Degradation of Carbon Nanotube Array Thermal Interface Materials through Thermal Aging: Effects of Bonding, Array Height, and Catalyst Oxidation

Abstract

Carbon nanotube (CNT) array thermal interface materials (TIMs) are promising candidates for high-performance applications in terms of thermal performance. However, in order to be useful in commercial applications, the reliability of the interfaces is an equally important parameter, which so far has not been thoroughly investigated. In this study, the reliability of CNT array TIMs is investigated through accelerated aging. The roles of CNT array height and substrate configuration are studied for their relative impact on thermal resistance degradation. After aging, the CNT catalyst is analyzed using X-ray photoelectron spectroscopy to evaluate chemical changes. The CNT-catalyst bond appears to degrade during aging but not to the extent that the TIM performance is compromised. On the other hand, coefficient of thermal expansion mismatch between surfaces creates strain that needs to be absorbed, which requires CNT arrays with sufficient height. Transfer and bonding of both CNT roots and tips also create more reliable interfaces. Crucially, we find that the CNT array height of most previously reported CNT array TIMs is not enough to prevent significant reliability problems.

Magnetically oriented 3D-boron nitride nanobars enable highly efficient heat dissipation for 3D integrated power packaging

“…Superparamagnetic iron oxide is electrostatically adsorbed onto h-BN nanosheets on the outer surface of BNNB under the catalysis of a cationic surfactant. 21,37 Figs. 1 (d-f) show Fe 3 O 4 nanoparticles uniformly distributed on the surface of BNNB, and (g) shows Fe 3 O 4 @BNNB dispersed in deionized water being attracted by a permanent magnet.…”

Magnetically Oriented 3D-Boron Nitride Nanobars Enable Efficient Heat Dissipation for 3D-Integrated Power Packaging

“…To enhance its orderliness, we resorted to its barb characteristic. Superparamagnetic iron oxide is electrostatically adsorbed onto h-BN nanosheets on the outer surface of BNNB under the catalysis of a cationic surfactant. , Figure e,f shows TEM images of BNNB with different resolutions, Figure g,h shows TEM images of Fe 3 O 4 @BNNB at different resolutions, where Figure h shows the Fe 3 O 4 particles can be attached to the surface of BNNB, Figure i,j shows BNNB powder and Fe 3 O 4 @BNNB powder, and Figure k shows Fe 3 O 4 @BNNB dispersed in deionized water being attracted by a permanent magnet. The magnetically functionalized Fe 3 O 4 @BNNB powder is then mixed into a low-viscosity aqueous epoxy resin slurry, which is dispersed uniformly by using tip ultrasonication.…”

Carbon dioxide-boosted growth of high-density and vertically aligned carbon nanotube arrays on a stainless steel mesh

“…, ∼10 9 –10 13 cm −2 , quantified by the number density of CNTs on a substrate) than that of horizontally aligned CNT arrays (HACNTs, ∼10 4 cm −2 ), thus showing great potential in a wide range of applications. 10–15…”

“…In particular, the vertically aligned CNT arrays (VACNTs) 9 have achieved yields of several orders of magnitude higher (e.g., ∼10 9 -10 13 cm −2 , quantied by the number density of CNTs on a substrate) than that of horizontally aligned CNT arrays (HACNTs, ∼10 4 cm −2 ), thus showing great potential in a wide range of applications. [10][11][12][13][14][15] Catalytic chemical vapor deposition (CCVD) has been one of the most commonly utilized approaches for preparing CNT arrays because of its simple operation, low cost, and relatively high growth efficiency. 16 Up to date, VACNTs with millimeter-scale heights has been typically achieved by depositing catalysts on SiO 2 /Si substrates with an Al 2 O 3 buffer layer.…”