| 41. |
- Sun, Shuangxi, 1986, et al.
(författare)
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Mechanical and thermal characterization of a novel nanocomposite thermal interface material for electronic packaging
- 2016
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Ingår i: Microelectronics and Reliability. - : Elsevier BV. - 0026-2714. ; 56, s. 129-135
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a novel nanocomposite thermal interface material (Nano-TIM) consisting of a silver coated polyimide network and the indium matrix. One of the potential applications of this Nano-TIM is for heat dissipation in integrated circuits and electronic packaging. The shear strength of the Nano-TIM was investigated with DAGE-4000PSY shear tester. The shear strength of Nano-TIM is 4.5 MPa, which is 15% higher than that of the pure indium thermal interface material. The microstructure of cross-section and fracture surface was studied using Scanning Electron Microscopy (SEM). SEM pictures show a uniform polymer fiber distribution and solid interface between silver coated fibers and indium matrix. The thermal fatigue resistance of the Nano-TIM was evaluated by monitoring the variation of thermal interface resistance during the thermal cycling test (-40 to 125 degrees C). The thermal interface resistance was measured with a commercial xenon flash instrument after 100, 200, 300, 400, 500, and 1000 temperature cydes. The results-of thermal cycling test show that Nano-TIM presented consistent reliability performance with pure indium. Furthermore, the tooling effect of Nano-TIM was demonstrated through measuring the power chip temperature in the die attached structure by using an Infrared Camera. In the test, the Nano-TIM shows a comparable cooling effect to pure indium TIM for die attach applications in electronics packaging.
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| 42. |
- Sun, Shuangxi, 1986, et al.
(författare)
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Vertically aligned CNT-Cu nano-composite material for stacked through-silicon-via interconnects
- 2016
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Ingår i: Nanotechnology. - : IOP Publishing. - 1361-6528 .- 0957-4484. ; 27:33, s. Art no335705-
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Tidskriftsartikel (refereegranskat)abstract
- For future miniaturization of electronic systems using 3D chip stacking, new fine-pitch materials for through-silicon-via (TSV) applications are likely required. In this paper, we propose a novel carbon nanotube (CNT)/copper nanocomposite material consisting of high aspect ratio, vertically aligned CNT bundles coated with copper. These bundles, consisting of hundreds of tiny CNTs, were uniformly coated by copper through electroplating, and aspect ratios as high as 300: 1 were obtained. The resistivity of this nanomaterial was found to be as low as similar to 10(-8) Omega m, which is of the same order of magnitude as the resistivity of copper, and its temperature coefficient was found to be only half of that of pure copper. The main advantage of the composite TSV nanomaterial is that its coefficient of thermal expansion (CTE) is similar to that of silicon, a key reliability factor. A finite element model was set up to demonstrate the reliability of this composite material and thermal cycle simulations predicted very promising results. In conclusion, this composite nanomaterial appears to be a very promising material for future 3D TSV applications offering both a low resistivity and a low CTE similar to that of silicon.
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| 43. |
- Tripon-Canseliet, Charlotte, et al.
(författare)
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Experimental microwave complex conductivity extraction of vertically aligned MWCNT bundles for microwave subwavelength antenna design
- 2019
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Ingår i: Micromachines. - : MDPI AG. - 2072-666X. ; 10:9
-
Tidskriftsartikel (refereegranskat)abstract
- This paper reports the extraction of electrical impedance at microwave frequencies of vertically aligned multi-wall carbon nanotubes (VA MWCNT) bundles/forests grown on a silicon substrate. Dedicated resonating devices were designed for antenna application, operating around 10 GHz and benefiting from natural inductive/capacitive behavior or complex conductivity in the microwave domain. As obtained from S-parameters measurements, the capacitive and inductive behaviors of VA MWCNT bundles were deduced from device frequency resonance shift.
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| 44. |
- Wang, Nan, 1988, et al.
(författare)
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Flexible Multifunctionalized Carbon Nanotubes-Based Hybrid Nanowires
- 2015
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Ingår i: Advanced Functional Materials. - : Wiley. - 1616-3028 .- 1616-301X. ; 25:26, s. 4135-4143
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, flexible multifunctionalized carbon nanotube (CNT)-based hybrid nanowires are synthesized through surface modification processes. The good dispersability of the hybrid nanowire in polar solvents facilitates directly making fine patterns with a minimum width of 40 μm for applications of flexible and stretchable circuits (FSCs). The hybrid nanowire possesses a flexible and highly conductive structure which demonstrates stable electro-mechanical properties on polydimethylsiloxane (PDMS) substrates under large structural deformation. FSCs fabricated from the hybrid nanowires show a constant resistance of 0.096 Ω □-1 (equivalent of a resistivity 0.96 Ω μm) under repeated bending cycles. The FSCs also have a low and stable sheet resistance of 0.4 Ω □-1 for strains up to 30%, which is almost four orders of magnitude lower than that of pure CNT samples (1316 Ω □-1). Further improved stretchability and electro-mechanical properties (0.1 Ω □-1, at the strain of 100%) are achieved with a prestrain PDMS substrate. Repeated deformation tests demonstrate the high reliability of FSCs. The observed stable and reliable electro-mechanical performance of FSCs suggests the potential use of the material in wearable and portable electronics. Multifunctionalized hybrid nanowires based on carbon nanotubes are prepared through different surface modification processes. These hybrid nanowires exhibit both the high electrical conductivity of metal and excellent mechanical properties of carbon nanotubes together with good dispersability. Flexible and stretchable electrodes based on the hybrid nanowires demonstrate stable electro-mechanical properties under large structural deformations.
