Control of Nanoplane Orientation in voBN for High Thermal Anisotropy in a Dielectric Thin Film: A New Solution for Thermal Hotspot Mitigation in Electronics
Journal article, 2017
High anisotropic thermal materials, which allow heat to dissipate in a preferential direction, are of interest as a prospective material for electronics as an effective thermal management solution for hot spots. However, due to their preferential heat propagation in the in-plane direction, the heat spreads laterally instead of vertically. This limitation makes these materials ineffective as the density of hot spots increases. Here, we produce a new dielectric thin film material at room temperature, named vertically ordered nanocrystalline h-BN (voBN). It is produced such that its preferential thermally conductive direction is aligned in the vertical axis, which facilitates direct thermal extraction, thereby addressing the increasing challenge of thermal crosstalk. The uniqueness of voBN comes from its h-BN nanocrystals where all their basal planes are aligned in the direction normal to the substrate plane. Using the 3 omega method, we show that voBN exhibits high anisotropic thermal conductivity (TC) with a 16-fold difference between through-film TC and in-plane TC (respectively 4.26 and 0.26 W.m(-1).K-1). Molecular dynamics simulations also concurred with the experimental data, showing that the origin of this anisotropic behavior is due to the nature of voBN's plane ordering. While the consistent vertical ordering provides an uninterrupted and preferred propagation path for phonons in the through-film direction, discontinuity in the lateral direction leads to a reduced in-plane TC. In addition, we also use COMSOL to simulate how the dielectric and thermal properties of voBN enable an increase in hot spot density up to 295% compared with SiO2, without any temperature increase.
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Author
O. Cometto
Nanyang Technological University
Kabir Majid Samani
Electronics Material and Systems
B. Liu
Nanyang Environment and Water Research Institute
S. Sun
Chalmers University of Technology
S. H. Tsang
Nanyang Technological University
Johan Liu
Chalmers, Microtechnology and Nanoscience (MC2), Photonics
Electronics Material and Systems
K. Zhou
Nanyang Technological University
E. H. T. Teo
Nanyang Technological University
ACS Applied Materials & Interfaces
1944-8244 (ISSN) 1944-8252 (eISSN)
Vol. 9 8 7456-7464Areas of Advance
Nanoscience and Nanotechnology
Subject Categories (SSIF 2011)
Computer and Information Science
DOI
10.1021/acsami.6b15014