| 1. |
- Bao, Jie, et al.
(författare)
-
Synthesis and Applications of Two-Dimensional Hexagonal Boron Nitride in Electronics Manufacturing
- 2016
-
Ingår i: Electronic Materials Letters. - : Springer Science and Business Media LLC. - 1738-8090 .- 2093-6788. ; 12:1, s. 1-16
-
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.
|
|
| 2. |
- Bao, Jie, 1982, et al.
(författare)
-
Two-dimensional hexagonal boron nitride as lateral heat spreader in electrically insulating packaging
- 2016
-
Ingår i: Journal of Physics D: Applied Physics. - : IOP Publishing. - 1361-6463 .- 0022-3727. ; 49:July 2016, s. 265501-
-
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.
|
|
| 3. |
- Fu, Yifeng, 1984, et al.
(författare)
-
Thermal Characterization of Low-Dimensional Materials by Resistance Thermometers
- 2019
-
Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 12:11
-
Forskningsöversikt (refereegranskat)abstract
- The design, fabrication, and use of a hotspot-producing and temperature-sensing resistance thermometer for evaluating the thermal properties of low-dimensional materials are described in this paper. The materials that are characterized include one-dimensional (1D) carbon nanotubes, and two-dimensional (2D) graphene and boron nitride films. The excellent thermal performance of these materials shows great potential for cooling electronic devices and systems such as in three-dimensional (3D) integrated chip-stacks, power amplifiers, and light-emitting diodes. The thermometers are designed to be serpentine-shaped platinum resistors serving both as hotspots and temperature sensors. By using these thermometers, the thermal performance of the abovementioned emerging low-dimensional materials was evaluated with high accuracy.
|
|
| 4. |
- Huang, Shirong, et al.
(författare)
-
Infrared Emissivity Measurement for Vertically Aligned Multiwall Carbon Nanotubes (CNTs) Based Heat Spreader Applied in High Power Electronics Packaging
- 2016
-
Ingår i: 6th Electronic System-integration Technology Conference (ESTC 2016). - 9781509014026 ; , s. Article no 7764696-
-
Konferensbidrag (refereegranskat)abstract
- Vertically-aligned multiwall carbon nanotubes were deposited on silicon substrate by low pressure chemical vapor deposition (LPCVD), which can be utilized as heat spreaders in high power electronic packaging due to their remarkable thermal conductivity. The infrared emissivity of the vertically aligned multiwall carbon nanotubes was then characterized based on the FLIR SC600 infrared imaging system. The average infrared emissivity of the multiwall carbon nanotubes sample was about 0.92, which agrees well with experimental results reported before. Scanning electron microscopy (SEM) images of the multiwall carbon nanotubes were further analyzed to explain its high emissivity, and the reason can be attributed to the homogeneous sparseness and aligned structure of the vertically aligned multiwall carbon nanotubes
|
|
| 5. |
- Huang, Shirong, et al.
(författare)
-
The Effects of Graphene-Based Films as Heat Spreaders for Thermal Management in Electronic Packaging
- 2016
-
Ingår i: 2016 17th International Conference on Electronic Packaging Technology, ICEPT 2016. - 9781509013968 ; , s. Art no 7583272; Pages 889-892
-
Konferensbidrag (refereegranskat)abstract
- Graphene-based films (GBF) were fabricated using a chemical conversion process including graphene oxide (GO) preparation by use of Hummer’s method, graphene oxide reduction using L-ascorbic acid (LAA), and finally film formation by vacuum filtration. GBF is considered as a candidate material for thermal management, i.e. for removing heat from hotspots in power electronic packaging, due to its high thermal conductivity. In this work, the GBF heat spreading performance in 3D TSV packaging was analysed using finite element methods (FEM) implemented in the COMSOL software. Both size effects and the influence of the thermal conductivity of the GBF heat spreader on the thermal performance of the 3D TSV package were evaluated. Furthermore, the size effects of the thermal conductive adhesive (TCA) underfill between the chip and the printed circuit board (PCB) were analysed. The results obtained are critical for proper design of graphene-based lateral heat spreaders in high power electronic packaging.
|
|
| 6. |
- Jeppson, Kjell, 1947, et al.
