Thermal and Electrical Transport in Carbon Nanofiber Interconnects

We study reliability of carbon nanofibers (CNFs) under high-current stress by examining CNF breakdown on four different configurations, suspended or supported, with/without tungsten deposition. The suspended results are consistently explained with a heat transport model taking into account Joule heating and heat dissipation along the CNF, while supported cases show a consistently larger current density just before breakdown, reflecting effective heat dissipation to the substrate.

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Heat transport simulations in a heterogeneous aquifer used for aquifer thermal energy storage (ATES)

Canadian Geotechnical Journal ◽

10.1139/t09-078 ◽

2010 ◽

Vol 47 (1) ◽

pp. 96-115 ◽

Cited By ~ 25

Author(s):

D. W. Bridger ◽

D. M. Allen

Keyword(s):

Energy Storage ◽

Heat Transport ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Heat Dissipation ◽

Transport Model ◽

Three Dimensional ◽

Heterogeneous Aquifer ◽

Aquifer Thermal Energy Storage ◽

Production Wells

A modelling study was carried out to evaluate the influence of aquifer heterogeneity, as represented by geologic layering, on heat transport and storage in an aquifer used for aquifer thermal energy storage (ATES). An existing ATES system in Agassiz, British Columbia, Canada, was used as a case study. The system consists of four production wells completed in an unconfined heterogeneous aquifer consisting of interbedded sands and gravels. An additional dump well was installed to provide for heat dissipation during the peak cooling periods. Three monitoring wells and the production wells were logged for temperature periodically within the first 1.5 years of operation. A three-dimensional groundwater flow and heat transport model was developed using FEFLOW. Simulation results indicate that heat and (or) cold energy moved preferentially in discrete zones within the aquifer or at least entered the wells over discrete intervals. Monitoring data support model results, but show that thermal storage was successfully achieved despite a significant cooling operation during the first year.

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High-Current Reliability of Carbon Nanofibers for Interconnect Applications

MRS Proceedings ◽

10.1557/proc-1018-ee10-07 ◽

2007 ◽

Vol 1018 ◽

Author(s):

Hirohiko Kitsuki ◽

Makoto Suzuki ◽

Quoc Ngo ◽

Kristofer Gleasson ◽

Alan M. Cassell ◽

...

Keyword(s):

Carbon Nanofibers ◽

Scanning Transmission Electron Microscopy ◽

Structural Damage ◽

Heat Dissipation ◽

High Reliability ◽

High Current ◽

Transmission Electron ◽

Scanning Transmission ◽

Long Time

AbstractWe present a high-current reliability study of carbon nanofibers (CNFs) for interconnect applications. In situ scanning transmission electron microscopy (STEM) reveals structural damage to CNFs after current stress. The effect of heat dissipation on the current capacity is also discussed by using different experimental configurations. Long-time reliability tests are performed with a vertical via interconnect structure, showing promising high reliability of CNF interconnects for future electronic devices.

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Long-Term Electrically Stable Silver Nanowire Composite Transparent Electrode Under High Current Density

10.21203/rs.3.rs-287036/v1 ◽

2021 ◽

Author(s):

Kaiqing Wang ◽

Yunxia Jin ◽

Fei Xiao

Keyword(s):

Current Density ◽

Composite Electrode ◽

High Current Density ◽

Transparent Electrode ◽

Silver Nanowire ◽

Electrical Performance ◽

High Current ◽

Electrical Stability ◽

Current Stress

Abstract Silver nanowire (AgNW) network has been employed to many electronic devices as transparent electrode. However, the poor electrical stability under current has been seriously holding its practical application, and we still lack long-term electrically stable AgNW system to study the underlying fundamental of electrical failure. In this work, the electrical performance and failure mechanism of chitosan-ascorbic acid (Chi-AsA)/AgNW composite under current stress were thoroughly studied. The composite electrode maintained stability above 24000 h under high current density of 100 mA cm-1. The main failure in AgNW composite is found to be a wave break perpendicular to the current rather than traditional uniform degradation across AgNW networks. More interestingly, the AgNWs in failed composite electrode kept their original smooth morphology excepting the crack area, while the AgNWs in pristine networks degraded to nanoparticles or became disconnected everywhere. The patterned AgNW composite in microscale exhibits similar long lifetime in resisting current stress as the bulk composite film. The effect of over-coating position, electrical stress, temperature and over-coating materials on the electrical stability were studied. The over-coating layer of Chi-AsA is proven to suppress the silver atoms from migration, reduce the concentrated Joule heating at junctions, and inhibit the corrosion. The Chi-AsA/AgNW composite enables electrically stable transparent conductor for next-generation optoelectronics, and the mechanism investigation may provide effective means of preparing electrically stable AgNW systems.

