Metallic Nanocomposites as Next-Generation Thermal Interface Materials

Xuhui Feng, Sreekant Narumanchi, Nirup Nagabandi, Jun Oh, Mustafa Akbulut, Cengiz Yegin, Charles King

Research output: Contribution to conferencePaperpeer-review

4 Scopus Citations

Abstract

Thermal interface materials (TIMs) are an integral and important part of thermal management in electronic devices. The electronic devices are becoming more compact and powerful. This increase in power processed or passing through the devices leads to higher heat fluxes and makes it a challenge to maintain temperatures at the optimal level during operation. Herein, we report a free standing nanocomposite TIM in which boron nitride nanosheets (BNNS) are uniformly dispersed in copper matrices via an organic linker, thiosemicarbazide. Integration of these metal-organic-inorganic nanocomposites was made possible by a novel electrodeposition technique where the functionalized BNNS (f-BNNS) experience the Brownian motion and reach the cathode through diffusion, while the nucleation and growth of the copper on the cathode occurs via the electrochemical reduction. Once the f-BNNS bearing carbonothioyl/thiol groups on the terminal edges come into the contact with copper crystals, the chemisorption reaction takes place. We performed thermal, mechanical, and structural characterization of these nanocomposites using scanning electron microcopy (SEM), diffusive laser flash (DLF) analysis, phase-sensitive transient thermoreflectence (PSTTR), and nanoindentation. The nanocomposites exhibited a thermal conductivity ranging from 211 W/mK to 277 W/mK at a filler mass loading of 0-12 wt.%. The nanocomposites also have about 4 times lower hardness as compared to copper, with values ranging from 0.27 GPa to 0.41 GPa. The structural characterization studies showed that most of the BNNS are localized at grain boundaries - which enable efficient thermal transport while making the material soft. PSTTR measurements revealed that the synergistic combinations of these properties yielded contact resistances on the order of 0.10 to 0.13 mm2K/W, and the total thermal resistance of 0.38 to 0.56 mm2K/W at bondline thicknesses of 30-50 pm. The coefficient of thermal expansion (CTE) of the nanocomposite is 11 ppm/K, which lies between the CTEs of aluminum (22 ppm/K) and silicon (3 ppm/K), which are common heat sink and heat source materials, respectively. The nanocomposite can also be deposited directly on to heat sink which will simplify the packaging processes by removing one possible element to assemble. These unique properties and ease of assembly makes the nanocomposite a promising next-generation TIM.

Original languageAmerican English
Pages400-406
Number of pages7
DOIs
StatePublished - 25 Jul 2017
Event16th IEEE InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 2017 - Orlando, United States
Duration: 30 May 20172 Jun 2017

Conference

Conference16th IEEE InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 2017
Country/TerritoryUnited States
CityOrlando
Period30/05/172/06/17

Bibliographical note

See NREL/CP-5400-68120 for preprint

NREL Publication Number

  • NREL/CP-5400-70643

Keywords

  • (Power) Electronics
  • Electrodeposition
  • Nanocomposite
  • Thermal Management
  • TIM

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