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| 45. |
- Zehri, Abdelhafid, 1989, et al.
(författare)
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Graphene Fibres: Towards high mechanical, thermal and electrical properties state of art
- 2016
-
Ingår i: IMAPS Nordic Annual Conference 2016, Tonsberg, Norway, 5-7 June 2016. - 9781510827226
-
Konferensbidrag (refereegranskat)abstract
- Nowadays, tremendous efforts are made to enhance the thermal conductivity of materials and answer to demands for fast heat dissipation in various applications such as wearable electronics, photovoltaic energy conversion and advanced structural materials mounted on high power electronics. The main difficulty comes very often from the ability to simultaneously produce superior thermal, electrical and high mechanical properties. For this matter, graphene which owned the nickname of miracle material has attracted all the attention to exploit its outstanding properties at an industriel scale and the field of graphene fibre turned to be a very promising approach to produce a high quality 3D graphene material. In this review paper, we propose to summarize briefly the different advances and attemps made up to now in order the assemble graphene into macroscopic three-dimensional structures and apply the unique properties of its two-dimensional individuels in practical applications.
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| 46. |
- Zhang, Yong, 1982, et al.
(författare)
-
2D HEAT DISSIPATION MATERIALS FOR MICROELECTRONICS COOLING APPLICATIONS
- 2016
-
Ingår i: China Semiconductor Technology International Conference 2016, CSTIC 2016. - 9781467388047
-
Konferensbidrag (refereegranskat)abstract
- The need for faster and smaller, as well as more reliable and efficient consumer electronic products has resulted in microelectronic components that produce progressively more heat. The resultant reliability issues from the increased heat flux are serious and hinder technological development. One solution for microelectronics cooling applications is 2D materials applied as heat spreaders and these include monolayer graphene, graphene based films, and monolayer hexagonal boron nitride and BN based films. In addition, thermal performances of the graphene heat spreader were also studied under different packaging structures, including wire bonding, cooling fins and flip chips. Finally, 2D hexagonal Boron nitride (h-BN) heat spreaders, fabricated by different methods, had their heat dissipation performances characterized by different thermal characterization methods, such as resistance temperature detector (RTD) and Infrared (IR) methods. In conclusion, these new novel 2D materials developed show great potential for microelectronics cooling applications.
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| 47. |
- Zhang, Yong, 1982, et al.
(författare)
-
Characterization and simulation of liquid phase exfoliated graphene-based films for heat spreading applications
- 2016
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Ingår i: Carbon. - : Elsevier BV. - 0008-6223. ; 106, s. 195-201
-
Tidskriftsartikel (refereegranskat)abstract
- This paper concerns the thermal properties of graphene-based films for heat spreading applications. Following liquid phase exfoliation (LPE) films were made by two different methods, vacuum filtration and drop coating. Temperature decreases of up to 6 °C and 4 °C were measured at a heat flux density of 1200 W/cm2 for the vacuum filtrated and drop coated films respectively. For the first time in this paper, three different methods were combined to evaluate and predict the thermal performance of such graphene-based films. Resistance thermometers were used to monitor the hotspot temperature decrease versus the Joule heat flow as a result of using graphene-based heat spreaders. The 3ω method was used to experimentally determine the in-plane and through-plane thermal conductivities of such films. A finite element model of the hotspot test structure was setup using the in-plane and through-plane thermal conductivities (110 and 0.25 W/mK, respectively) obtained from the 3ω measurements. Simulations were performed to predict the hotspot temperature decrease with excellent agreement obtained between all methods. The results indicate that the alignment and purity of the graphene-based films, as well as their thermal boundary resistance with respect to the chip, are key parameters when determining the thermal performance of graphene-based heat spreaders.
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| 48. |
- Zhang, Yong, 1982, et al.
(författare)
-
Chemical vapor deposition grown graphene on Cu-Pt alloys
- 2017
-
Ingår i: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 193, s. 255-258
-
Tidskriftsartikel (refereegranskat)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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| 49. |
- Zhang, Yong, 1982, et al.
(författare)
-
Graphene-based heater
- 2016
-
Ingår i: IMAPS Nordic Annual Conference 2016; Tonsberg; Norway; 5-7 June 2016. - 9781510827226
-
Konferensbidrag (refereegranskat)abstract
- The excellent thermal conductivity and optical transmittance of graphene make it tremendously interesting as a material for heating applications. In this paper, we demonstrate graphene can be used as a new heating element. The graphene is synthesized by chemical vapor deposition (CVD) on Cu foil. The heating performance is studied in terms of applied voltage, heating rate and input power density. A two-layer graphene film based heater can reach an equilibrium temperature up to 90C when 60 V voltage is applied for 2 min. A maximum heating rate of 1.1 C/s was observed under an applied voltage of 60 V. The results indicate that the graphene-based heater holds great promise for many applications such as defrosting and antifogging devices.
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| 50. |
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