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Experimental Study of Damage Mechanism of Carbon Nanotube as Nanocomponent of Electronic Devices Under High Current Density

Journal of Electronic Packaging ◽

10.1115/1.4026878 ◽

2014 ◽

Vol 136 (4) ◽

Author(s):

Kazuhiko Sasagawa ◽

Kazuhiro Fujisaki ◽

Jun Unuma ◽

Ryota Azuma

Keyword(s):

Carbon Nanotubes ◽

Joule Heating ◽

Current Density ◽

High Current Density ◽

Damage Mechanism ◽

Cathode Side ◽

Testing System ◽

High Current ◽

Multiwalled Carbon ◽

And Migration

The damage mechanisms of carbon nanotubes are considered to be the oxidation by Joule heating and migration of carbon atoms by high-density electron flows. In this study, a high current density testing system was designed and applied to multiwalled carbon nanotubes (MWCNTs) collected at the gap between thin-film electrodes. Local evaporation of carbon atoms occurred on the cathode side of the MWCNTs under relatively low current density conditions, and the center area of the MWCNTs under high current density conditions. The damaged morphology could be explained by considering both Joule heating and electromigration behavior of MWCNTs.

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Thermoreflectance Measurement of Temperature and Thermal Resistance of Thin Film Gold

Journal of Heat Transfer ◽

10.1115/1.4007068 ◽

2012 ◽

Vol 134 (11) ◽

Cited By ~ 9

Author(s):

Christopher Cardenas ◽

Drazen Fabris ◽

Shawn Tokairin ◽

Francisco Madriz ◽

Cary Y. Yang

Keyword(s):

Thin Film ◽

Integrated Circuits ◽

Thermal Resistance ◽

Heat Transport ◽

Joule Heating ◽

Transport Model ◽

Unit Area ◽

Thermal Contact ◽

Thermal Dissipation ◽

Reduced Dimensions

To improve performance and reliability of integrated circuits, accurate knowledge of thermal transport properties must be possessed. In particular, reduced dimensions increase boundary scattering and the significance of thermal contact resistance. A thermoreflectance measurement can be used with a valid heat transport model to experimentally quantify the contact thermal resistance of thin film interconnects. In the current work, a quasi-steady state thermoreflectance measurement is used to determine the temperature distribution of a thin film gold interconnect (100 nm) undergoing Joule heating. By comparing the data to a heat transport model accounting for thermal diffusion, dissipation, and Joule heating, a measure of the thermal dissipation or overall thermal resistance of unit area is obtained. The gold film to substrate overall thermal resistance of unit area beneath the wide lead (10 μm) and narrow line (1 μm) of the interconnect are 1.64 × 10−6 m2 K/W and 5.94 × 10−6 m2 K/W, respectively. The thermal resistance of unit area measurements is comparable with published results based on a pump-probe thermoreflectance measurement.

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Modeling of Temperature Increase Due to Joule Heating During Electromigration Measurements

MRS Proceedings ◽

10.1557/proc-427-113 ◽

1996 ◽

Vol 427 ◽

Cited By ~ 1

Author(s):

H. C. Louie Liu ◽

S. P. Murarka

Keyword(s):

Joule Heating ◽

Current Density ◽

High Current Density ◽

Test Surface ◽

High Current ◽

Electrical Field ◽

Iteration Functions ◽

Electrical Analogy ◽

Heat Conduction And Convection ◽

Applied Electrical Field

AbstractElectromigration (EM), the mass transport phenomenon under applied electrical field, is known to cause degradation in interconnections and thus to compromise the devices' reliability. High current density and high temperature conditions are usually adopted to evaluate the EM lifetime. Such high current density will raise the temperature at the test sites because of Joule heating. Thus the actual temperature on the test surface, not the ambient temperature, is an important parameter affecting the lifetime of the metallization. A simple model is proposed here to predict the temperature rise in such interconnections and the calculated values agree well with the experimentally measured rise in temperature. Only heat conduction and convection are considered and illustrative equivalent electrical analogy technique is used to solve the problem. This model, using a commercially available spreadsheet and its iteration functions, is shown to match closely with experimental results.

