editorial Board of Journal of Basic Science and Engineering. All right reserved.Research into layered hexagonal boron nitride(h-BN)has recently intensified, due to its superior physicochemical properties compared to that of a typical two-dimensional material. H-BN can be utilized in power chips as both an insulating layer as well as a heat spreader for local hotspots with high heat flux. Single layer h-BN film grown by CVD and h-BN microparticles are respectively transferred onto the surfaces of the thermal evaluation chips, where the influence of h-BN on the heat dissipation performance of the chips can be observed at different power values. The resistance-temperature curve method and infrared thermal imager are both used to measure the temperature of hotspots on the thermal evaluation chips, which can be reduced by between 3~5℃ at 1W after the transfer of h-BN. The cooling efficiency is improved and it can be found that single layer h-BN film shows better heat dissipation ability.
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| 3. |
- Bao, Jie, et al.
(författare)
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Synthesis and Applications of Two-Dimensional Hexagonal Boron Nitride in Electronics Manufacturing
- 2016
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Ingår i: Electronic Materials Letters. - : Springer Science and Business Media LLC. - 1738-8090 .- 2093-6788. ; 12:1, s. 1-16
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Forskningsöversikt (refereegranskat)abstract
- In similarity to graphene, two-dimensional (2D) hexagonal boron nitride (hBN) has some remarkable properties, such as mechanical robustness and high thermal conductivity. In addition, hBN has superb chemical stability and it is electrically insulating. 2D hBN has been considered a promising material for many applications in electronics, including 2D hBN based substrates, gate dielectrics for graphene transistors and interconnects, and electronic packaging insulators. This paper reviews the synthesis, transfer and fabrication of 2D hBN films, hBN based composites and hBN-based van der Waals heterostructures. In particular, this review focuses on applications in manufacturing electronic devices where the insulating and thermal properties of hBN can potentially be exploited. 2D hBN and related composite systems are emerging as new and industrially important materials, which could address many challenges in future complex electronics devices and systems.
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| 4. |
- Bao, Jie, 1982, et al.
(författare)
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Two-dimensional hexagonal boron nitride as lateral heat spreader in electrically insulating packaging
- 2016
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Ingår i: Journal of Physics D: Applied Physics. - : IOP Publishing. - 1361-6463 .- 0022-3727. ; 49:July 2016, s. 265501-
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Tidskriftsartikel (refereegranskat)abstract
- The need for electrically insulating materials with a high in-plane thermal conductivity for lateral heat spreading applications in electronic devices has intensified studies of layered hexagonal boron nitride (h-BN) films. Due to its physicochemical properties, h-BN can be utilised in power dissipating devices such as an electrically insulating heat spreader material for laterally redistributing the heat from hotspots caused by locally excessive heat flux densities. In this study, two types of boron nitride based heat spreader test structures have been assembled and evaluated for heat dissipation. The test structures separately utilised a few-layer h-BN film with and without graphene enhancement drop coated onto the hotspot test structure. The influence of the h-BN heat spreader films on the temperature distribution across the surface of the hotspot test structure was studied at a range of heat flux densities through the hotspot. It was found that the graphene-enhanced h-BN film reduced the hotspot temperature by about 8–10°C at a 1000 W/cm2 heat flux density, a temperature decrease significantly larger than for h-BN film without graphene enhancement. Finite element simulations of the h-BN film predict that further improvements in heat spreading ability are possible if the thermal contact resistance between the film and test chip are minimised.
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| 5. |
- Chen, W. H., et al.
(författare)
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Nanophotonics-based low-temperature PECVD epitaxial crystalline silicon solar cells
- 2016
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Ingår i: Journal of Physics D: Applied Physics. - : IOP Publishing. - 1361-6463 .- 0022-3727. ; 49:12
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Tidskriftsartikel (refereegranskat)abstract
- The enhancement of light absorption via nanopatterning in crystalline silicon solar cells is becoming extremely important with the decrease of wafer thickness for the further reduction of solar cell fabrication cost. In order to study the influence of nanopatterning on crystalline silicon thin-film solar cells, we applied two lithography techniques (laser interference lithography and nanoimprint lithography) combined with two etching techniques (dry and wet) to epitaxial crystalline silicon thin films deposited via plasma-enhanced chemical vapor deposition at 175 degrees C. The influence of nanopatterning with different etching profiles on solar cell performance is studied. We found that the etching profiles (pitch, depth and diameter) have a stronger impact on the passivation quality (open circuit voltage and fill factor) than on the optical performance (short circuit current density) of the solar cells. We also show that nanopatterns obtained via wet-etching can improve solar cell performance; and in contrast, dry-etching leads to poor passivation related to the etching profile, surface damage, and/ or contamination introduced during the etching process.
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| 6. |
- Edwards, Michael, 1986, et al.