(författare)
-
Hotspot test structures for evaluating carbon nanotube microfin coolers and graphene-like heat spreaders
- 2016
-
Ingår i: 29th IEEE International Conference on Microelectronic Test Structures (ICMTS), Yokohama, Japan, Mar 28-31, 2016. - 1071-9032. ; 2016-May, s. 32-36
-
Konferensbidrag (refereegranskat)abstract
- The design, fabrication, and use of a hotspot-producing and temperature-sensing test structure for evaluating the thermal properties of carbon nanotubes, graphene and boron nitride for cooling of electronic devices in applications like 3D integrated chip-stacks, power amplifiers and light-emitting diodes is described. The test structure is a simple meander-shaped metal resistor serving both as the hotspot and the temperature thermo-meter. By use of this test structure, the influence of emerging materials like those mentioned above on the temperature of the hotspot has been evaluated with good accuracy).
|
|
| 7. |
- Jiang, Di, 1983, et al.
(författare)
-
A flexible and stackable 3D interconnect system using growth-engineered carbon nanotube scaffolds
- 2017
-
Ingår i: Flexible and Printed Electronics. - : IOP Publishing. - 2058-8585. ; 2:2
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 8. |
- Jiang, Di, 1983, et al.
(författare)
-
Embedded Fin-Like Metal/CNT Hybrid Structures for Flexible and Transparent Conductors
- 2016
-
Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 12:11, s. 1521-1526
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, an embedded fin-like metal-coated carbon nanotube (Fin-M/CNT) structure is demonstrated for flexible and transparent conductor wire applications. Embedded in a polydimethylsiloxane polymeric substrate, Fin-M/CNT wires with a minimum width of 5 μm and a minimum pitch of 10 μm have been achieved. Direct current resistances of single Fin-M/CNT wires, where the supporting CNT structures have been covered by Ti/Al/Au metal coatings of different thicknesses, have been measured. The high aspect ratio of the fin-like structures not only improves the adhesion between the wires and the polymeric substrate, but also yields a low resistance at a small surface footprint. In addition, transparent Fin-M/CNT grid lines with hexagonal patterns, with a sheet resistance of as low as 45 Ω sq−1, have been achieved at an optical transmittance of 88%. The robustness of the Fin-M/CNT structures has been demonstrated in bending tests up to 500 cycles and no significant changes in wire resistances are observed.
|
|
| 9. |
- Jiang, Di, 1983, et al.
(författare)
-
Vertically stacked carbon nanotube-based interconnects for through silicon via application
- 2015
-
Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 36:5, s. 499-501
-
Tidskriftsartikel (refereegranskat)abstract
- Stacking of silicon chips with carbon nanotube (CNT)-based through-silicon vias (TSVs) is experimentally demonstrated. Polymer filling is used to improve the transfer quality of CNTs into pre-etched silicon holes. Special hexagonal CNTs are designed to achieve high aspect ratio (10:1) CNT vias. TSVs filled with closely packed CNTs show a highly linear dc I - V response. The proposed process works at room temperature, which makes it compatible with existing device fabrication flow.
|
|
| 10. |
- Kabiri Samani, Majid, 1976, et al.
(författare)
-
Improving Thermal Transport at Carbon Hybrid Interfaces by Covalent Bonds
- 2018
-
Ingår i: Advanced Materials Interfaces. - : Wiley. - 2196-7350. ; 5:15
-
Tidskriftsartikel (refereegranskat)abstract
- Graphene and carbon nanotubes have received much attention for thermal management application due to their unique thermal performance. Theoretical work suggests that a covalent bond can combine 1D carbon nanotubes with 2D graphene together to extend the excellent thermal property to three dimensions for heat dissipation. This paper experimentally demonstrates the high heat dissipation capability of a freestanding 3D multiwall carbon nanotube (MWCNT) and graphene hybrid material. Using high-resolution transmission electron microscopy and pulsed photothermal reflection measurement method, the covalent bonds between MWCNT and planar graphene are microscopically and numerically demonstrated. Thermal resistance at the junction with covalent bonds is 9×10^−10 Kelvin square meter per watt, which is three orders of magnitude lower than van der Waals contact. Joule heating method is used to verify the extra cooling effect of this 3D hybrid material compared to graphite film. A demonstrator using high power chip is developed to demonstrate the applicability of this hybrid material in thermal application. Temperature at hot spots can be decreased by around 10°C with the assistance of this hybrid material. These findings are very significant for understanding the thermal conduction during combining 1D and 2D carbon material together for future thermal management application.
|
|