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Cytocompatibility of Carbon Nanofiber Materials for Neural Applications

MRS Proceedings ◽

10.1557/proc-774-o7.35 ◽

2003 ◽

Vol 774 ◽

Author(s):

Janice L. McKenzie ◽

Michael C. Waid ◽

Riyi Shi ◽

Thomas J. Webster

Keyword(s):

Carbon Fiber ◽

Surface Energy ◽

Carbon Nanofibers ◽

Carbon Fibers ◽

Carbon Nanofiber ◽

Fiber Composite ◽

Scar Tissue ◽

Pc 12 Cells ◽

Low Surface Energy ◽

Poly Carbonate

AbstractSince the cytocompatibility of carbon nanofibers with respect to neural applications remains largely uninvestigated, the objective of the present in vitro study was to determine cytocompatibility properties of formulations containing carbon nanofibers. Carbon fiber substrates were prepared from four different types of carbon fibers, two with nanoscale diameters (nanophase, or less than or equal to 100 nm) and two with conventional diameters (or greater than 200 nm). Within these two categories, both a high and a low surface energy fiber were investigated and tested. Astrocytes (glial scar tissue-forming cells) and pheochromocytoma cells (PC-12; neuronal-like cells) were seeded separately onto the substrates. Results provided the first evidence that astrocytes preferentially adhered on the carbon fiber that had the largest diameter and the lowest surface energy. PC-12 cells exhibited the most neurites on the carbon fiber with nanodimensions and low surface energy. These results may indicate that PC-12 cells prefer nanoscale carbon fibers while astrocytes prefer conventional scale fibers. A composite was formed from poly-carbonate urethane and the 60 nm carbon fiber. Composite substrates were thus formed using different weight percentages of this fiber in the polymer matrix. Increased astrocyte adherence and PC-12 neurite density corresponded to decreasing amounts of the carbon nanofibers in the poly-carbonate urethane matrices. Controlling carbon fiber diameter may be an approach for increasing implant contact with neurons and decreasing scar tissue formation.

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Cytocompatibility and Material Properties of Poly-carbonate Urethane/Carbon Nanofiber Composites for Neural Applications

MRS Proceedings ◽

10.1557/proc-774-o7.30 ◽

2003 ◽

Vol 774 ◽

Author(s):

Janice L. McKenzie ◽

Michael C. Waid ◽

Riyi Shi ◽

Thomas J. Webster

Keyword(s):

Mechanical Properties ◽

Carbon Nanofibers ◽

Material Properties ◽

Carbon Nanofiber ◽

Scar Tissue ◽

Tissue Response ◽

Positive Interactions ◽

Weight Percentage ◽

Poly Carbonate

AbstractCarbon nanofibers possess excellent conductivity properties, which may be beneficial in the design of more effective neural prostheses, however, limited evidence on their cytocompatibility properties exists. The objective of the present in vitro study was to determine cytocompatibility and material properties of formulations containing carbon nanofibers to predict the gliotic scar tissue response. Poly-carbonate urethane was combined with carbon nanofibers in varying weight percentages to provide a supportive matrix with beneficial bulk electrical and mechanical properties. The substrates were tested for mechanical properties and conductivity. Astrocytes (glial scar tissue-forming cells) were seeded onto the substrates for adhesion. Results provided the first evidence that astrocytes preferentially adhered to the composite material that contained the lowest weight percentage of carbon nanofibers. Positive interactions with neurons, and, at the same time, limited astrocyte functions leading to decreased gliotic scar tissue formation are essential for increased neuronal implant efficacy.

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