(författare)
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Finite element simulation of 2D-based materials as heat spreaders
- 2016
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Ingår i: IMAPS Nordic Annual Conference 2016 Proceedings. - 9781510827226
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Konferensbidrag (refereegranskat)abstract
- Since the discovery of graphene, the first discovered 2D material, by Novoselov and Geim in 2004, the field of 2D materials has taken off and about 20 further 2D materials have been found. One of the most promising of these materials for the passive cooling of chips is hBN. HBN has the very unusual combination of being electrically insulating and thermally conductive, which potentially makes it an ideal material for both laterally spreading heat and passivating hotspots on chips. This gives hBN an advantage over graphene, where the chip requires a SiO2 passivation layer to prevent short circuits. To help evaluate the performance of these heat spreading films, a finite element model has been devised to support the experimental work undertaken in various publications. This model has been validated with experimental data and suggests that both graphene-And hBN-based materials have significant potential in lateral heat spreading applications.
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| 7. |
- Fu, Yifeng, 1984, et al.
(författare)
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Carbon nanotube growth on different underlayers for thermal interface material application
- 2016
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Ingår i: IMAPS Nordic Annual Conference 2016 Proceedings. - 9781510827226
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Konferensbidrag (refereegranskat)abstract
- Thermal interface material (TIM) is a critical component in thermal management of high density packaging systems since both the reliability and lifetime of microsystems are dependent on how the heat is dissipated. Carbon nanotubes (CNTs) are promising candidate for development of TIMs due to their excellent thermal and mechanical properties. The thermal conductivity of CNTs can be up to 3000 W/mK in the longitudinal direction which acts as ideal heat transfer path. However, the huge interfacial thermal resistance between CNTs and contact surface hinders the exploitation of CNTs as TIMs. In this paper, we will focus on the growth of CNTs on various substrates and underlayers and analyze the interaction between catalyst and underlayer materials. Microscopic analysis is performed to characterize the quality of the CNT materials and monitor the diffusion of Fe particles into different barrier layers. Thermal conductivity of the CNT TIMs will be measured to examine the performance of the materials.
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| 8. |
- Fu, Yifeng, 1984, et al.
(författare)
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Post-Growth Processing of Carbon Nanotubes for Interconnect Applications - A Review
- 2016
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Ingår i: 2016 6th Electronic System-Integration Technology Conference (Estc). - 9781509014026 ; , s. Article no 7764713-
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Konferensbidrag (refereegranskat)abstract
- Interconnect is one of the most important functions of packaging technology. It delivers power and signals into and out of electronic systems. The performance and reliability of microsystems are dependent on the interconnect quality. This paper reviews the chip-level interconnects based on carbon nanotubes (CNTs), this includes their applications for both on-chip and off-chip interconnects. Various post-growth processing of CNTs, such as doping, densification, transfer, metallization, etc., for the improvement of their performance will be reviewed.
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| 9. |
- Han, H. X., et al.
(författare)
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Functionalization mediates heat transport in graphene nanoflakes
- 2016
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- The high thermal conductivity of graphene and few-layer graphene undergoes severe degradations through contact with the substrate. Here we show experimentally that the thermal management of a micro heater is substantially improved by introducing alternative heat-escaping channels into a graphene-based film bonded to functionalized graphene oxide through amino-silane molecules. Using a resistance temperature probe for in situ monitoring we demonstrate that the hotspot temperature was lowered by similar to 28 degrees C for a chip operating at 1,300 Wcm(-2). Thermal resistance probed by pulsed photothermal reflectance measurements demonstrated an improved thermal coupling due to functionalization on the graphene-graphene oxide interface. Three functionalization molecules manifest distinct interfacial thermal transport behaviour, corroborating our atomistic calculations in unveiling the role of molecular chain length and functional groups. Molecular dynamics simulations reveal that the functionalization constrains the cross-plane phonon scattering, which in turn enhances in-plane heat conduction of the bonded graphene film by recovering the long flexural phonon lifetime.
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| 10. |
- Hansson, Josef, 1991, et al.
(författare)
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A review of recent progress of thermal interface materials: from research to industrial applications
- 2016
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Ingår i: IMAPS Nordic Annual Conference 2016 Proceedings; Tonsberg; Norway; 5 - 7 June 2016. - 9781510827226
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Konferensbidrag (refereegranskat)abstract
- The increasing trend of further scaling down electronic components put an increasing demand for more efficient cooling. A significant part of the thermal resistance from source to ambient occurs at the interface between materials, and thermal interface materials are crucial for efficient heat transfer. Recent years have seen a significant amount of progress various types of thermal interface materials. In this review, the field of thermal interface materials (TIMs) development is summarized and analyzed, focusing on three topics which have received attention at a research level, and their road towards market applicability. The first topic is development in particle laden polymers, which uses thermally conductive filler particles in a polymer matrix. New development is focused on novel fillers such as h-BN or carbon based fillers, and hybrid filler combinations. The next topic is continuous metal phase TIMs, which includes solder and liquid metal TIMs. The thermal performance is already very good, and development is largely focused on improving the mechanical properties. Finally, the last topic is carbon nanotube array TIMs, which used chemical vapor deposition-grown carbon nanotube arrays as bridging material. The concept has promise for great performance in both handling, mechanical stability and thermal performance, but is still at a research stage. In addition to these topics, a quantitative study on the progress of thermal interface materials development is made, both in terms of research papers published and in terms of patents filed. The study shows a stable trend of continuous development on all levels and concludes that significant improvements can be expected to continue in the future.
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